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#1
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How much does a #15 head have to Mill, before the intake has to be milled?
I have a stock 1970 #15 Head 87cc. Can I mill .050 off of it with out any problems?
if not how far can it go? Thanks Greg |
#2
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Quite a few variables but generally you can mill .020 and not have to do anything. Milling it more and you usually have to grind some on the intake manifold bolt holes. Milling .050 might be okay with just grinding on the bolt holes. You can get an idea by mock assembling the heads without head gaskets (they're usually .040) and test fitting the intake manifold with its gaskets in place.
Last edited by PAUL K; 10-27-2019 at 08:47 AM. |
#3
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Quote:
Thanks Greg |
#4
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A 75 cc head might loose two cc just by performing a valve job. It would be easier to work with the 75 cc head.
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#5
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Did you have the # 15 head cc'd? They are advertised at 87 but can easily be in the low 90's in reality.
__________________
72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
#6
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Quote:
Greg |
#7
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Just mill the intake side of the head an equal amount and you should be golden.
The 'vintage' (40-years-old) advice from HO Racing and Nunzi, back in the day, was to mill both the head/block surface AND the head/intake surface equal amounts.
If I recall their description correctly (without digging out the book), because the Pontiac block is a 90* block, simply removing the same amount on both surfaces keeps the distance between both intake mounting surfaces the same in relation to one another. I've honestly only ever done this once, on a pair of 1971 455 big car heads (I think they were '66's), many years ago. We took off .060" on both sides and everything fit just fine. Good luck! |
#8
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did they get the 2.11" intake valve installed?
__________________
72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
#9
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How about just doing a head swap or maybe a set of E-heads?
__________________
Carburetor building & modification services Servicing the Pontiac community over 20 years |
#10
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That would probably be best. Although I live in KC and there isn't a lot heads out here in the middle.
Thanks |
#11
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You have a 400?
__________________
Carburetor building & modification services Servicing the Pontiac community over 20 years |
#12
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#13
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Small valves Sent from my iPhone using Tapatalk |
#14
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As posted , to start with for a street motor you need to CC at least one chamber in each head to get a base line and after that for every .006" milled off the head you will remove 1 CC of chamber volume.
__________________
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! |
#15
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Quote:
Can .035 be taken off or more on a #15 head? Sent from my iPhone using Tapatalk |
#16
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Quote:
Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#17
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My 71 HO heads have had .060 milled off. I do not believe the intake (Warrior) was milled either.
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#18
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you can always mill the heads ,install them on the block and then lay the intake on without gaskets. If the ports line up you know you need to mill the intake whatever the the thickness is of the intake gaskets.
__________________
72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
#19
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Quote:
Also remember the stock 70 455 with 15s was only rated 10 hp less then the big valve 64s.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#20
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In reality I would think theres more than 10hp between the 2 heads. Maybe i guess with a really mild cam where the engine doesnt really care about the extra flow.
__________________
72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
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