Thread: 78 Trans Am getting some love

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Originally Posted by 53 Chevy5

I think I may have over carbed the engine, I maybe should have gone with the 650 cfm vs the 750 cfm.

750 is a good size for your motor. I have dual quads on my 383 (1000 cfm), it’s all in tuning.

Originally Posted by 53 Chevy5

I have the jetting down as far as I can go with both needle and seat and the best I can get my AFR at 55-60 mph on a flat road is in the low 12's .

What primary jets and rods are you using. Keep a log of all changes and what they do (you’ll thank me later)

Originally Posted by 53 Chevy5

While I had the carb apart I swapped the secondary jets to the smallest size at the same time because I could see the writing on the wall. I got that from a solid 10 to about a 11.5 at WOT still plenty rich and it's got a noticeably better pull than before better but I can still tell it's wondering what to do with all the gas at that point.

Wait on the secondary jets, most of WOT comes from the primary and the enrichment circuits. Secondaries effect on WOT is about 15-20 seconds out. Most of the rich your seeing is from the accelerator, primary and enrichment circuits, lets tune them first. Move your accelerator linkage to the furthest out hole and see how it performs.

Originally Posted by 53 Chevy5

I messed around with the timing from 34 -39 and it doesn't make much difference with the AFR.

Watch the timing for detonation at WOT, 39° is pushing it and may actually lose power.

Originally Posted by 53 Chevy5

I'll call Holley and see what my options are at this point which I'm sure will be a smaller carb.

I doubt they’ll recommend a smaller carb, again, tuning is the key.

Originally Posted by 53 Chevy5

On a side not I got my idle vacuum up to 16 and an AFR gauge is the best investment to make tuning a carb!

Good job on the vacuum. AFR gauges are great! Just remember a miss fire will read lean, always check and read the plugs.

Originally Posted by 53 Chevy5

Have a safe and fun 4th everyone, I think we're going to take Rita out and drive around for the rest of the afternoon and try to find something to do.

I’m changing oil, plugs, wires, cap and rotor on mine today. In the morning I’ll finish with cleaning the air bleeds and changing the coolant, then out I go! Lol!!!

Happy 4th to all!