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Discussion Starter #1
I am building (on a tight budget), a 327 cast #3914660
Out of a 1968 3/4 ton pick up.
I have two different set of heads i can use. The first is the 327 heads cast # 3998993 , or a set of of a 72 350cid. Cast #,
3998993. Which set will be the better ones, with regards to hp.,I am installing a mild cam, performer intake and 1407 edlebrock carb. I just dont know much about it.
 

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welcome Dean
on those 993's, the combustion chamber cc maybe a bit big at 74-76cc for a 327,,
unless your using a higher dome piston, and/or decked block, thin gasket..
may or maynot have hardened exhaust seats, started around 73-74' with un-leaded fuel..
there more of a stock 350/400 head.. could be a heavy casting tho, got pics??
stockish 327 usually has a 64cc chamber head..
.
both sets may be the same, but they could have bigger valves,
or bigger/smaller chambers than the other.. they may have been milled too..
you'll just have to do some measuring/calculator-ing..
.
Compression Calculator
 

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Discussion Starter #3
welcome Dean
on those 993's, the combustion chamber cc maybe a bit big at 74-76cc for a 327,,
unless your using a higher dome piston, and/or decked block, thin gasket..
may or maynot have hardened exhaust seats, started around 73-74' with un-leaded fuel..
there more of a stock 350/400 head.. could be a heavy casting tho, got pics??
stockish 327 usually has a 64cc chamber head..
.
both sets may be the same, but they could have bigger valves,
or bigger/smaller chambers than the other.. they may have been milled too..
you'll just have to do some measuring/calculator-ing..
.
Compression Calculator
THANKS, I NEED TO DO SOME HOMEWORK, THE 72 350 HEADS I KNOW ARE 76CC ,AND THE 327 HEADS ARE 70CC. THE INTAKE AND EXHAUST VALVES ARE THE SAME. OTHER THAN THAT, I HAVE TO GET SOME MEASUREMENTS. IM RUNNING THE STOCK PISTONS, AND THE BLOCK HAS NOT BEEN BORED OR SHAVED.
 

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Be careful with the compression ratio which is directly tied to the combustion chamber in the heads. With too much compression, you won't be able to run pump and you definitely don't want to experience detonation and pinging. If you are set on building a 327, do a LOT of research online and find articles on building 327s. From these articles, you'll get clues on what heads to run. Good luck!
 

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On a street motor, I experience more performance and a general, overall, enjoyment with lower compression.. The gains you get from compression 10:1 and up aren't worth the troubles. Another thing I never hear about is how badly high compression motors run in very hot weather, it's like they have gravel in the combustion chambers. Now I am talking street motors not track. All though I have seen some low compression motors turn some crazy fast times in my day...
 
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