Thread: What is the STD bore on a 502?

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Depending on where I look, I see the standard bore on a GM 502 is either 4.466 or 4.47

I am trying to make mine a stroker, but don't really care to bore the cylinders +.004 (if I am going to bore it would be right up to 4.5). But I am on a budget and would like to keep the block away from the machinist for the time being. It's a brand new block, otherwise it wouldn't be a question.

To make it a stroker, I already have the 4.25 crank, and 6.385 rods. But I need new pistons with the correct compression height. I can't find any maker of 4.466 pistons for the longer rod, but many make 4.47.

I would like to get this build underway and don't want to be set-back by anything once I start wrenching. Please let me know if any of you have stroked your 502 without boring, and who makes the pistons? Keith Black is probably where I am leaning for my budget build - they make the 4.47.

Thanks for your help

I believe the standard bore is 4.47 on the ZZ502/502 ..............

Kitz

Thanks for the input, I hope it is 4.47 too.

KB says STD bore is 4.466, but the first piston size they make for a stroker is 4.47.

I am taking the digital calipers home tonight... I will find out once and for all.... maybe the question should be "if cylinder bore = x; piston diameter should be x-y; what is y?"

I think they're just rounding off. But if you're replacing pistons, you really should have your machinist finish hone the bores to the piston size. Unless you happen to get it 'just right' from the box. Measure and see what you get. John

So you think I should just go with the 4.47" stroker pistons, (as they are the smallest available for this block) and if they don't fit have the machinist handy?

Don't have much choice with this one anyway. So what should piston to bore clearance be on a cold engine?