Some info from Muscle Motors on their stroker kits for 400 blocks.


400 Kits

400/451”: 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 noting more than a 440 built with a really light piston. 3.75 x 6.76 (440 stroke and rod) but because the block is 3/4”shorter, the piston is ¾” shorter and literally ½ the weight.


400/470”: 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. Good amout of cubes, super lite weight rotating assembly, great rod ratio, just a dynamite combo.



400/511”: 4.25 stroke x 6.535 rod, 4.375 bore 1.320 CH piston.

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 unmachined block.