Is that pushing it? .171" flat cut?

Yep! Too much. That's not all that much less then 1/5 of an inch, and would probably weaken the head too much. Most limit it to .090" (just over half of .171"), although I've heard .100" (and slightly more) is possible. Sounds like you are trying to acheive a closed chamber...yes?
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LIVE SEXY CAMS

Are you looking for 11 or 12:1 compression? It may be OK, but that's probably pushing it. I have done 0.110" on manifold side and 0.210" on plug side successfully.

Lou

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Home of Slant6-powered fun machines since 1988

Nope I am looking for 10.5:1 with the pistons down in the hole .183"

Here is the deal. The head has already been cut It seems as the chambers are 54cc. I want to cut another .130 or so to get a 34cc chamber and 10.5:1 with a .18375 deck height.

Pistons -.18375 in the hole
.041 head gasket 3.51 diametier
3.46 bore
4.124 stroke
65 (with the 15 added) intake closing point.
My calculations say I need about a 34cc chamber.
What say ye?

Do yourself a favor and cut the block.

.120" on the head will get you 34 CC if you are at 54 now.

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Official Cookie and Mater Tormentor.

I've cut .100 off my daily driver

Kev

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You need to take some off the block..........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Cut the deck. I cut mine 0.120" This was for my particular build, so do the math for yours. You won't have to cut it as far as I chose to.
This leaves lots of meat in the head to try to keep the valves away from the bores. Still plenty of holding power for the head studs/bolts.

If you run oversize valves, you may have to relieve the bores to avoid interference. By not cutting the head, you keep them further away and minimize the possibility of putting a valve into the deck at the edge of a bore.

Check any head and block prior to assembly to make sure the combustion chamber is alligned over the bores. Bolt it to the block while the Reciprocating assembly is out, and turn it over to see. Adjust as necessary with offset dowels.

I had an engine bend some shiny new valves due to missalignment.

CJ

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Part of Tyrde-Browne Racing

I cut.170 off the head and .135 off the block i o.ring the block and run a copper head gasket

Edd PM sent.

At 54cc's it may not have been cut. I would just cut 0.120" off the head and have about 10:1 comp. No reason to shoot for a higher number and risk the head on a street car. 10:1 will be a big bump up and you will like it. Then, when you want to pull the shortblock apart, you can cut the block to get whatever comp you like.

Lou

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Home of Slant6-powered fun machines since 1988