building a 383 Stroker with Factory parts help needed

Stock 383/400 main journal size is 2.625", 440 main journal size is 2.75". So grind the 440 crank main journals .125" to the 383 size of 2.625. Then use stock 440 rods, and buy pistons. That's the cheapest way to do it. Or you can use the 383 rods if you already have them. I prefer the longer rod, but some guys like the shorter rod. Just be sure to buy the correct piston for the rod you are using. You may have to ship the crank out to have it ground. Pistons are about 450 to 600. If you are using open chamber heads, you can buy KB quench dome pistons from Summit. Then you get into piston dome to head clearance considerations. Plan it all out on your computer, then go for it!

Get the block decked and measured BEFORE you buy gaskets or pistons. The last three 400 blocks I've had cleaned up square at 9.960, 9.965 and 9.965. With a steel rod, I'd expect a .035 or .040 gasket to be the right setup once everything is machined, but it all depends on the measurements. S/F....Ken M

I used a .020 gasket, with .015 deck clearance, steel 440 rods, closed chamber heads, and that motor ran Great! Really good throttle response, due to the tight quench .

Tight quench/squish is good for detonation resistance and fuel/air charge agitation. It has value, throttle response is unrelated, mostly due to high port velocity, which comes from dynamic compression (static compression and cam timing) and intake system volume.

Gary, your engine sounds like it was well built, I'm not arguing. S/F....Ken M