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#1
11-12-2021, 06:00 PM
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Small rust pits in chambers of 6X
Can this be polished out or machined smooth ?
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#2
11-12-2021, 06:05 PM
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Some have put dimples in chambers....I wouldn't worry about it.
__________________
 1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds |
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#3
11-12-2021, 07:00 PM
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Hope those are the smaller dash 4 heads because by the time those seats are recut to take out the rust pitting those valves are going to be pretty well sunk. And adding 3 to 4 CCs to the chamber volume, no less taking out the induction. Hardening !
The flow loss from sinking the intake might be in the neighborhood of 8 cfm, If those heads where mine I would step up to 1.77” exh valves and get a custom 2.120” made up . Do not polish that out, just live with it .
__________________
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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#4
11-12-2021, 07:48 PM
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Quote:
Pontiac paid a little more attention to details with machined chambers from the get go. Ya gets what ya pays for.
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Brad Yost 1973 T/A (SOLD) 2005 GTO 1984 Grand Prix 100% Pontiacs in my driveway!!! What's in your driveway? If you don't take some of the RACETRACK home with you, Ya got cheated    
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#5
11-13-2021, 12:00 AM
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The deck surface is pretty pitted, too. That would concern me more than pitting in the chambers. Milling the deck surface will get it nice and smooth again. Hard to tell from that one picture, but I'd guess about .020" - .030" would clean it up.
Also, what steve25 says about the valves. Would be a lot of work to install hardened seats for everything but going to a 1.77" exhaust and a little bigger intake should work.
__________________
---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#6
11-13-2021, 07:18 AM
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If it's worth asking, then it's clearly bothering you. 6X heads are allover the place, maybe find another set.
__________________
1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop  |
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#7
11-13-2021, 07:23 AM
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All the previous being said, if you yourself have never run these heads before then the first order of business is to get them checked for cracks .
This in particular takes place from a exh seat out of the chamber and over to a head bolt hole, or water jacket hole. Especially the area around the center two exh ports. Judging by your photo these heads will need a complete rebuild new guides or thin wall guide sleeves and the whole 9 yards as they say!
__________________
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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#8
11-13-2021, 08:16 AM
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Thanks everyone , if it needs seats , I will look for another set.
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#9
11-13-2021, 08:58 AM
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Think about this again!
Another set of usable heads will cost you at least 400 if they do not need to be shipped to you as I see it. Those heads you have now need new valves anyway, so for a extra 200 dollar cost of oversized custom intake valves you will have those heads back in the game and still come out spending less money!
__________________
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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#10
11-13-2021, 11:21 AM
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Unless it was some type of class restricted stock valve class there should not be any reason to do a custom intake valve. In my 6x-4 I have Manley 2.125” valves used in small block chevy, and run longer 1.77” Ferrea’s used in earlier small chamber d ports on the exhaust. Quite a few options for length in 2.125” head diameter, I have the race Manley but often you can find similar stainless 2.125” street valves on eBay for $90-$100.
https://www.summitracing.com/parts/man-11342-8 |
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