600 CFM vs 750 CFM...

Hey guys,

Although a lot of you guys have mentioned that a 750 CFM carburetor is not too big for a LA 360, I just can't seem to get my tuning where I want it on the 750. To back up a bit, the Scamp came with a 1407 on the original mains and rods. I now have a new exhaust and a wideband on it and have been tuning.

I've got the idle at a good spot. I've got WOT at a good spot. It cranks up fairly quickly compared to when I took ownership. But I cannot get the cruise mode or power mode lean enough. I'm at the limit of the calibration kit, and from this point it is a matter of guessing smaller mains and bigger rods, and paying for those piece-mill will get expensive.

I've been reading several threads on 750 CFM vs 600 CFM, and it appears that on an engine the size of a 360, drivability improves with a 600 CFM. As I can tell, the main difference between these 2 sizes of Edelbrock carbs is the primary venturis and primary bores. With smaller venturis and bores, the air velocity will be higher. That's going to better atomize fuel. And that seems to be where the drivability improves.

I've also read that I may give up 2 or 3 hp on the top end. That ... I don't care about. In order to achieve a 13.9 second E.T., I think maybe the 60 foot time would be better with a 600 CFM carb. And I have all the same ability to achieve a 12.5 AFR with a 600 CFM as I have with the 750 CFM.

As I see it, it would be a win-win to go to 600 CFM. Plus I have a $50 discount buying it through Advance Auto. That puts it at about $289 + tax.

Does anyone want a 750 CFM that has about 500 miles on it? I will put it back to the original mains and rods.