We often discuss the proper size carb based on flow capability (engine size & RPM), but I haven't seen this chart on the Holley website discussed: http://www.holley.com/HiOctn/TechSer...nfo/P225A.html

Basically, it helps you avoid bog. I'm borrowing a 650 DP right now to see how it does on the 396. After a couple of trips around the block, I can tell that I have to stall the converter up a little or it'll bog. Trying to nail it off idle doesn't work well, but if only stalled to 1500 (my converter stalls at ~2200), it hauls. So, be conservative in determining your minimum WOT RPMs.

Just another factor to consider when chosing a carb. Or, to put it a better way, when putting together a package.

P.S.: For a quick reference on carb size based on displacement & RPM, there's this http://www.holley.com/HiOctn/TechSer.../FMCTech3.html . The 396 would be considered "mild", so a 650 DP is appropriate. If it otherwise works well but hurts high-RPM power, guess I'll just have to do a Proform main body conversion...

 

That chart is also in the book Holley Carburetors and Manifolds by HP Books. I knew it looked familiar to me.

 

Yea Ive seen that and agree. I guess all the guys here running 750's on a barely better then stock 350, egre I mean wild 383 got it togather.

So the double pumper makes that much difference on your setup? I personally cant get one set to where its decent enough to use for more then WOT situations.

 

See this thread:

https://www.thirdgen.org/techbb2/sho...hreadid=192658

Except for an off-idle stumble, which I haven't chased yet except to try a higher-number PV (which didn't help), it runs awesome on the street & highway.