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#1
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1971 #96 heads info
Hi: Just looking for confirmation on info of #96 factory heads.
What size screw in rocker stud? Factory CC size? Going on a 455, so CR? Factory valve sizes? Thanks for any help Charles |
#2
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Chuck
I had a set on a 455 years ago: 7/16" studs 96cc's About 9:1 CR 2.11/1.77 Jeff
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Carburetor building & modification services Servicing the Pontiac community over 25 years |
#3
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Thank you Jeff..
Charles |
#4
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Well, listed as 96cc's but the four virgin pair I have come across were right at 101cc's. They were still a little over 96 after a mild cleanup cut.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#5
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Yup. My 96’s cc’ed around the 100-102 range. I had a few sunk valves too
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71' GTO -original 400/4-speed/3.23 posi 13.95 @ 102.1 on street tires @ 4055lbs. ‘63 LeMans- ‘69 400 w/ original transaxle. 2.69 gears. |
#6
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As posted in 4 and 5 you had better CC them, as they are never as low as 96 CCs in chamber volume , and one you get that number if your then getting a valve job done on them then that will add another 1.5 to 2 CCs to the chamber volume .
if you use new valves you might only add 1 CC to the chamber volume if it does not take much meat off to get the seats in fresh shape again. Most of these heads that I have had on my flow bench produce Intake flow numbers of 200 cfm@.500" @ 28" and out the Exh side 165 cfm@.600" @28". With a 80% Exh to Intake ratio if you run a single pattern Cam of .525" to .550" lift and have a 9 to1 comp ratio you will have 390 hp in control of your gas peddle ! Another thing to know about all Pontiac iron head is that the factory sets up the Intake valve seat OD some .050" to .070" smaller then the OD of the valve used. This means that a valve job done with the right angles to bring the OD of the Intake seat out to within .010" of the valve OD with pick up a nice chunk of air flow up to .300" lift. Keep this in mind!
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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! Last edited by steve25; 01-20-2020 at 07:41 AM. |
#7
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Quote:
GM claimed that all '71 and up heads had hardened exhaust seats. Obviously my heads did not come that way. So, if you intend to do any serious amount of street miles, hardened exhaust seats would be a good idea. |
#8
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I got down to 12.07 with unported 96s on my 455. I thought the hardened seat heads were the X heads with Olds looking exhaust. ?
My brother is sitting on a complete std bore 71 GTO engine someone gave him when they put a Chevy in the car. Thanks ! |
The Following User Says Thank You to Dragncar For This Useful Post: | ||
#9
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I don't man!
I ran 96s on my street Blower motor for 15 years and some 25k miles with the spring pressure needed for a solid roller and never had a Exh valve ression with .070" wide Exh seats and factory RA4 valves, not even stainless steel! To this day I don't like the finish a cutter leaves for a seat when compared to a fine cut stone with a tight set up!
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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! |
#10
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Quote:
Headers or exhaust manifolds? |
#11
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I ran these heads with the dreaded xe284. Engine dyno 450h/ 532 t. Dipped into the 11's once, 11.98 @ 3700lbs. Ran 12 oh's all day long.
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#12
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450 flywheel hp should take a 3700 lb car to under 11.50 times if it's all getting hooked up.
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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! |
#13
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Were your heads ported?
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#14
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We've had to go with hardened seats with some 96's and also 6X heads. Couldn't tell you whether some weren't originally hardened properly or maybe other abuse over the years prompted seat erosion? Last set of 6X's did have some water damage and it seemed to attack the exhaust seat area more than other parts of the chamber.
__________________
Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#15
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Quote:
Originally had 4.10 gear and 13% slippage. It's tongue was hanging out at the stripe. I believe it had an 80 in with the Jim Hand Converter. Never went to the track with that. |
#16
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They were cleaned up maybe 10-15 cfm. At lift they were 213 - ish. Yanoski went through them. |
The Following User Says Thank You to ponjohn For This Useful Post: | ||
#17
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Quote:
The GTO had cheap headers and the Firebird had its stock log-style manifolds. The GTO had 3.08 gears with T-400 and the bird had 2.56's with a T-400. |
The Following User Says Thank You to hgerhardt For This Useful Post: | ||
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