I apologize for bump the old topic, but I have some interesting observations that I would like to share, maybe this will help someone in the future because once I was on the lookout for useful advice
They sell kits for what you were thinking of doing. It would give you alot of low end torque. I heard good things if done correctly. Compression ratio and type of pistons is key. I'm pretty sure you basically use a 400 crank,pistons,rods with some machining so 350 block can accept it. Also, the deck may have to be machined unless you go with AFR aluminum high output heads which could gain you as much as another 100 horse and you might not be forced to have the deck machined on the original 350 block. Problem is that they are expensive
Best 383 Stroker Kit Reviews: Only 5 Out of 85 for February 2020! Depends how far you want to go with it. There are other concerns with clearances on the piston rod caps. I think they have to be ground for clearance. I think the kit takes this all into account instead of paying a machine shop to machine,balance. Depends on condition of cylinders. Are they at standard bore? Are they out of round? I think they take it 30 over for the 383. Not sure. So if you were to do all of the above you definitely should have the block checked out before putting a dime into it. Pretty sure a light build 383 stroker engine puts out approx. 400-450 horsepower but they go higher depending again what you want to spend. I would say you could spend on the low end maybe $2500-$3000 depending on how much you are capable of doing or are willing to do. The high end could easily reach $7000 upward. If you plan on going above 500 horse, the block should be a 4 bolt main. I think a two bolt main is good to around 500 horse. The block you have might be able to be machined to a 4 bolt. Not sure, but I think so. Just more money. Also, be careful what drive you attach all that power to. I believe the Alpha Ones are only good for up to about 300 horse. Maybe a little more for some high performance Alpha's . Not sure of that either. It really depends on how much you are able to or are willing to do on the build along with issues concerning cost. I would try and keep the compression ratios on the lower end. High compression engines and a marine environment could get expensive really quick! lol You want max torque at low rpms, the right type cam,pistons,rods,etc. so the engine will last not self destruct. You need something reliable. I would love to build a 383 but have not been able to come up with the money,time,block. good luck.