All of our stroker engine blocks are prepared the same way. First they are jet washed to remove all dirt and debris. A jet washer is like a giant dishwasher. It sprays a caustic solution that is heated to 180 degrees. This high pressure solution dissolves dirt, grease and oil leaving a clean ready to machine surface. Then the blocks are magnafuxed to make sure there are not any cracks or defects. Then the blocks are sonic checked to make sure there are no core shift issues and all cylinder walls have adequate thickness in all directions. (SIDE NOTE: there is a common misconception that blocks made after 1974 are “thin wall” blocks. THIS IS A COMPLETE FALACITY. I have sonic tested 1978 blocks that are some of the thickest blocks I have ever checked! The only real way to know if you have cylinder walls strong enough to make over 550 HP is to sonic check them. Pre 1972 blocks are made with a higher nickel content cast iron but can be thin. I believe you must sonic check any block to be used in a high performance application. That is why sonic checking is standard procedure on all engine blocks machined at Muscle Motors). After we have determined that we have a good core we then debur the block of all casting flash and enlarge the oil galleys that supply oil to the main bearings. ARP main studs are installed and the main bearing bores are align honed. This ensures not only consistent bearing sizing but perfect alignment of all bearing bores. We then bore and hone the cylinder bores with deck plates to the first oversize (usually +.030 or +.040). Next, we machine the deck surfaces square and parallel for an ideal gasket sealing surface. The next procedure is to grind the block for stroker clearance. Not all blocks need this clearance but we figure it is better to have it and not need it, than the other way around! The next step is to measure and size all of the cam bearing bores for perfect cam fitment every time (see side bar). Lastly the oil pick up is then enlarged to 1/2” and then block is again jet washed a final time. Cam bearings and brass freeze plugs are installed and the block is painted in red oxide primer.
All of our stroker short blocks are professionally assembled by someone with AT LEAST 20 years experience in engine building. Please look at the “stroker kit” section of our web site for specific details on how our stroker kits are truly “ready to assemble” as delivered.
Wrist pin sizing is checked on the rods and pistons and are then assembled. Bearing sizing of the rods and mains are checked and recorded on a build sheet. Next, the ring end gaps are checked and filed to specific clearance again recording this information on a build sheet. The crank is then installed followed by the rods and pistons. The stroker short block, is now complete and ready for shipment or have additional parts added depending on each customer’s individual needs. Build sheets are available for ALL engines assembled by Muscle Motors.
Stroker Short Block combinations:
We offer two combinations for this long forgotten big block. 383’s work exceptionally well in hot street applications up to 575 HP. The small bore (4.25 from the factory) is the reason people have shied away from this block for performance applications. In the last 8 years with the increased availability of good flowing/cost effective heads and modern cam technology, 550+ HP is easily attained even with the small bore size.
We do not offer a 3.75 stroke combination for a 383 for a few reasons. One: why build a 431? We’re building BIG INCHES here! Second the 3.75 crank that is available does not fit in the 383 block without modification to the block or crank. All too much work for only 431 inches! Both 450” and 496” kits only need minor bore notching for proper stroker clearance.
450/383. This is a version of the tried and true 474/400 combo we pioneered back in the 80’s. Back then we would offset grind cranks to a 3.9 stroke with a 2.200 rod journal. We would then use a 6.535 long GM style rod and those kits worked AWESOME! Today we just have the cranks made new out of 4340 heat treated steel and use a similar, but slightly longer 6.700 long rod. This combination is ideal for someone looking for a little more out of their 383. Stroker kit professionally installed into a Muscle Motors prepared block $4199 (outright, no core charge)
496/383. This combination actually makes 489” in a +.030 bore and “496” in a +.060 bore. We just call it 496” because our original welded stroker kits that were the first on the market back in the 80’s were called “496 Stroker Kits”. This combination is a TORQUE MONSTER. 4.25 stroke, 6.535 and a 1.307 compression height dished piston (for pump gas compression) and is ideal for someone building the ultimate sleeper. Stroker kit professionally installed into a Muscle Motors prepared block $4199 (outright, no core charge)
In my 22+ years experience, the 400 block is THE best wedge block for performance engine builds. There are number of factors that make me say this. First, bore size: the 400 has the biggest starting bore @ 4.340. Bigger bores unshroud the valves and allows the cylinder head to flow more air. As we all learned in “engine building 101”: the more airflow you have, the more power you can make! 2) The short deck height makes the cylinders more stable, and the block itself fits better in tight fit applications. The shorter deck height also means a shorter/lighter piston. Factory blocks don’t really like a lot of stroke (two bolt mains) so we try to limit performance and race engine builds to a 4.25 stroke. Limiting stroke helps minimize main cap walk and improves block durability. Since we don’t run very large stroke, we can then use a 6.535 long rod and a 1.300ish compression height piston. This creates a combo with a good rod ratio, short/light piston without having the wrist pin intersect the oil the oil ring and a piston that is tall enough to accommodate any valve pocket depth and or ring package 3) main size: the 2.625 size main bearing require less oil to maintain a hydrodynamic wedge (this is the “wedge” of oil that separates the crank from the bearings) and the smaller main size also leaves more material in the block around the main studs/saddles. This is important because the block is the weakest link when building a performance engine in a stock block. When we build a high performance 400 or 440 block we will use a main stud girdle for power ranging from 650-750 HP. For power levels over 750 HP we will upgrade the main caps themselves as well as at least a partial filling of the water jacket with cement for bottom end stability. Other than a somewhat limited availability of good core blocks, the 400 is my favorite engine block to build.
451/400 One of the original stroker combos for the Mopar faithful. This combination was created by taking a stock steel 440 crank and grinding the mains .125 undersized (std 400 size) and then machining the counter weights to clear the 400 block. Nowadays we just have a new crank made out of 4340 steel that has heat treated bearing surfaces that just need to be balanced before it is ready to drop in. 3.75 stroke, 6.76 long H-beam connecting rods with .990 wrist pins. Great for street or race applicatons. Stroker kit professionally assembled in a Muscle Motors prepared block $3949
470/400 Another tried and true package that works exceptionally well with stock port window cylinder heads. It has enough stroke to get a big car moving without being too big for factory, Stealth, Indy EZ or Performer RPM ports. Yes these heads will work on bigger engines but 470” package is one of the combinations that “works better than it should” because everything is proportioned just right for a stock port window! Stroker kit assembled in a Muscle Motors prepared block: $3949
511/400 Awesome combinations!! Rev’s like a small block and tons of stump pulling torque! In a pump gas application this package LOVES big port/Max Wedge style heads. Big Port Indy EZ’s, 440-1s and even the original B1 (for race only applications) are perfectly at home with a 511” combination. It is not unusual to install a girdle or aftermarket caps on these combinations. Stroker kit professionally assembled in a Muscle Motors prepared block: $4099
Muscle Motors main girdle installed add $300
Aluminum or Steel main caps installed add $750
The 440 block
The 440 bock is the grand daddy of all Mopar stroker engines. It has lots of room for long strokes and long rods. It is also the deck height required for most “cool guy” aftermarket manifolds. 6 packs, long rams, cross rams and inline 2x4’s were all originally designed for this 10.725 deck height block. Most people with a hot rod Mopar usually have started with a 440 so all of you support components (distributors, headers, intakes, etc) are all designed for the RB block. Because of this reason we have built more 440 stoker combos than ALL OTHER BLOCKS COMBINED! Anything from stock stroke 440’s up to 540” engines can be made to fit in a 440 block. I do not recommend anything bigger than a 4.500 stroke in a 440 block for a few reasons. Mostly because the two bolt mains can only take so much stroke! 80% of the 440 strokers we build as 4.15 or 4.25 stroke engines. We can make over 700 HP on pump gas with 505”! If you can’t get it done with 505”s, you need to reevaluate your combinations. There is no “silver bullet” or “automatic fix” with bigger cubic inches. That being said if you have a VERY heavy street car, station wagon or truck or you just want the rowdiest street engine you can build, I will build you a 520” or 540” in engine in a stock block. For the most part (in racing applications) long strokes (4.375, 4.5, 4.75) really require an aftermarket block with cross bolted mains and big cylinder bores.
440/440: For those looking for an updated replacement of what they already have. Stock stroke, stock rod rods, and cast Hyperutctic pistons. 9.5:1 compression. These short blocks are fully machined as described above but retain factory mains bolts. This block with a balanced rotating assembly professionally installed is $3499
493/440 This is the original 496 stroke kit. 4.15 stroke, 6.76 long H-beam rod, and a dished piston makes up this original 500” stroker kit. Available in a wide verity of bore sizes and compression ratios to suit any application $4149
505/440 This is the most up to date stroker kit for 440’s. 4.25 stroke w/a 2.200 rod journal. This requires minimal to no stroker clearance, 1/2” internal oil pick ups fit w/no modification of the pick up tube. The 7.100 helps make a very short (but stable) and light weight piston. This is the kit we now use to build our tried and true “Killer Krate” engine combination. Professionally assembled in a Muscle Motors prepared block $4199
520/440 This is a slight longer stroke combination and is the biggest stroke we recommend running with an internal oil pick up. 4.375 stroke w/2.200 rod journal, 7.1 rod and again a nice short lightweight piston. These work very well in 4000ish lbs street cars. The longer stroke help give a little more grunt to get you land yacht moving. Professionally assembled in a Muscle Motors prepared block $4199
540/440 Actually a +.030 block makes a 535” combo. A +.055 makes a 543”. I always though 540 sounded cooler! This is a BIG boy when it comes to stroke. 4.500 and even with a 2.200 rod journal you should run a external oil line system. I also caution against using these in race only/higher applications in a stock block. Big heads, big compression, roller cams and 6500+ shift points is a GAURENTEEED recipe for a failed engine block!! The longer stroke does gives you stump pulling torque, great for a 4x4 or a Pro Street car with very tall tires and a tall gear. The long stoke is a lot to hold on to for a 2 bolt main block but as long as you keep the RPM’s under 6000, you should have very good service life. IF you have an after market block like a Mega block or a World block that is capable of a 4.500 bore, this kit will make 572 cubic inches!!! Stroker kit professionally assembled in a Muscle Motors prepared block. $4199 (external oil system required)
Muscle Motors main girdle installed on any 440 short block add $300
Aluminum or Steel main caps installed add $750
“KING” Short block 540”, 557”, 572”, 605”, 622” Once your budget allows for an aftermarket block, the cubic inch options change immensely! I don’t believe there is a point in building REALLY big engines in stock blocks. Conversely, there is really no point in building smaller engines once you purchase a performance engine block! The type of cylinder heads you have will be the biggest determining factor on “how big” you should build. If you have a set Indy EZ heads then I would build a 540 or a 572. If you have a set of B1’s I would build at least a 605! Either way we still use our Muscle Motors brand crank and rods. In any application up to 1000 HP these components have worked flawlessly. Above 1000 HP we recommend upgradeing to a better crank and rods. Certain engine combinations will require a custom piston (at an additional fee). A Muscle Motors stroker kit professionally assembled in a Muscle Motors prepared World Products iron block start @ $5299.
World Aluminum block add $3200
Indy Aluminum block add $2200
Billet Aluminum rod (by R&R) upgrade add $750
Callies forged crankshaft upgrade $1200
Callies Billet crankshaft upgrade $2400
R&R billet aluminum connecting rods add $750
Oliver connection rod upgrade $1150
Hellfire rings for nitrous or forced induction add $200
Coated engine bearing upgrade add $125
Bush lifter bores (not required on World Aluminum block) $650