383 Stroker

They can be made bigger, but it is a waste of effort, and requires a big dollar crank. Not to mention the oil system mods, and really bad side loading of the pistons. Like they said, loose the six pac rods. They are way too heavy and no stronger than std LY 440 rods because of the rod bolts and the parting area of the rod and cap. You can offset grind a std 440 forged crank to 3.90". It requires using a chevy sized rod journal. As Mike said, 440source.com was working on a special rod made for this application. The rod needs to have a thicker big end than a chevy rod, to keep the side clearance reasonable (not in spec, but reasonable). I think they are available now..Go check the website. You will also need a special piston I think. The kit may be the best way, but I dont think the $1400 special will work in a 383. I'd get a 440 block. Any 440 block will work, dont pay more for a six pac or "HP" stamping. There is no difference, as long as it's not cracked, and can clean up at a +.030 overbore. A 400 would be my first choice for the 440 crank deal. A 440 block with the 440source kit can go 500+.