Quote:

---

I already have the 906's w/ heavy springs/dampers. The aluminum heads are just a little rich for my blood at the moment.

Also, the engine ran strong with the 700cfm right up to 6500. At the suggestion of a friend, I tried both a 750 & 850, and after tuning them both, I found the larger carbs were not as responsive, and there was really no diff in the et's, so I went back to the 700.

---

Iron heads with todays fuel and that compression ratio may not be compatable If you have to retard the timing or run the motor fatter than best performance to keep it from detonation your not getting the best performance from the parts, are you I would lower the compression to no more than 9.5 to 1 so I could tune it for best performance As far as your motor not liking the bigger carb. that is a abnormality with all the 440 I've tuned and tested, I would bet money that you had a fuel restriction in the car limiting the fuel supply at WOT on both carbs My reasoning for saying this is I have tested carbs. from 600 CFM to a 1050 Dominator on the same motor, one intake swap for the Dominator carb. and the car would pick up with each larger carb. All the 4150 carbs, 600 DP Holley to a Holley 950 HP DP, where tested on the same intake and jetted for best performance I even tested a BG Holley 750 stage three modded carb. that flowed 920 CFM and it ran better than any of the stock 4150 Holleys jetted Good luck on your build Think twice, act once Edit, I should have read pages 2,3 and 4 before posting this post To late for my Good luck BTW, a colder spark plug will help control detonation. I like to set my BB total timing at 34 to 36, depending on which compression ratio and fuel. I do shorten up the advance so I can get 14 to 18 degrees at idle and then have the timing come all in by 2000 to 2500 RPM.