I was wondering if anyone can tell me what mods racing beat does to their holleys? Such as what jetting they use on primary and if they change the metering plate on the secondary to allow for jet change (and what size jets used). Do they change the accelerator pump volume? Is this classified info and am I wrong to ask it? Let me know. Thanks.

 

A friend of mine bought one just to dissect and compare it to a stock carb and he said they do a shitload of mods to it. Air bleeds are all different and certain vaccum holes are different from the stock holley carbs. Basically he broke it down that it would be hard as hell to duplicate unless you had pin indicators and measured each and every hole inside that carb.

 

I use a regular holley 600dp on my 12a bridge and it seems to work fine. I had to put really small pump squirters in it though. I also ported a plenum into my RB manifold, which I think helps.

 

If you put a plenum in the manifold, that makes all the difference. RB extensively modifies their carbs because their manifolds don't have a plenum.

 

I setup my carbs to run a plenum because I'm cheap. But I built an engine for a friend S5 9.7 assembly with bridge port 4port turbo plates and he bought the RB Holley 650cfm carb for it and man I couldn't believe the difference in how it responded. Came on very smoothly no jerking and pulled very strong. Unlike the way I setup the carb which is with the open plenum that likes to be wide open, doesn't like the low end of things. But I drag race so wide open is not a problem for me but for driveability on the streets that RB carb is great.