I've got a few questions about building a stroker motor, mainly about what crank to use. First of all, what are the differences between a 383 crank that I might buy from Summit, and a 400 crank? The only difference I know of is the size of the main journals. So if I had a 383 crank I wouldn't have to get the block machined out for a larger journal, right? The next issue is balancing: I know the 400 crank is externally balanced with the harmonic balancer and the flywheel/flexplate. And I've heard there might be issues of what flexplate to use if and when I try to bolt it up to a T56. I've read something about how I might possibly be able to convert it to all internally balanced. How exactly do I do that? And if I do manage that, but it is still a 1piece rear main, isn't it still partly balanced by the flywheel or flexplate?

 

If you use a GM 400 crank the its got to be cut down to fit a 350 and unless you get the offset pistons the pushrod geometry will be screwy causing premature engine failure.
There are many places that make stroker cranks to go either way. If I was you, I would look into the $899 cast iron crank with rods and pistons from iron eagle (through summit) If I remember right they want over 1k for the 1prm so It would probably be easyer to buy a rear main seal adaptor or get a builder 2prm from the junk yard. I think the adaptor is $150 but you could probably get a builder short block or just a block from a machine shop for that price also. Any crank shop should be able to ballance your flexplate to go with a stroker crank.
SSC

 

my stroker is almost done and I went with the steel crank internally balanced. the only thing U have to be carefull of with an internally balanced crank is that it needs to be a good casting or forged piece from the start. balancing a **** crank can be VERY, VERY!!! expensive. U R better off to spend the money on the good parts from the start. I am putting mine in a 4 bolt main 1-piece rear block from a newer chevy truck (i think that's where it came from, my mechanic picked it up for me for $125). you don't necisarrily need the 4 bolt over the 2 or the once piece over the two, some people prefer the 1 piece and others the 2, the only thing with the 4 bolt is it can hold higher and more prolonged RPMs plus more power. I have heard around that the one piece is a better block and is less prone to leaks, but I am no pro and don't really know to be honest, the only thing with the 1-piece, is that it is going to be an 87 or later block (i am pretty sure on that one) and the 87 and later blocks are already set for a hydraulic roller cam over the flat tappet cams, which could save you the conversion cost later on, even tho, hydrolic cams are more expensive from the get-go. oh well, I think i have said enough. good luck. . let us know how it turns out, I can't wait for mine, bout 10 more days.