engine BORING question /hypothetical scenario

[choprods]

Was wondering- lets say it was a 400 small block chevy motor block we are talking about.
I am aware of the potential heating tendencys of a stock 400 but I wondered about Bore size/wall thicknesses.
In a case where it was to be a strictly RACE motor...I mean no cooling system-HARD BLOCKED/FILLED BLOCK....tow it to the line [every time] deal.....
what is the stock thickness of the bores now and what would they stand in an OVERBORE to still maintain the strength needed to withstand the compression/combustion pressures present in such a motor with say only 10-1compression? I realize you should not take a good stock bore block and use it but say a block that is already .060 O/S now?
and to add more what about the same condition 327 block that is already 60 over.......... What is the formula/limitations reguarding minimum thickness on the bores[400]/or sleeves[327]?

[AHotRod]

.060 is not uncommon on 400 CID Chev, as we sell ( Speed Pro - TRW) as fair amount of that oversize. If you fill the block with "Hard-Block" which stabilizes the cylinder walls and increases ring seal, you should be able to throw pretty much anything you want at it with in reason as to the crank and rods.
Glenn Hayes

[Scotch]

Good shops have an electrical tool to measure wall thickness. Core shift means it's different for every block, and the 400 could be good, or maybe not. Call around to see if you can find a shop with the capability to measure wall thickness electronically, and pay the minimal fee to have yours "Sonic checked". It's worth it, and you'll know exactly how far you can go.

Scotch!~

[LUKESTER]

Do NOT use a honing plate on 400 blocks as they will most certainly crack after you assemble and run them. LUKESTER

[Hot Rod To Hell]

[ QUOTE ]
Do NOT use a honing plate on 400 blocks as they will most certainly crack after you assemble and run them. LUKESTER

[/ QUOTE ]

Well I have a 400 that has been re-ringed TWICE and still has 60% leakdown, becuase it was NOT honed with deck plates.

Any suggestions?

[fab32]

Lukester, I don't know where you are getting your information but using a block plate while honing a 400 is an accepted practice. How else would you get a round bore with the heads bolted on. with the 400 having some "issues" to start with it only makes sense to use every procedure possible to insure an "in use" round bore to keep ring seal at a maximum. I can't believe some of the "wives tales" that have persisted throughout the history of the 400 as the skeptisizm started right from the begining. Now the 400 is every much a kick ass motor as the other big and small block offerings in the Chevrolet lineup. Make sure the steam holes are CLEAN, drill the appropiate holes in the heads if they aren't already present, use 400 head gaskets, do all of the other normal block and component preperation, assemble it clean, RUN THE PISS OUT OF IT.

Frank

[fab32]

BTW, I always take a conservative approach when boring a 400. Keep as much of the cylinder wall thickness as possible. This is not an engine to gain a couple of cubic inches with a boring bar if it isn't necessary. .020-.030 is what I like and have only gone .040-.060 at the customers insistance.


Frank

[Hot Rod To Hell]

Well hey Frank... I know a guy that has a pretty good line on a 400 Bowtie Sportsman block http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif... any ideas what they'll take for an overbore? Or does it still come down to sonic testing?