76 cc head question

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Anybody know roughly how many CC's would be removed from a 76 CC chamber by whacking the head .025thou     :listen:   Gonna check um when they're done, but just wondering if anyone knew.........
 
Shawn,I figured that up mathematically one time and it comes out to about 4cc if I am right.Let me know what you get.
  Terry
 
POTTER said:
Think about un-shrouding too. You'll gain that plus 4 or more back.
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R U talking about when you mill the head youll gain back what youve unshrouded because of the bigger(volume)area in the chamber Rich?
 
You'll gain some of it. It's real easy to get as much as 84 or more cc's on a real unshroud. When you take everything above the 45 degree seat and continue the line onward, only hampered by gasket sealing ring. 45 degrees works best on a 45 degree seat and so on. If you relieve below that line , it creates dead air space....above it, well , the chamber is in the way. You can also eye brow beyond that with a copper gasket. From a physics type point of view, you only want to unshroud the exhaust side , to keep the entry good and straight (not causing dead air space behind the sealing ring in the cylinder wall and on a high rpm, fast air head like a small block....turning 9000, this maybe true. I think unshrouding  the intake side still helps on a lower rpm (6500 or less) Cadillac. These will yeild great cc losses in a head.
 
Im at 83cc's, but want to gain some of the compression back, so im having the heads cut .030-.040 to stay safe on the head thickness, want to take about 7-8 cc's back out of the chamber, for about 13.38 to 1 compression
 
13.38:1 compression ratio. "Crisper than a fresh head of lettuce".
 
You can safely mill .050". There's something about 13.8-1 that has a ring to it.  :D. You can feel the difference too!
 
If that car doesn't run tens n/a I'll drive to your place and eat the whole damn thing . Wish I could be there to hear it fire up the first time. :D :jack::D

    Terry
 
:D  Maybe i'll push the limit then and go .050 

  Hey Terry < :screwy: :D   :thumbup:
 
cadillac512 said:
If that car doesn't run tens n/a I'll drive to your place and eat the whole damn thing . Wish I could be there to hear it fire up the first time. :D :jack::D

    Terry
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If it doesn't run tens, I wanna be there to see Terry eat it. :D
 
No sandbaggin' either....and no payoffs either, you guys. :mischievous:
&nbsp; Terry
 
POTTER said:
You can safely mill .050". There's something about 13.8-1 that has a ring to it. :D. You can feel the difference too!
Click to expand...


Got my heads back today, had .045 taken off of them. Started at 83cc's after the chamber was done. I just cc'ed them and in my case it was worth 9cc's. The static compression ratio will be 13.53 to 1, I'de say you were pretty close in your guess Potter.   ;)   lol
 
Shawn,

So, .005" per cc. I assume that a 120cc head would take 7 0r 7.5 thou per cc, since the footprint is bigger.

Damn. 13.5-1 is a bunch. I bet that sucker will really cackle. How much cam you gonna run?
Dave


Got my heads back today, had .045 taken off of them. Started at 83cc's after the chamber was done. I just cc'ed them and in my case it was worth 9cc's. The static compression ratio will be 13.53 to 1, I'de say you were pretty close in your guess Potter.   ;)   lol
 
Its gonna be a 246 @.050 solid grind with .612 lift w/ 1.7 ratio rockers.......Hoping to have an Alky carb done before the season is over too 
 
Shawn,

Pretty short cam for 13.5-1. That sumbitch will really hit the convertor. Alky = pia, but it does work well at high CRs. Fwiw - I know a fellow that's running an alky fueled 400 sbc at 16-1 CR with a 260 something at 50 roller. It pumps at over 300 psi!
Dave


kwikcad500 said:
Its gonna be a 246 @.050 solid grind with .612 lift w/ 1.7 ratio rockers.......Hoping to have an Alky carb done before the season is over too 
Click to expand...
 
Dave i had a feeling you would say that, lol&nbsp; Shooting for 210+ on the cylinder pressure
 
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