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When the new 1967 GTO came out, there were many 67s running around with tri-powers from the previous years. Your asking about the 4 barrel but yes the 65 will fit.

Edit: The 65 manifold should fit HEADS from 64 to 71 era. Someone check me on that. Make sure someone has not changed the heads on your block.
 

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Yes, it will I owned 1965 Gto with 1968 400 block and heads and breefly ran original 389 intake [and carter 4 barrel carb, engine ran very strong, but eventually upgraded to 400 manifold and 800 cfm Quadra jet carb, pontiac engines of this era 60's and 70's, many parts are interchangeable, heads,intakes, exhaust, thats impossible with other auto makers of the same time period, engine sizes from 326 -455 interchange.
 

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Discussion Starter #7
I heard that i would need higher octane gas. If i use high test and those octane boosters with some lead additive would that work.
 

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I am wondering why you want to put that square bore manifold on the '67 though. The '67 manifolds can be found and are pretty reasonable. They work much better, especially with the Quadrajet that came with them.
 

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Discussion Starter #9
This is my 21yr old sons car. The engine didn't have an intake. He found this one for $30.00. This is his dream car. He wants it as a driver but close to the right parts. I told him an aluminum intake would give him more ohmph. We went to a local car club meet and greet club called spindles and they had a 67 there. It had the aluminun manifold and he was not all that impressed. He plans on using a holley 750 vac 2nd with electric choke. I read where all we need is a spacer to manifold for this. He does plan on someday getting the tri power
 

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I heard that i would need higher octane gas. If i use high test and those octane boosters with some lead additive would that work.
In a word, no. Even starting out with 93 octane fuel as a base, it'd take so much of the canned booster to raise the octane 'enough' that it'd probably be more than double the cost of just finding a source for 100 octane racing fuel, and the fuel would have so much 'booster' in it that there'd be very little energy content left.

Bear
 

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670's will be fine with flat tops with proper attention paid to quench, cam selection, and a good cooling system. IMO
 

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Discussion Starter #12
My son mentioned something about the quench. He thought that he might need a slightly thicker head gasket to lower compression some.
 

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My son mentioned something about the quench. He thought that he might need a slightly thicker head gasket to lower compression some.
Thicker head gaskets will only increase the quench area. The consensus on the quench area is .040" to .045". Most Pontiac pistons are about .020" down in the hole and a head gasket is typically .038-.040". So you are already over the ideal quench with a stock piston/head gasket. This is why you will read of many blocks being "zero decked." Adding a thicker gasket will only make this worse and this is where you can get detonation from as the quench distance increases.

In building my 455CI, the pistons are down in the hole .020" and my machinist is using a .027" Cometic brand (expensive) head gasket. So that gives me a .047" which he feels is just fine with the forged pistons I am using as they expand a little more than cast pistons.

The correct fix is a dished piston that gives you added volume in lowering compression. You can run the higher compression, but may need to run premium gas with a mix of race gas or additives - which can be pricey and you can't always get the racing gas just anywhere.

When I used to run the high compression cars on leaded Regular gas, I would back the timing off so it would not ping. I also had an 11 to 1 409CI engine that I ran on Regular, but it ran very rich with a pair of 750CFM carbs off a Ford 460CI and I had no problem. I have read that running an engine real rich can help with a high compression engine and detonation. I got 8 MPG with the car, and had to run a dual point distributor,n hotter coil, MSD ignition, and those old JC Whitney non-fouling aircraft type sparkplugs.
 
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