Have a 6port 13b in my 85 GSL and i put a holley 650 dbp on it .Did i go to big or with the right tunning will i get good results out of it?

 

wats dbp? Is is like cfm? I see ppl running like 448 IDA carbs on em.

 

A 650 is too big for a 13b.
At 8400RPMs and 100% volumetric efficiency, the 13b will need 388 cfm.
Add about 20% for variables like temperature and engine volumetric efficiency, and the maximum carburetor size needed is about 465.

Anything larger than that is overkill, and if you're only pulling 388 cfms thru a 650, the air flow velocity is going to be alot slower than thru the 465.
Same volume of air but slower velocity - and that means a weaker signal to the main circuit .

With an oversized venturi, the low end suffers. The larger you go, the higher up the RPMs you have to go to obtain a strong fuel pulling signal.

This explains the problem of the Weber carb as applied to an engine with such a wide RPM range.
They'll deliver beautifully in the mid and up top, but down low, they suffer. And the rotary needs all the help it can get down low!

 

What size holley do you recomend

 

Holley 465, just like I said.
'Course I'm not going to sit here and continue to sell you on getting a Holley! I mod Nikkis!

 

So its a 650 double pumper? If it has vacuum secondaries, youll be fine, but youll have to do a bit of tuning on the vac sec spring. If it has mechanical secondaries, youll have problems. RB sizes for a 13B are 600cfm 4160 vac secondary,single pumper.

 

Thanks for the feed back

 

How can you tell what size Holley you have? I've got two Holleys right now that I'm going to move away from, but how can you tell the carb itself what you're looking at?

 

On the choke tower is a bunch of numbers. Theres a cross reference database over on Holleys website. Use the numbers to tell which carb you have.