Well I thought I was doing pretty good with my 377 build untill I checked to see if my pistons fit the bores. The block I got was already .030 and was suppost to only have "30-40 laps tops" when a main spun. It was in a circle track car. My pistons rock pretty good inside the bore telling me it`s got alot of clearance. I haven`t actually measured it yet but I`m positive it`s too much clearance.

The guy was running JE pistons so I figured my Ross pistons would fit pretty good since it was a "fresh" bore. I guess that will teach me to get my block checked before buying pistons in the futur. I got a good deal on the pistons so I bought them before checking the bore.

I had that happen myself. My 509 had 50 runs on it so I thought I would just buy the new pistons for the same bore. The machinist suggested that he check it first. He said the piston to wall was a little loose so rather than run a loose motor we bored .030 and got the new pistons. I thought a quick hone and it would be done.

There is a old school method of knurling the pistons to take up some of clearance, but I really wouldn't recommend it, only as a last ditch resort if you had to something right now.

Hey before we make any more suggestions, you really gotta measure it up. Putting the pistons in and saying they feel loose is not a good way to judge. Get the bore gauge and mic out and let us know.

Hey before we make any more suggestions, you really gotta measure it up. Putting the pistons in and saying they feel loose is not a good way to judge. Get the bore gauge and mic out and let us know.

I do plan to measure it but I`ve built enough motors to know how the pistons should fit. It rocks way too much. I`ve got basically a complete longblock and was hopeing to get the block down to the machine shop and have it honed and decked but I`m not in any hurry to get it together so I`m going to look for a standard block and have it bored to the correct size.

i feel your pain. the 400 "standard bore block " i was to pick up was a standard .040 over. so long to that, back to looking for the right block. Like you, i'm in no hurry. good luck if i find a stash I'll give a yell in your direction.

Thanks. my buddy has one but he wants $350 for the bare block and that seems a little high to me. I`m going to check with the machine shop I use to work for on Monday. I might be able to trade my block and some cash for a good standard one.