# Lets Talk Heads



## Jim (Oct 30, 2008)

I have the 670 heads on my 67 GTO.

I have been told those are the heads to have if you are going to use factory heads.

Opinions??

Jim:shutme


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## 68greengoat (Sep 15, 2005)

Here's the available heads in '67.


1967 326 250HP 140 1.92/1.64 9.2 c.r.
1967 326 285HP 141 1.92/1.64 10.5 c.r.
1967 400 255,260,265HP 142 1.92/1.64 8.6 c.r.
1967 400 290HP 143,061 1.92/1.64 10.5 c.r.
1967 400 325,333HP Big Car 143,061 1.92/1.64 10.5 c.r.
1967 400 350HP(GP) 670,9787, 671,187 2.11/1.77 10.5 c.r.
1967 400 325,335,360HP 670 2.11/1.77 72cc
1967 400 325,360HP RA 670,97 2.11/1.77 72cc
1967 428 360,376HP 670,978, 7671 2.11/1.77 72cc


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## 68greengoat (Sep 15, 2005)

I broke it down to GTO specific. In '67 you had either a 255, 335 or a 360hp motor. As you can see the 335/360hp motors used 670 heads. Check your 2 letter engine code or PHS to determine the hp.

1967 400 255,260,265HP 142 1.92/1.64 8.6 c.r.
1967 400 325,335,360HP 670 2.11/1.77 72cc

If it originally had ram air then you had these 2 options.
1967 400 325,360HP RA 670,97 2.11/1.77 72cc


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## geeteeohguy (Feb 2, 2008)

670 heads on my '67 produced more power than the #12 Ram Air heads I later installed, and the 66 455 heads I installed, and the current #15 heads I am running now. They are an excellent head. Only problem is, you need about 100 octane to run them without engine damage caused by detonation if you run the stock pistons. If you use them, run octane booster or dished pistons for a 9-9.5 to 1 compression ratio.


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## danthepontiacman (Jul 5, 2008)

so if im reading that right your telling me the valve size in the 326 250 hp heads and the 1967 400 325,333HP Big Car 143,061 1.92/1.64 10.5 c.r. ae the same size?


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## 68greengoat (Sep 15, 2005)

danthepontiacman said:


> so if im reading that right your telling me the valve size in the 326 250 hp heads and the 1967 400 325,333HP Big Car 143,061 1.92/1.64 10.5 c.r. ae the same size?


Yes. The 326 250hp has 9.2 compression and the 400 has 10.5 compression...


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## danthepontiacman (Jul 5, 2008)

so if i raised the compreshion of my 326 to 10.5 id get close to the 325 hose power the higher compeshion heads got? or are the chambes in the heads a diffent size? i got a 326 and i was going to buy a set of 325 horse full size heads from 65 but if thare the same size it be a waste of cash


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## 68greengoat (Sep 15, 2005)

danthepontiacman said:


> so if i raised the compreshion of my 326 to 10.5 id get close to the 325 hose power the higher compeshion heads got? or are the chambes in the heads a diffent size? i got a 326 and i was going to buy a set of 325 horse full size heads from 65 but if thare the same size it be a waste of cash


No. Don't forget you have alot less ci in your 326. There's a calculator available out there that some of these guys use to figure out hp ratings. They should be able to tell you what you would need. I would think, tho, that you would be hard pressed to get 325hp out of a 326. Plus, I thought I read somewhere you're running a 2 barrel carb. But, I'll let the experts weigh in on that one....


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## danthepontiacman (Jul 5, 2008)

well i am but if i can get 300 horse power that would change a 67-72 intake with a better cam and a 750 q-jet would awaken it, a 326 is less then a 389 but it has the sam stroke the same basic blockand the same rpm range, it mite not make 325 h.p. but i am sure it would make 300. i mean its what 63 cubes smaller that aint alot. its jsut ahd for me to beleave how many folks knock a 326 when its basicly the same has a 389 400 and 455 i mena people build 300+ h.p. 327 chevys and i know a pontiac v8 is more capible then a chevy.


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## danthepontiacman (Jul 5, 2008)

if i nkew were that calculator was i would liek to use it if naybody knows where i can find it???


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## danthepontiacman (Jul 5, 2008)

i wouldint be had pressed to get 325 horse pwoer from a 326, ive seen a 326 that ahd not been bored and thay were makeing 400 horses with pontiac heads and intake but it did have a msd coil and stuff.


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## danthepontiacman (Jul 5, 2008)

another point i wish to point out is you say its to small a engen to produce that kinda power and that you would be had pressed to get 325 hp out of it but thats only 66 cubes smaller then the famed 389, the ford 302 is 88 cubes smaller then the thunderbird 390s that were built in the 60s yet the thundebid 390s ive sen produce 325 hp while a creat 302 can produce 340 horse power NOTE thats 15 more ponys fro ma engen that is 88 cubes smaller. now for chevrolet, the famed 327 chevy a engen that is only 1 cubic inch biger then a pontiac 326 made anywhere from 250,275,300,325,350 and 375 hp in its run from 62-69 so tell me this why do you think a pontiac 326 cannot make 325 horsepower ha i bet it can be woked on and make has much hp with a q-jet has a gto can. just felt you needed some comparison info and oh lets not forget unlike ford or chevy almost any pontiac intake or heads will fit my engen has long has thare made betwin 59-79


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## even steven (Feb 27, 2009)

remember the old saying"horsepower sells cars,but torque wins races"


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## danthepontiacman (Jul 5, 2008)

I would think, tho, that you would be hard pressed to get 325hp out of a 326) well why do you think that when a 326 is only 63 cubes smaller then a 389, a ford 302 is 88 cubes smaller then the ford 390 yet the fod 390s that were in the t birds in the 60s had around 325 h.p. while a creat 302 can push out 340 h.p. and what about the chevy 327 witch is only 1 cubic inch bige then a pontiac 326 and in thae run from 62-69 thay made 250,275,300,325,350,375 and even 360( the later of theme was a f.i. one) but still if a 327 chevy a engen that is smaller then a pontiac engen and only one cubic inch biger then mine can make that kinda power and the 302 compaired to the 390 can do that then why do you think a pontiac cant do it with pontiac heads and intake afteall has long has its a pontiac v8 made from 59-79 it will fit so why do you think it cant be doen without boreign the engen supe chager or puting multiple carbs on thare? care to give em the reasoning to your thinking now?=]


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## 68greengoat (Sep 15, 2005)

To be honest Dan, I don't know why you asked the question in the first place. You seem to know the answers by all the replies you have posted. I was going off your current setup with a 2 barrel carb and upgrading your heads to 10.5 compression. You can turn practically any engine into anything you want as far as how much power you can produce. All it takes is a few bucks. Look at all the ricers and what they do with them. I had also asked the experts to weigh in. You were the only one, except for one other guy, that replied. Apparently, you must be the expert. Which is fine, because I'm not. Another thing. I don't know if it was this thread or another one, but you were concerned with gas mileage. Why do you want to create more hp when it seems like your concerned with getting better gas mileage? By the way, it's a rhetorical question.


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## danthepontiacman (Jul 5, 2008)

i didint mean to post that many times my computer has been giveing me a lil trouble lately and i was asking i mean heck i nkow a 2 barrel wont but why would ikeep the 2 barel if i was going to change heads and stuff? well dude dont get mad i just hate t osee folks akt liek a 326 and 350 pontiac are both junk engens to small to mess with when all the gto goodies fit theme to, it would be like saying a 57 chevy 150 is junk cuz it aint a 210 or a bel air i mena it just is upsetting. i was just trying to prove a point that it dont cost more to mess with a smaller pontiac v8 since all the parts fit and cost the same has thay do on a gto and that it can be made a good runner. i dont have all the answers i simply was trying to milk feedback out of a few folks about the details of it. it is inportant to note you never sead with current setup so i asumed you were another one of the folks that just asums it aint worth messing with and want even talk bout it. and thare is a balacne between geting mpg and horsepower i want to find the peek were i can get the best of both my car can do.


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