[Mike68RS]

I took my 350 apart yesterday and measured the cylinders. I measured at the top, middle and bottom and the largest number i got was 4.004. Can I install standand hyper. pistons or does it need to be bored? Can someone give me the specs at which a 350 needs boring?

Thanks for the help!
Mike

[pdq67]

Maybe BillK will pop in here and offer his opinion... pdq67

[JohnZ]

Standard bore specs for a 350 are 3.9995" - 4.0025"; have you checked each hole for taper?

------------------
JohnZ
CRG
'69 Z28 Fathom Green

[stingr69]

Well, it is realy a judgement call. If you want a number for reference, a general rule is .006" wear should be good for 50,000 miles or so with a good set of moly rings according to Vizard. Your .004" wear should last a bit longer with a careful re-ring job. A re-bore would be better, but much more expensive especialy considering the cost of the required new pistons. Check the old pistons wear patterns. You are looking for inconsistent wear patterns especialy on the skirts. If you see issues there, it is time for more $$$, parts, machine work, etc.

-Mark.

[Mike68RS]

I decided after some research, that it would be best to bore the block. Hyper. pistons do not expand much at all. Speed pro's website give the minimun clearance at .001 which is really tight, but again their minimum. My machinist said he will install them at about .002. I also do have some tapering within each bore. I'm going .030 over, new Scat crank, Trick flow heads, new Crane 278 energizer cam, ect.

Thanks!
Mike

[pdq67]

My new Northern Automotive cat. that came yesterday in the mail lists some inexpensive forged flat-tops.
I think $32 each or something reasonable to me.. Speed-Pro's? Sorry, I don't have it in front of me right now and don't want to snoop around where the wife is at...

Too early, kinda like waking a junkyard-dog!! He, He!!! pdq67