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#1
03-25-2024, 10:15 AM
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dilemma
Years ago, purchased a set of 5.12 stainless valves by mistake. I'd like to install them in a set of 6x-4 heads I ported and enlarged the exhaust seats. I figured using. +.050 keepers and ,080 shims I could get close to .020 of the 1.6 installed height of the springs I want to use. Has anyone done that, or should I just buy longer springs or shorter valves?
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
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#2
03-25-2024, 10:26 AM
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With the difference in those valve lengths and a stock 6X valve installed height of 1.586” your going to have to make up about .160” which even with .050” difference in retainers is too much to make up and have things right.
If it where me I would get the needed correct springs such that you will not need .030” worth of shims. It will be worth it especially if your currency springs are not the crappy type with just a outer coil and a flat wire inner damper. Also if your new valves only have one groove for the keepers you will have to cut down the top of each valve guide for a positive type seal. And you will now your push rod geometry will need to get checked.
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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; 03-25-2024 at 11:23 AM. |
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#3
03-25-2024, 10:35 AM
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I have extra set of stock length 6X stainless intake valves, then you could keep all the stock geometry on the valve terrain. I would trade you if you wanted. I once thought I was ordering 2 valves, and accidentally bought 2 sets of 8. Lol…was a big order and got overlooked.
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#4
03-25-2024, 12:31 PM
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Win-win right there.
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 1970 GTO (Granada Gold) - 400 / TH400 |
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#5
03-25-2024, 02:55 PM
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Wrong!
It’s not a win win if he is going to run even just his RA4 , no less the RA4 with his high lift rockers because the stock 6X 1.586 to 1,590” installed height will not accept that .520” lift, no less running .570” lift with the 1.65 rockers. If that’s his intention of course.
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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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#6
03-27-2024, 12:55 PM
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OK what springs do I get for a RA 4 type cam with those long valves?
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
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#7
03-27-2024, 03:30 PM
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Track73 here’s what you need to know along with pictures.
I used a stock 6X head and a 2.11” x 5.100” valve and the head has a stock valve job. It has also had the guide cut to accept a positive .530” seal. The installed height is 1.720”. With a stock Pontiac retainer there is enough retainer to seal clearance to run .480” lift. So with a stock retainer you can not run 1.65 rockers. With a aftermarket comp cams retainer there is a clearance that would allow .580”, so then you can run the 1.65 rockers for a lift of some .515”. With the 5.100” length valves I would run a Crower 68405 spring. You will likely have to shim them .030” to end up with about 125 on the seat, but that and the other numbers I posted will swing around if the heads have had a valve job. You will also need longer push rods to get the geometry right. Also note that 455s with basically stock 6X heads make more power with 1.65 rockers on the intakes only.
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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; 03-27-2024 at 04:25 PM. |
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