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Discussion Starter · #1 ·
Ok I have a 289 w/ flat top pistions and stock 54cc 66 heads w/ roughly 10:1.
I've been looking at some differenet aftermarket heads w/ a 58cc chambers. Just curious if i did the swap is it a simiple matter of getting a thicker gasket to maintain near same 10:1 compression? How much roughly would i loss in compression going from 54cc to 58cc head? Any thoughts or advice is most appreicated...
 

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Discussion Starter · #3 ·
Yes, i meant thinner gasket. Would compression still be close to 10:1?
You may have to be patient as I'm still a novice when it comes to motors. I don't plan on touching the buttom end. When you say zero deck are you referring to the block surface itself?
 

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Zero deck means milling the block to bring the piston level with the deck, but since thats not an option, use a thinner head gasket, what gasket are you using now?
 

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For every .010 you shave off the head gasket, you will loose about 2cc. I don't know how thick your current head gaskets are, or how thin you can buy, but if you go from a stock .040 gasket to a .020 gasket, you'll get the 4ccs back, although your quench distance (distance from the piston to the head) could be dangerously close. I'd check how far the pistons are down in the hole (below deck height) at TDC, then get the thinnest head gasket that you can get that will still maintain at least .040 distance between the piston and the head.
 

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However, assuming you kept stock .040 gaskets, and your current compression is actually 10:1, you would only drop to 9.3:1 CR, which isn't too bad... that's what my 289 has.
 

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You could have the new heads milled prior to installation for no loss of compression. It wouldn't take much to go from 58cc down to 54-55.

_________________
'58 Morris Minor 289 S/S MM
'62 Falcon 351W "Just Falcon Around"

<font size=-1>[ This Message was edited by: Just Jim on 7/21/06 5:17am ]</font>
 

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Discussion Starter · #8 ·
I know it was a fel-pro 8548-pt-1 as i still have an extra one as we bought a few of them.
 

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I think that gasket is 50 compressed, I cant remember off hand, research it and if so, just drop to a 38 or 41
 

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On 2006-07-20 14:15, Motorhead wrote:
For every .010 you shave off the head gasket, you will loose about 2cc. I don't know how thick your current head gaskets are, or how thin you can buy, but if you go from a stock .040 gasket to a .020 gasket, you'll get the 4ccs back, although your quench distance (distance from the piston to the head) could be dangerously close. I'd check how far the pistons are down in the hole (below deck height) at TDC, then get the thinnest head gasket that you can get that will still maintain at least .040 distance between the piston and the head.
Hmmm. My pistons stick out of the hole .011 and the head gasket squeeses to .039 and have run it plus 7000 rpm's a bunch of times in the last 3 years. Its still running strong. Going back to the track in a couple of week.
 
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