Hey guys. I have aquired a new 350 block. I was wondering if I can stroke it to a 383 since it is only a 2 bolt main. I don't want to blow the crank out the bottom of the oil pan. Also, what is the horsepower limit on a 2 bolt main engine? Thanks for all the continued support.
As far as hp i have seen a 450 hp 350 with 2 bolt mains. I've got a 4 bolt main 350 that i'm thinking about building for the time being till i can find a 454 block. I'm going to run 3 2barrel carbs on the 350 and have about 9:1 to 9.5:1 piston compression. I figure about 300- 450 hp with all the stuff going in to it. cowboy 1961 chevy 1/2 ton shortstep known as sarah
2-Bolt mains should be good for around 400 horsepower. I wouldn't try anything above that. I've never seen a hot rod rip the mains out of its engine block, and neither has my good buddy, machinist Ernie Cross. I asked him about it when I bought my block(a two-bolt). He said that in higher horsepower applications, the two-bolt mains can walk and squirm a little bit at high RPMs causing bearing failure. I've gotta take his word for it, he's a smart guy. As for the actual fit of the crank in the block, the oil pan mating faces parallel to the crank have to be notched so that the rod bolts on the longer stroke 400 crank won't whack them. Some more clearancing might have to be done on the bottom of the bores and on the area above the main caps(sort of between the main caps and the cam tunnel). I hope this gives you some idea of what to expect, but you should talk to a machine shop since I've never actually built a stroker motor before. Oh yeah, Is your block one with the one piece rear main seal? If it is, you'll have to buy an adapter to fit the 400 crank into the block since(I think)all 400 c.i. engines used the two piece seal. The shape of the crank is different at the back. Good Luck, TrustyRusty
You can buy a 4-bolt conversion kit and it will actually end up stronger than a stock 4-bolt. This is because the 2 outer bolts are drilled in at an angle providing a stronger hold. A machine shop has to do the conversion. I had a 2-bolt 350 in my el camino pushing a little over 400 HP, It blew up on me last year. A wrist pin broke and shot the rod through the bottom end of the block. I wouldn't worry about a 2-bolt block if you are going to be at 450 HP or under. Good luck! '66 C10 Fleetside LWB 350/350
