[Gary H]

I'm porting a set of 66" 093 heads for my 66" GTO that I'm restoring. These heads have the A.I.R boss in the exhaust port and I'm wondering what the consensus is on removing it for better flow. So, leave it, reduce it, or remove it?

[25stevem]

Grind it out of all of them.

The center exh ports need about 40% more work time in specific areas then the end ports.

Is that the final valve job?

It looks like just a 45 degree?

Just a 45 seat does not make the best use of the amour of throat area that the valve bowl has.

[Gary H]

Originally Posted by 25stevem

Grind it out of all of them.

The center exh ports need about 40% more work time in specific areas then the end ports.

Is that the final valve job?

It looks like just a 45 degree?

Just a 45 seat does not make the best use of the amour of throat area that the valve bowl has.

No valve job yet. Just hardened exhaust seats. Can you elaborate on the additional work needed on the center two exhaust ports?

[mgarblik]

I had to run 093 heads in the early days of NMCA on a 421. I removed the entire AIR boss, and tear dropped the valve guides. The chambers are very intolerant of the lousy fuel . Had to run race gas pretty much all the time mixed with unleaded premium. Limited vacuum advance to 8 degrees. Total of 32 degrees was all it would stand with the mix of fuel. Put allot of time and effort into those heads. Just wouldn't flow enough air for a 421. Did manage to barely get 430 HP out of it with a 276-284 Ultradyne hydraulic flat cam. They had a minimum vacuum rule in those days at 1000 RPM. It made 19".

[25stevem]

Gary I sent you a pm.