Thread: 396/402 question

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Hi, this is my 1st post and I'm sure this question has been beaten into the ground, but I have to ask. I recently picked up a chevy big block, 3969854 casting number, and a set of heads 3999241. I quickly ran a caliper, did not have a mike with me, and got 4.114 on the top of the cylinders, so I'm guessing its the 396 with wear??? Ok dont roll yer eyes , I'm new to this remember. Anyway wanna build up a small light ride for my local strip, and utilize weight to hp ratio to the max. Im thinking opel gt. Question is: will the heads I have hold up to a 450-475hp build without alot of carressing or is there a better pair to start with? Production type. AND.. can someone tell me what parts off the 427 and 454 will interchange to my favor. Ive heard people on here talking about strokin the 402. How is this accomplished??? Thanks guys for readin me.

Well, the block casting numbers say 1969 396, 2 or 4 bolt. Im really only familiar with the 454 blocks, but Im sure others here will help you out. The heads are oval port, semi-open chambers, should be about 113cc. They are not a popular GM head for sure, but I dont see where they wouldnt be a good head to use with a little work. The listing I have doesnt show the valve size, but I'll bet it's 2.06 intake and 1.72 exhaust. You can have larger valves installed, maybe a little port work, short side radius and bowl blending. That should do it. I dont know about stroking a 402...in my opinion, you would be better off starting with a larger block, maybe 454...but if you want to use what you just bought, Im sure it could be done, but I dont know if you would get the performance out of it, based on how much you would have to put into it...starting bigger would be much cheaper in the long run. Lets see what others have to say. And welcome!! John

Originally Posted by 1JohnnyO

Well, the block casting numbers say 1969 396, 2 or 4 bolt. Im really only familiar with the 454 blocks, but Im sure others here will help you out. The heads are oval port, semi-open chambers, should be about 113cc. They are not a popular GM head for sure, but I dont see where they wouldnt be a good head to use with a little work. The listing I have doesnt show the valve size, but I'll bet it's 2.06 intake and 1.72 exhaust. You can have larger valves installed, maybe a little port work, short side radius and bowl blending. That should do it. I dont know about stroking a 402...in my opinion, you would be better off starting with a larger block, maybe 454...but if you want to use what you just bought, Im sure it could be done, but I dont know if you would get the performance out of it, based on how much you would have to put into it...starting bigger would be much cheaper in the long run. Lets see what others have to say. And welcome!! John

I.M.O.,start with a 454 block and use a 4.25 crank.
You have 100 more cubes and it will fit any place the 396/402 will.

put a 454 crank in it and custom pistons will get you around 427 you can cut some pistons down on the deck. BUT to do this it would be cheaper to build it as a 396/402 they can run or build a 496. to make a 396/402 stroker it would cost more than to build a 496 less you have a 454 crank damper and fly wheel and a full machine shop