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093 heads on 66 GTO

  
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093 heads on 66 GTO

 
bellyache bellyache
New User | Posts: 31 | Joined: 08/13
Posted: 03/16/14
05:44 PM

I thought I seen some where a post on water ports in the heads at 1\8 inch drilling them out to 1\4 in for more flow does anyone remember that post  

ROWSLEY ROWSLEY
Guru | Posts: 1016 | Joined: 07/11
Posted: 03/16/14
05:55 PM

have you tried a search?  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 483 | Joined: 11/13
Posted: 03/17/14
08:40 PM

i heard something around 20 years ago about drilling out the holes or something but the question is. what EXACTLY is the prob?

does it overheat at idleor on the fwy or both?

what t stat is in it?

new eng?

how far is it bored?

etc.?  

bellyache bellyache
New User | Posts: 31 | Joined: 08/13
Posted: 03/18/14
08:15 PM

overheats both and has new pump plates
robertson 180 new engine about 2000 miles
30 over flat top pistons basicly stock
been trough carb for lean and timing is 34 total
I haven't checked the damper for slipage
with a standard 180 it will at 70 deg at idle go to 210 with robertson it will hold at 187 to 190 at 70 deg
has new recored 4 core radiator
stock 7 blade fan with heavy ac clutch fan which the car did not have and fan shroud which was not stock but read something about the holes in the heads maybe not be enough to allow more flow
I believe the radiator is big enough and maybe it needs more miles but I think at 70 it should not be that hot. Last summer it was 95 and it goes to 210 stop or go
I was looking for input on the heads as I also wondered about the gaskets but the builder used felpro
thanks  

ROWSLEY ROWSLEY
Guru | Posts: 1016 | Joined: 07/11
Posted: 03/18/14
10:59 PM

your fan can not do it's job without a shroud!! the shroud makes the fan pull air through the radiator. should cool at speeds over 35mph with no shroud.

1 question what is your base timing. i'm not shur about impeller to plate gap on the older style pumps.

2 things happened in 69 crossflow radiators and pontiac changed their water pump design.

it seems we have seen a lot of newly rebuilt motors with cooling problems that they did not have befor. a new new motor will have more friction. therefor making more heat. more hp will also make more heat.

210 in 95* heat dose not sound out of line to me!  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD