Small Block Stroker Kits
Street Kit 408-416 cubic inch
This is the kit we build our SB Street Krate engine with. We start with a cast SCAT 4” stroke crank, SCAT 6.123 long forged I-beam connecting rods w/bronze wrist pin bushings, Keith Black Hypereutectic pistons, Michigan 77 rods and full groove main bearings, and plasma moly piston rings. The rotating assembly is then internally balanced to a tolerance of less than one gram. This kit is recommended for applications under 500 HP and applies to 340 and 360 blocks only. Bore sizes available include 4.030, 4.040, 4.060, and 4.070.
318 kits require a forged piston and filed to fit rings for an additional $250.
340 and 360 based kits are offered with optional forged pistons (bore sizes up to 4.080) for an additional $250.
Performance Kit 390- 416 cubic inch
These kits are for Hot Street or Bracket Racing. Assemblies are capable of 500 -800 HP. These kits include a 4340 steel 4” stroke crankshaft, 6.123 4340 steel H beam rod with ARP 2000 bolts and 0.984 wrist pins, forged Icon pistons, chamfered race bearings, file to fit plasma moly rings. The kit is completed with a competition internal balance. Available in pump or race gas compression for 340 and 360 blocks in bores ranging from 4.030 to 4.080. 318 blocks are available in bores ranging from 3.940 to 3.970.
Competition Kit 416- 450 cubic inch
We use this kit in higher RPM combinations (over 7000 RPM) or in nitrous and or ProCharged applications. This particular crank has either a 2.000 or a 2.100 rod journal for a great selection of bearings. The kit includes 4340 steel Molnar Technologies 4” stroke crankshaft (340 main size ONLY!). 6.300 long 4340 steel H beam connecting rods, custom Ross pistons (any configuration), chamfered bearings, file to fit plasma moly rings, competition balanced.
Upgrade kit to 4.125 stroke forged Molnar Technologies crankshaft (requires oil pump modification to clear additional stroke) this will easily build a 450 cubic inch engine for an additional $200*.
*Aftermarket block is required for bore sizes larger than 4.100.
Big Block Stroker Kits
440 Stroker Kits
All of our Muscle Motors kits feature our private label crankshafts. As stated in the opening statement about stroker kits: we strongly recommend micro polishing of any (except K1 and Compstar) Asian crank. As an option any of our Big Block kits can be upgraded to a K1 crankshaft for an additional charge. The K1 cranks do not require micro polishing to remove taper.
440/446: 3.75 stroke x 6.768 rod.
This is really not a stroker kit but a stock stroke replacement rotating assembly. The standard kit is offered with a stock crank & rods and cast hypereutectic pistons. Plasma-moly piston rings, Clevite 77 bearings and balancing are all included. Upgrades are available.
440/500: 4.15 stroke x 6.76 rod.
This is the kit that started it all. Forged dished pistons are required for pump gas compression. It is available in 0.030, 0.040 & 0.055 bores with quite a few different compression ratios available. This kit will require minor bore notching so that the rod bolts do not interfere with the block. You will also need to clearance the boss that the oil pick-up tube screws into. Kit comes competition balanced with Plasma moly rings and chamfered bearings. A tried and true combination for the ages.
440/512: 4.25 stroke x 7.100 rod.
This is the kit that comes standard in our Killer Krate engine. The kit will actually make a 505 cubic inch motor in a +0.030 bore. Again forged dished pistons are standard. The 4.250 stroke is made with a 2.200 rod journal. This smaller journal does not need bore notching and only minimal work to the oil pick up boss. The long rod makes for a very light weight piston. Plasma moly piston rings, chamfered performance rod and main bearings along with competition balancing of the rotating assembly are included. We do have many choices for bore and compression available.
440/525: 4.375 stroke x 7.100 rod.
We’re gettttiiinnng biiiggger! This is a great combination for heavier vehicles that still want to maintain an internal oil pick up tube. Station wagons, trucks, B and C bodies with full interior are common recipients of this stroker combination. Lots of stroke (read: torque) to motivate a 3800+lb Mopar. Chamfered bearings as well as file to fit plasma moly rings are included in the balanced rotating assembly. Forged 0.030, 0.040 and 0.055 over pistons are available in dished and flat top versions.
440/540: 4.500 stroke x 7.100 rod.
For stock blocks this is the largest stroke that we build. It will require bore notching, oil pump boss clearancing AND an external line oil system. If you want the max out of your stock engine block and don’t mind the external line oil system, this is the kit for you. The 4.500 stroke works great for Pro Street cars that have big tires and tall gears. This kit, like all of our kits is balanced and comes with file to fit rings and proper chamfered bearings. Flat top and dished forged pistons in 0.030, 0.040 and 0.055 over are available.
King Krate/ 4.500 & 4.750 stroke x 7.100 rod.
These kits are for aftermarket (4.500 and bigger bore) blocks only. The 4.500 x 4.500 make a 572 cubic inch motor. The 4.75 stroke x 4.500 bore makes a 604 cubic inch (622 cubic inch in 4.560 bore). These kits are what we use to make our King Krate pump gas engines. Ross dished forged pistons are standard equipment along with plasma moly rings and chamfered bearings. As with all of our kits, they are all meticulously balanced on our computerized Hines crankshaft balancer. There are many upgrades for the kits depending on application.
440/572 Only: $2799
440/604 & 622 only: $4599
400 Stroker kits
400/451 cubic inch: 3.75 stroke x 6.76 rod, 4.375 bore 1.320 CH piston.
One of the original stroker kits for big block Mopars. These kits are nothing more than a 440 built with a really light piston. 3.750 x 6.760 (440 stroke and rod) but because the block is 3/4”shorter, the piston is 3/4” shorter and literally half the weight. We use a new 4340 steel crank and rods with your choice of forged pistons. Rings, bearings and balancing included.
400/470 cubic inch: 3.91 stroke x 6.700 rod, 4.375 bore 1.320 CH piston.
This is one of those kits that works better than it should. When using stock port window cylinder heads (factory, Edelrock RPM, Stage VI) this is the PERFECT combination. This engine has a good amount of cubes, super light weight rotating assembly, great rod ratio, and is just a dynamite combo.
400/511 cubic inch: 4.25 stroke x 6.535 rod, 4.375 bore 1.320 CH piston
This is my personal favorite combo for competition. These kits work really well with bigger port heads such as 440-1’s or B1’s. In a 400 block I don’t build anything bigger because there just isn’t any point in a stock block! This combo has a piston with a 1.320 compression height. What that all means is that it stops the piston at zero deck on an un-machined block.
383 Stroker Kits
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. The 383 kits come with forged Ross dished pistons, chamfered bearings (we have chamfered 383 & 400 main bearings), file to fit plasma moly rings and competition balancing for a truly ready to go kit when you receive it.
496/383. This combination actually makes a 489 cubic inch motor in a +.030 bore and 496 cubic inch motor 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. With a 4.25 stroke, 6.535 and a 1.307 compression height dished pistons (for pump gas compression) this is ideal for someone building the ultimate sleeper. Our 1.307 compression height piston also stops well below an un-machined stock block deck surface. These Ross pistons along with chamfered rod and main bearings and competition balancing finish the kit.