Racingjunk Forums - Truck tall deck BBC GM block????

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It put 726 hp on the ground, at least that day it did.

Quote:

Originally Posted by dparker

Pulled the pan and the block is ground on extensively. The rod bolts on the outside of the rod are ground slightly to clear something, maybe the cam. I'm wanting to check the true displacement, can I do this by just pulling the pan. I believe the crank is at least a 4.375 and maybe a 4.5 stroke. What's the easiest way to check from here. Its also going to be a little hard to check bore size. Everything looks great, so I really don't want to tear the whole engine down if I don't have to. Its suppose to be new with just 7 passes and so far I can't see anything that would disprove that. I used a cheap set of plastic calipers and got 4.32 at the bottom of the piston skirt. The engine came out of a 2500lb chassised car that ran a 8.26. I haven't seen this combo before and I'm starting to wonder alittle about what kind of HP it will have.

I'm betting you have a 4.375 bore and 4.5 crank, if it's a true 540" motor. Take a piece of 1/8 welding/brazing rod and cut it to as close as you can to 4 3/8", then try and fit it into the bottom of the cylinder. If it's a 4.5 bore it will have plenty of room, if 4 3/8" it'll be tight. You can also measure the stroke from the bottom but it won't be as easy unless you have 1,2,3 blocks and a depth mike.

Zip.

If you need answers, positive answers, rip it apart and do all the measuring yourself or have a good machine shop do it, then you will KNOW what you have exactly and not blow it up on your expense!!!!!!!
You will win in the long run doing it this way, and a little more spent now, save a lot more later :wink:

My 2 cents worth.

Elkyman

you need to measure the diameter of bore,my understanding is you got 4.320" well that would be a 4.250 stock bore size that was bored open .070".if you find a way to measure piston travel up and down that will be your stroke naturally,but without poping head off or dropping pan,dont know how to check for stroke any other way