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#1
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#12 heads with stamped "2"
have seen a number of stamped 2s in my day but have never heard that they were only installed in early GTOs.
http://www.ebay.com/itm/70-PONTIAC-G...b4dfa2&vxp=mtr from the auction for those who can't link... " These rebuilt #12 10.5 to 1 compression heads are from a 1970 GTO and both have an early manufacture date of November (K) 21 1969. Being an early casting, the #12 has the 2 stamped as a production transition only found on low serial number 1970 GTOs not 1970 1/2 Trans Ams, which I bought them for. The heads were machined and pressure checked by a reputable shop (receipt included). All new intake valves were installed. Stock 3/8" Bottleneck rocker studs included. Ready to bolt on. The heads weigh about 65 lbs each so shipping will run $185 unless they are picked up." First, I don't consider K and early casting. Secondly, since all engines originated from pontiac, I don't see how engines with a full 12 casting were isolated and installed in trans ams. Sounds like good story though. The guy is probably not comfortable with the stamped 2 and doesn't realize the heads are probably legitimate #12 heads. Can't say I blame him though. |
#2
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sure they arent 13s?
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Mark.. The Goat whisperer "I spent a lot of my money on booze, crazy women, and fast cars. The rest I just squandered." |
#3
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would have to CC them to find out since i thinks 12s have the smallest chamber...difficult to fake a chamber size.
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#4
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12's weren't being used in F-bodies until very late January or February of 70.
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Some guys they just give up living And start dying little by little, piece by piece, Some guys come home from work and wash up, And go racin' in the street. Bruce Springsteen - Racing In The Street - 1978 |
#5
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Good point. that being the case, the seller's issues in the casting date since K may be considered too early for a late Jan car.
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#6
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ive seen 1 and 2 stamped but not just the 2..you can make and smaller CC ..mill them
im no expert
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Mark.. The Goat whisperer "I spent a lot of my money on booze, crazy women, and fast cars. The rest I just squandered." |
#7
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I thought the stamped heads were the service replacement ones.
__________________
Some guys they just give up living And start dying little by little, piece by piece, Some guys come home from work and wash up, And go racin' in the street. Bruce Springsteen - Racing In The Street - 1978 |
#8
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I have only see 3 or 4 of these stamped 12s. And if i recall, the casting date matched the other components on the engine.
But stamping the SR heads makes sense. |
#9
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I have a set of 12's dated F249 - the first casting batch.
Have seen at least 3 other posts in threads where guys have had the same F249 dated 12's. 12's and 13's were pretty high production. Not sure off top of my head anymore - if there any numbers under the valve cover area to ID them or not. |
#10
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I thought that I read some time ago that rebuilders would do this to have a "matched" pair of heads...??
I hace never heard of this actually being anything that PMD did; I mean since the '69 #48's were essentially the same as '70 #12's (and '69 #62 about the same as '70 #13's), why would PMD go through the added effort of casting a newer head, then grind off a part of the (or the whole) number, to stamp it differently; It just doesn't make sense to me. I'd see it more plausable that someone took creative excersise to make a cylinder head more desireable... I would also think the full part number would be a better gauge; as all but the RAIV had the part number visible with the valve cover removed.
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
#11
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12 heads
I have original 12 heads dated F249 on my 09E built Judge, no numbers under the valve cover, just the "casting clock", and the 12 is cast.
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Jason Last edited by Jason67; 02-27-2016 at 10:49 PM. |
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