351 cleveland flat plane crank

This engine was rated at 118 horsepower and 193 lb-ft of torque. This engine was born to make torque for full-size cars and trucks; hence the heavy-duty 5M crank and D1AE 6.580- inch (center to center) connecting rods. Its a no-twist formula that comes from a special heat-treating and shot-peening process that ensures pinpoint accuracy at high RPM. Callies Crankshafts are at the top of the industry for quality of finish and reliability. These cranks can be used in a 351W block by using the appropriate bearing spacers. The offenhauser power port short runner tunnel ram with twin 600 Holley vac sec carbs, 12.4 trw pistons, and 108 lobe center sig Erson hi flow I M cam running AV gas was absolutely a rocket ship on the street. Ford Toploader Four Speed manual transmission, top loader recently removed from XY 351 that is going to C4, box is in good working order, very clean and turns over real nice, RUG BF Wide Ratio, 28 spline output shaft, one ear has previously been repaired, inspection welcome, ready to fit, suit 302 351 Cleveland and Windsor engines, located 4118 Logan QLD, local pickup preferred, may suit xr Xt . The answer was simple, the Cleveland familyand the 4V version more specificallyoffered massive head flow. Short of a flat plane crank or 180 degree headers, no, you will not get the even exhaust pulsing you are after. to 452 horsepower and 412 ft.-lbs. Stroke, External Balance, Ford, 351C, Each, Estimated USA Ship Date: The 351C, 400, and 351M all have a two-piece rear main seal. Theres steel billet on the high end, plus forged steel, malleable steel, and nodular iron (cast iron). Examples race camshaft and torque intake, or stock heads with a tall single plane intake manifold. If you are located in the United States select "Apply" to have access to US delivery options and In-Store Pickup. SBF. The cranks torsional action rebounds against the piston and rod as they ascend on the compression stroke. When it comes to mainstream 351C, 400, and 351M crankshafts, basic identifi cation numbers of 4M (351C, 351M) and 5M (400) and 1K (351M only) hold true as excellent means of identification. November 30th, 2022. of torque. I HAVE A XY GT FALCON AND WILL NEVER PART WITH IT. Igor a 1970 Mach 1 with shaker hood. Instead of controlling compression with a dished piston, Ford made the chambers large like an indoor football domed stadium. I did this back in the 90"s. 351w block. Eagle Specialty Products has its own unique approach to forged steel crankshafts. Apr 10, 2023, Crankshaft, External Balance, Forged 4340 Steel, 4.000 in. Theres a lot of scuttlebutt about 351C, 400, and 351M crankshaft identification numbers, but basic identification has never changed in all these years. The tradition V8 firing order. 2023 Chevrolet Corvette Z06 (Chevrolet) The 2023 Corvette Z06 trades the Corvette Stingray's 6.2-liter V8 for a 5.5-liter V8 that's more powerful, even without any supercharging or turbocharging . Stop by our booth in Indianapolois at the 2022 PRI show from December 8-10, 2022. Monday 3/6/2023 In 1975, Ford dropped the low deck 351C in North America, instead de-stroking the 400 to 351 cubic inches and calling it the 351M. In fact, Ford planned 500+ cubic-inches for the big block, which never materialized amid environmental concerns and the Arab Oil Embargo. $12,345.67. Shop Connecting Rods SCAT connecting rods are made from a 2-piece chromoly steel forging to ensure maximum strength and durability. A flat plane engine's crankshaft throws its pistons 180 degrees, creating a shape that from an aerial view would look a lot like a straight line. Estimated International Ship Date: A 351C crankshaft has a 2.750-inch main journal, which makes it a different crank than you find in the 351M, which has the 400's larger 3. . Apr 20, 2023 they are actual inventory from our shelves. Copyright 2023 by AUTOSALES, INCORPORATED Rotating Assemblies - SCAT Crankshafts - Redondo Beach, CA My Account The Leader in high performance internal engine components. Ie timing & heads. Marvin lost his battle with old age at 87 last year, but his legacy of great engines remains. In theory, the flat-plane design delivers a V-8 with less reciprocating mass, and superior breathing, which should make an engine lighter, more compact and capable of building rpms very quickly. if ordered today, Engine Rotating Assembly, Cast Crank, Forged Pistons, I-Beam Rods, Ford, Cleveland, Kit, Estimated USA Ship Date: Try this experiment: Mention four-valve (4V) Ford to a few fellow enthusiasts and see what discussion pops up. if ordered today, Estimated USA Ship Date: After our baseline, we replaced the Elgin CJ cam and 4V intake with a Comp XE284H cam and Edelbrock Performer RPM Air Gap intake. Mar 29, 2023 . The reason you want a steel billet crank is its raw strength. And that unique sound! Based on four decades of experience with this engine and the many people Ive seen build Clevelands, this is a crankshaft with a great reputation for durability, especially if you inspect and prepare it properly. 29/09/2022. This is a custom order part. The 351C became the darling of the performance industry from 1970 to 1973, nothing negative was written about the 351C during those years, there was no commentary about the intake ports being . The cross-plane design has one throw every 90 degrees at north, east, south, and west positions. $5 Off Your $100 Mobile App Purchase - Get the App. Some builders use engine oil, but assembly lube has staying power. May 9, 2023 It sounds more trustworthy than cast iron, but it is nothing more than nodular iron. The Edelbrock intake was actually designed for the smaller-port, aluminum Edelbrock heads, but worked well on the larger 4V heads. This 351C was shipped to Marvin from the Midwest with its share of issues. The cheapest way to increase compression is to use 351C dome pistons (Keith Black KB Performance Pistons KB149.030). BEST WISHES TO ALL CLEVELAND GEAR HEADS AND AS A SCOT LIVING IN AUS SINCE 73 WE LOVE THESE ENGINES 351 Cleveland/Windsor Stroker kit includes: 4340 Forged crankshaft (90% possible internal balance without adding heavy metal) Forged H-beam rods W/ 7/16 ARP 2000 bolts (Exclusive Centralign design) Custom forged CP-Bullet flat-top pistons; King performance rod and main bearings; CP (Mahle/NPR) ring set, 1.5MM, steel top ring, Napier 2nd ring . Flat-Plane V8s are commonly only used in high-performance engines, such as the likes of Ferrari. The more time involved to make a part, the more expensive it becomes. There is also the other vibrations that the flt crank produces that can cause things to break. The Aussie Cleveland head employed all of the great benefits of a well thought out headwedge chambers and the smaller 2V ports for a perfect combination of flow and quench. Even though the Cleveland 351 came from the small block family, few parts will interchange. Trick Flow has the broadest selection of heads in the marketplace engineered specifically for the 335 Series Ford middle-blocks. The aftermarket has a good selection of modern aluminum alloy Cleveland heads available at a reasonable price. The forged Probe pistons used for the build provided an 11:1 compression ratio with the closed chamber chamber (quench) heads. Stay Updated with Emails from Summit Racing. Seal, Ford, 408, Kit, Estimated USA Ship Date: If I am missing something please let me know. Hi, A friend / customer a few years back who ran a 3200 '66 Fairlane with a 351 4 V. Cleveland, a Ford Motorsports solid flat tappet on a 106 or 108 LCA, top loader @ 5.13's. Ran a best of 11.61 @ 121. His specialties is Panteras. Are the lifters for a small block Chevy? It was a 4.2-liter or 255 cubic inch variant of the 302 which had a smaller bore of 3.68 inches. A wide variety of displacement sizes can be built using these cranks as the foundation for a 351 stroker kit. Summit Racing can help. Despite the 335 engine family lasting until 1982, the 351C was only produced until 1974. Im done flogging the dead horse . Cleveland 300 hp cam they would discover what made those heads work , and yet be suprised it made peak power at 5,400 rpm , i am currently building one for a 69 Mach 1 i am using tbe aluminum speedmasger raised port 3v head with just a light port clean up and allot of combustion chamber work mostly removing the wall around the valve seat , cam will be a Lunati roller 231@.050 112 lobe sep .610 10:1 comp , port efi . Ports were either too small or outrageously large. In 1980, Ford introduced a new version of its small-block V-8 engine. Rotating Assemblies SCAT's sales staff will reach out to you to confirm your Rotating Assembly order and provide a lead time, which is typically 2-3 weeks. 351 cleveland flat plane crank. Is it just a repurposed small block Chevy part? For those unfamiliar with the fabulous Ford 4V, the question has to be, what exactly made the Cleveland so special? The cylinder bore spacing and head bolt patterns of Cleveland and Windsor heads are identical which makes the better flowing Cleveland heads a natural choice. It was an engine long on growth potential, but never grew any larger. It still runs to this day. 302 351 Cleveland 4 barrel 2v manifold in good condition. The 351C 4V motors, and even the smaller 1969 & 1970 Boss 302, offered head flow unmatched by any (regular) production small block Ford, Chevy, or Dodge heads of the period. The motor mounts on a Cleveland and Windsor are the same, the 351M is quit a bit different, 351c amd M have the same valve covers while the Windsor is the same as the 289,302 . 351-C 4V are not SBC and none of the math or approach to them is the same. 857 3558 $ - 302 351 Cleveland 4 barrel 2V manifold. $120. Diameter Main, 4.00 in. The 351C-4V head had terrific wedge chambers with good quench, yet with ports too large for street use. What makes the 351M and 400 different than the 351C is larger main and rod journal sizing along with the raised deck block. . if ordered today, Rotating Assembly, Competition, Forged 4340 Crankshaft, Forged Flat Pistons, 2 pc. The 351C, 400, and 351M crankshaft identification is 4M for the 351C and 5M for the 400. Forged steel crankshafts are typically made of 4340 hardened steel. Probe Racing supplied the small-dome, forged pistons, which also featured the necessary valve reliefs for more aggressive cam profiles. The forging is then heat-treated via a quenching process and allowed to cool before being machined into its final configuration. The forged pistons and reconditioned rods were teamed with a factory cast (polished and balanced) crank. After years of producing high-performance V8 engines - some normally aspirated and some turbocharged but all admired for their rumbling exhaust notes - the announcement in 2020 by then AMG boss Tobias Moers . Never miss a sale on new parts, tools, and more! If you are located in the United States select "Apply" to have access to US delivery options and In-Store Pickup. Thanks for the great article. May 8, 2023 If youre building a stock-appearing 351C, but want better performance, this is the head you want (though theyre becoming more scarce all the time). Excessive endplay beyond .010 inch is unacceptable because it adversely affects crank and rod/piston alignment. 351 cleveland flat plane crank . Stroke, 2.75 Mains, 351C, Kit, 2.0 out of 5 stars You can order this part by Contacting Us. Your email address will not be published. About | Contact | Terms | Privacy. Estimated International Ship Date: Enthusiasts get this mixed up all the time, but there is but one truth. Bryant Crankshafts Watch on ABOUT US Bryant Racing Home of the Crankshafts that Champions Choose As pistons and rods rise to compression/ignition stroke, oscillation becomes more intense, acting on not only the crankshaft, but also connecting rods and pistons. Others are made of 1038 steel, which isnt as pure as 4340, but still quite effective. To add insult to injury, you sometimes install rod bearings backward, which is failure before you even get started. (1), In Stock, Including at a Supplier. Stroker Cranks and Stroker Kits for the Ford 351 Cleveland, 393 & 408. However, there was also the new 429 and 460 cubic inch Ford 385 Series big blocks, which didnt weigh much more that had this displacement range covered. As expected of a healthy cam upgrade, both peak hp and torque occurred higher in the rev range, but the new combo only experienced losses below 3,300 rpm. The 351C has a 9.206-inch deck height. lol. Learn how your comment data is processed. If you do not find the small block Ford 351 crank you need, please contact us for assistance. The Cleveland 351 is between a small block and a big block. Aside from the obvious stress, there are other loads such as oil pump and distributor, which also contribute to twist. Estimated International Ship Date: You spend so much time focused on journal surfaces, oil hole chamfering, and balance you forget to examine fillet radius and the bearings important relationship with it. Once the forging is trimmed and machined, it gets nitrided for good surface hardening. When shopping for stroker kits, just keep in mind that Windsors and Clevelands use different piston types and will need to be specified when ordering parts. This keep journal surfaces hard and less inclined to wear. uk religion statistics 2020 pie chart. Estimated International Ship Date: The 351 Cleveland story is one of the most befuddling in Ford history. The machine work included boring and honing the block to accept a fresh set of .030-over, forged slugs. We finished up the short block with a reproduction (hydraulic flat-tappet) 351 Cobra Jet cam profile courtesy of Elgin cams. You can comfortably turn your journals to .020-inch undersize and still have durability. You may also cruise the online auctions for a vintage 5.0L roller block (F1AZ-6010-B). Estimated International Ship Date: This looks like two four cylinder engines that have been joined together at the crankshaft. All 335-series Clevelands are 28-ounce offset balanced. 4V Ford Cleveland heads NEVER had 4 valves. Theres also the harmonic balancer, which acts as a shock absorber for crankshaft twist. + The flat-plane crank depicted in the excellent animation has its throws arrayed in an up-down-up-down (UDUD) configuration, the same type used in Ford's recent Shelby Mustang GT350 V8. Essentially, it was a scaled-down version of the 302. The 351C 4V heads were also treated to a new set of stainless steel (intake and exhaust) SI valves, with the more-common single grove keeper to replace the factory multi-groove versions. On the right is a 400 with a 4.000-inch stroke and 5M marking. Ford could have grown the 400 to 435 to 450 cubic inches with less weight than a big block. Results 1 - 20 Manley SBF 4.100 Stroke 4340 Forged Crankshaft 351C & Windsor 2.750 Mains - 190340. The article is correct. In North America, it was only in production for four years (1970-74), yet it became the hotrodders mainstay in Australia well into the 1980s. Ford 351 Cleveland engine - 10.2:1-C/R. Your email address will not be published. The Cleveland engines were never factory equipped with a steel crank. Thanks. Cubic Inch. The exhaust pulses in the headers are evened out. Its advantages are far greater than the sum of its parts. If you take a small hammer and tap a forged crank, it rings like a bell with a long resonance afterward. Meanwhile, in Australia, Ford continued with great improvements in the 302 and 351C engines. Youre right, Mike+Brown. Cast Crank shaft with 90% nodularity; . Estimated International Ship Date: Shop ROTATING ASSEMBLIES A flat plane crankshaft has the potential for significant weight savings to optimize a motor's moment of inertia and more even firing to benefit the exhaust stroke, allowing for more revs/horsepower. Available in 3.48 to 4.125 strokes, weigh 46 to 50 pounds. Scat manufactures some of the lightest cranks in the industry, which is what racers want. The 11.0:1 Probe pistons were designed for use with the stock connecting rods. As its name suggests, a Flat plane V8 crankshaft has all its crank pins in a single plane. The flat-plane crankshaft from Ford's 5.2-liter Voodoo V-8. Read this: Whats the Difference Between a Ford 351 Windsor, Cleveland, or Modified Engine? It does not mean Brinell tested. of 38, Engine Rotating Assembly, Forged Crank, Forged Pistons, H-Beam Rods, Ford, Cleveland, Kit, 3.0 out of 5 stars Radiuses of both bearing and fillet must be identical for perfect mating and without stress issues. I want to keep the shaker filter. These crankshafts will fit Ford and Mercury 351w and 351c engines and stroker engines built using these OEM engines as foundations when using OEM or aftermarket blocks that use the 2.750 inch diameter 351c size main journals. Ships In a Few Days. M echanically, the flat-plane crank V8 is essentially a pair of inline four-cylinders fused at the crankshaft. Searched everywhere about port matching airgap or most modern manifolds to the 4 heads and found nothing. Regardless of how you look at this dynamic, cyclic issues affect crankshaft life. Also I believe a flat plane crank is not as balanced as a 'normal' crankshaft and will introduce more . The answer lies in the massive head flow offered by the 4V heads. Juechter said that the team spent around a year developing the aural. Estimated International Ship Date: These billet crankshafts are midway through the machining process. Whats the Difference Between a Ford 351 Windsor, Cleveland, or Modified Engine? The Basic Flat Plane Crankshaft Stevie's Crazy Garage 1.23K subscribers Subscribe 1K Share 113K views 7 years ago This video uses rendering techniques to explain the basic concepts of a flat. We have taken the guess work out of getting the most bang for your $$. Mar 21, 2023 The LT6 is comprised of a two-piece aluminum block mated at the crankshaft centerline and topped by aluminum cylinder heads. 0:00 / 2:32 Shelby GT350: Ferocious Flat Plane Crank Sounds DtRockstar1 79.6K subscribers 87K views 3 years ago We capture the sounds of a 2018 Shelby GT350 and the high revs of the flat plane. Privacy Policy Copyright 2023 MolnarRods.com All Rights Reserved, 351 Ford with 2.100 small block Chevy size rod pins, Ford 351 with 2.100 small block Chevy size rod pins, Ford 351 stroker crankshaft with 2.100 small block Chevy size rod pins, 351 stroker crank with 2.100 small block Chevy size rod pins, Ford 351 stroker crank with 2.100 small block Chevy size rod pins, Nitrided main and rod journal surfaces for superior wear resistance, Precision machined to extremely tight tolerances, Material properties are monitored closely to insure optimum performance, Counterweight placement designed for improved crankshaft performance, .125" radius on both the connecting rod and main journals for increased strength, Precision ground and micro-polished journals. Stock Crank and rods, 30 over trw 2348 pistons, OC heads cut .060 59cc, Ported intake and exh. of torque at 3,800 rpm. The short stroke delivered a deck height some 23 mm (0.9 in) lower than the standard Corvette's LT2 V8. The fillet radius where crank journal meets the counterweight is the most common failure spot between journal and the rest of your crank. It was first a 400 cubic inch deal in the early seventies. To show the stock 4V heads had plenty of offer, we first ran the Cleveland with the factory, iron 4V intake manifold and 750 Holley carburetor. Where other Ford V-8 engine families had both cast and steel crankshafts, the 351C was produced in cast only. Mar 16, 2023 Including: Camshaft, Lifters, Timing cover, multi keyway timing set, High volume oil pump, K&N oil filter. The 351C crank is marked with an identification number of 4M or 4MA. We have rebuilt tons of customer engines over the years that were all wrong and had parts that didn't work together. International Customer Options|In the United States? Stay Updated with Emails from Summit Racing. Why didnt they do a test with the stock intake manifold and the cam upgrade? Not sure which Ford 351 youve got? Hey Frank, I cant speak for Richard Holdener but Clevelands are still my favorite engine to build and your question is a good one. Estimated International Ship Date: Crankshafts and camshafts are ductile or nodular iron (ASTM A339) at 310 on the Brinell hardness scale. ROUSH is still proud to offer custom engine building, as well as complete crate engines and crate engine components! In short, it is a crankshaft that makes it part of an automobile engine. Cleveland crankshaft identification is easy and based on codes stamped into the first counterweight. What this means is that they respond very well to other performance mods, like a healthy cam and improved induction system. 351 Cleveland Power kits. Click the button below and we will send you an exclusive deal on this book. The 4M crank has a 3.500-inch stroke and a 2.750-inch main journal. Written by George Reid and Republished with Permission of CarTech Inc. Codes 4M, 4MA, or 4MAB indicates a 351C or 351M crankshaft with a 1.750-inch throw or 3.500-inch stroke. With 526 horsepower and a soundtrack like this, it's easy to see why it has been attracting attention. A good rule to follow is to machine the crank journals to the bearings, and swap bearings around to get optimum clearances. If you are an international customer and would like to change the currency that prices are displayed in, you can do so here. A steel crank has smoother surfaces and wide parting lines due to the violent forging process. The 351C has smaller 2.750-inch main journals, which means you would need the journals turned down by a competent machinist. ( 1 ), Street & Strip, Series 9000 Rotating Assembly. Cast Stroker Cranks and Forged Stroker Cranks and Kits. Pistons - 351 crank, 302 rods - Cleveland - OzFalcon - Ford Falcon Owners Club All Activity Home Technical V8 Tech Cleveland Pistons - 351 crank, 302 rods Sign in to follow this Followers 2 Pistons - 351 crank, 302 rods By Mr Polson, April 1, 2014 in Cleveland 1 2 3 Next Page 1 of 3 Mr Polson Tourist Administrators 10,043 8,343 posts The 351M is a taller decked Cleveland block with larger mains. The flat-plane crankshaft in the Ford Shelby GT350 Mustang's 5.2-liter V8. The billet crank begins life as a cylindrical steel ingot, which enters a labor-intensive process of many machiningsteps before it looks like a crankshaft. Follow along with the entire process here: Richard Holdener is a technical editor with over 25 years of hands-on experience in the automotive industry. You can use the social sharing buttons to the left, or copy and paste the website link: https://www.diyford.com/ford-351-cleveland-engines-crankshaft-guide/. Fun and dependable 67 FB Mustang, Street Car. 50 pound Legal with rounded leading and trailing counterweight edges. I believe Marvin used a small-block Ford spider. In other words, youhave a broader oil hole surface area at the journal, which increases volume. You can also visit the ROUSH Competition Engines direct website. $ 1,159.00 Each - Free Shipping. The 400 saw steady use in passenger cars through the late 1970s. Cleveland Show: Adding Nearly 100 HP to a Free-Breathing Ford 351C. Fueled by Jack Roush since 1976, ROUSH has been building some of the best Ford-based performance engines in the world. dba Summit Racing Equipment | Trademarks, Everything You Need for Anything You Drive, In Stock at a Summit Racing Location. Filed Under: Ford 351 Cleveland Engine, Ford Tech Tips, 2023 DiY Ford. Apr 10, 2023 Re: Remember using a Cleveland crank in a Windsor? If you are a professional racer that little tiny extra bit might be what you need to win a race. Mar 20, 2023 This means you can machine your Clevelands crank beyond .010-inch undersize without concern for failure, especially if youre building a street engine. Cast is good for anything up to 450 hp. Both designs attach two connecting rods to each throw and their blocks have 90 degrees between cylinder banks. Cant wait. DONT CHIME IN ON CONVERSATION YOU OBVIOUSLY need to do some of your own proof reading Mr negatively. It mentions 4v and says 4 VALVE.. Lol cast heads have a tiny 4v on the corner of the head. 351C/425HP Balanced Crate engine with Aluminum heads. May want to check with Comp Cams or Crane on this. However, there is a second, more traditional flat-crank design with the journals arranged up-down-down-up (UDDU) like a familiar inline four. There are three factory nodular iron crankshafts identifiable by markings, stroke (throw), and main journal dimensions. If you liked this article you will LOVE the full book. Fords 335 Series Cleveland existed in two forms in North Americathe low deck 351C and the raised deck 400 and 351M. MISCELLANEOUS In addition to the Chevy, Ford and Dodge offerings, we have numerous other crank programs to build what you are looking for. Spinning the upgraded rods and new forged pistons was a cast 351C crank. For many, particularly the boys down under, 4V means ONE thing, Cleveland performance. Leib breaks it down by saying the flat-plane crankshaft offers better cylinder head breathing symmetry and scavenging. My Blog 351 cleveland flat plane crank Seal end gaps should be staggered away from main cap parting gaps. Automakers engineer tremendous strength into even the most modest cast-iron crankshafts. Sometimes a nick renders a journal unserviceable if it is deeper than the minimums allow. The Cleveland had the best flowing heads for a SB Ford before aftermarket heads, thats what made them great motors pre 1990s. Ford's decision to terminate 351C production was rooted in scaling down production costs. Codes 4M, 4MA, or 4MAB indicates a 351C or 351M crankshaft with a 1.750-inch throw or 3.500-inch stroke. The engine was produced in displacements of 4.9 L (302 cu in) and 5.8 L (351 cu in) for use in the . Great comments! Once all machining is complete, the forged crank is heated to 400 to 600 degrees F to relieve stress and carefully allowed to cool. Ships Tomorrow. using a 6.125 chevy rod and chevy 383 piston and add the. Unported, just minimal valve pocket clean up on 4 V. Cleveland cylinder heads. Estimated International Ship Date: You can order this part by Contacting Us. Given the flow rates, even this modified 351C was just scratching the surface of what OG 4V heads will support! The Right Stuff between seals and grooves is also beneficial. Main thing is a detailed inspection and good prep work going in. if ordered today, Crankshafts, Forged-43, 2-piece Seal, Forged 4340 Steel, 3.850 in. $5 Off Your $100 Mobile App Purchase - Get the App. The original 4V, 2-bolt, 351C was disassembled and treated to some first-class machine work by L&R Automotive. Apr 20, 2023 The 4.000 stroke crank is very popular for building a small block Ford 408 stoker engine. EVERYONE MAKES MISTAKES LOL, LETS FOCUS ON THE SOLID INFORMATION AND THE FACT THAT RICHARD IS As a flat-plane crank is, essentially, two four-cylinders sharing a common crank, the exhaust sound is quite unique. When I see 4V heads are not good the street or low end I immediately know that person does not understand 351-C 4V. Most of the better ones use forged pistons, rods and crankshaft that has smaller 2.750, 351C size main bearing journals for longer bearing life. When you look at the two types side by side, the difference in size is quite clear. Rust scores new bearings. Street Clevelands do not need a steel billet crank, which is purely a race piece for extreme-duty use.