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#1
06-03-2012, 06:57 PM
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Anybody know cc,s on casting 13,s
Just wondering , from factory what were these heads cc,ed at??? 1970 casting 13,s
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#2
06-03-2012, 07:07 PM
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This source ... http://ronspontiacpage.com/reference...headspecs.html ... says 72cc
__________________
Peace, through close combat. |
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#3
06-03-2012, 07:47 PM
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Actually,virgin un-cut #13 heads will be more like 76 to 80 cc's or so as SOP.
That 72 cc's is just the "nominal" cc spec,actual cc's are typically more than nominal. FWIW Bret P. |
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#4
06-03-2012, 09:25 PM
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I recently cc'd a pair at over 80 cc's-82 if I remember correctly.
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#5
06-04-2012, 04:33 AM
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Yeah,dont doubt it.
I should've added "possibly more" to my cc numbers just to cover my @ss. That or said "at least" before them... LOL Bret P. |
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#6
06-04-2012, 06:02 AM
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The`ll go over 80 if they do not have the stock flat face valves and or have had a valve job applyed.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#7
06-04-2012, 09:02 AM
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If they are really that big, maybe with tuliped valves and a thick gasket, could be good for 455? Somewhere between 10 and 10.5? Thoughts?
__________________
1978 Black & Gold T/A [complete 70 Ram Air III (carb to pan) PQ and 12 bolt], fully loaded, deluxe, WS6, T-Top car - 1972 Formula 455HO Ram Air numbers matching Julep Green - 1971 T/A 455, 320 CFM Eheads, RP cam, Doug's headers, Fuel injection, TKX 5 Spd. 12 Bolt 3.73, 4 wheel disc. All A/C cars |
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#8
06-04-2012, 09:10 AM
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And #12?
#16?(big valve) #62? Most books says 72cc but I have heard other/different figures for the last 15 years.. So what`s the TRUTH? |
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#9
06-04-2012, 09:37 AM
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"YOU CAN'T HANDLE THE TRUTH"
I think the truth is that you are better off checking all of them yourself because the nominal volumes listed by many sources can be off a significant amount, usually enough to make a noticable change in compression ratio. By the way, my set of 1970 13's were at 76 - 78 cc's.
__________________
70 Goat 74 Ventura 63 Cat 56 GMC et al. |
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#10
06-04-2012, 10:12 AM
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Pontiac factory specīs:
#12 are 66.27cc. #13 are 75.70cc. #64 are 89.96cc #614 are 69.12cc. |
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#11
06-04-2012, 10:42 AM
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Agree 100%. Normal variation, 40 years of Lord knows what, and today's lousy gas make guessing dangerous.
As the great Mr. Kissinger once said: "Trust...but verify." Quote:
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#12
06-04-2012, 11:42 AM
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In the mid to late 90's I cc'ed the chambers of several pair of virgin 13's at 78-80cc. Vakves set high & I knew what a pair of factory head gaskets looked like. It surprised me as the old HO book showed 75cc chambers & I knew Pontiiac heads featured a fully machined chamber. Ran it by my Pontiac engine builder, told me at the time, he had max ported a pair of 13's in the early 80's for his early Bird racecar (434). He too didn't realize the 13's were upper 70's cc range or he would have started with '68 model 16's or 67 model 061's.
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