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#1
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1971 #96 head rebuild ??
So when you have hardened valve seats installed,do they just do the exhaust or both???
I'm going a have my #96 heads done when i get to Cape Coral soon for my 462 that has #62s now.. I am sure the 62's need to have the same done since i did them back in 1995..not many miles since i only drove the car in the summer,
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1977 Trans Am,400 4 speed,numbers matching car 1979 Bonneville ,1 owner car... 1997 Trans Am convertible,LT1/auto. |
#2
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Always have done just the exhaust valves on the ones I have had done. Never had the machine shop even ask if the intake valves should have hardened seats. I think it is the heat and gasses and lack of lead that come through the exhaust valve that calls for the hardened seats.
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#3
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You should confirm but IIRC, '71 engines had hardened seats.
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"At no time did we exceed 175 mph.” Dan Gurney's truthful response to his and Brock Yate's winning of the first ever Cannonball Baker Sea-to-Shining Sea... Still have my 1st Firebird 7th Firebird 57 Starchief |
#4
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I can’t remember either as I think it was around ‘71 they started. Regardless,the stock 96’s on my ‘71 had many sunk exhaust valves when I tore my engine down. So I had hardened seats put in when I had the heads redone.
On the other hand, I just had the heads redone on my ‘62 Mercury. I opted NOT to go with hardened seats as the car is only driven 500 miles a year. I figured my money could be spent elsewhere being on a tighter budget these days. I’ve never heard of putting hardened seats on the intake side.
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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. Last edited by 67drake; 01-10-2021 at 08:00 PM. |
#5
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Later seats went through a hardening process to the cast iron. I've seen rescission in high mileage later heads that were ready for actual hardened seat inserts. Only time we did an intake valve seat is when something went wrong and seat was damaged, and then only on that damaged seat.
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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 in progress. |
#6
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I have put new seats on the intake side to restore sunken seats on one pair of heads. It was from a piss-poor valve job, not wear. The valves on two cylinders were sunk so bad they were below the roof of the chamber. The others were varying heights and not that great. Normally you only need them on the exhaust side, but if the car doesn't see sustained high RPMs or that many miles, I wouldn't bother if the current seats are in good shape. Just cruising around town and the occasional short trip on the freeway shouldn't wear out your exhaust seats, even with unleaded gas. If you have high 3- to 4- series gearing and drive at higher RPMs a lot then the hardened seats make sense.
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
#7
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The Pontiacs usage of a 30 degree Intake seat since day one in 1955 on 99% of the heads wares far less even when the valves and guides are pretty darn loose!
A 30 degree seat clamps to make a seal far more then the wedging action that a 45 degree seat does, especially when a 45 degree set up gets warn and the valve swims around. This is also the reason a 30 degree seat with a valve like the 2.11" used needs 10 to 12 pounds more seat pressure then a 45 degree seat with the same size valve because a 30 degree seat set up will tend to suffer sealing issues at high rev's more due to valve bounce .
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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! |
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