Hey, I was thinking of getting a Barry Grant Speed Demon 650 at some point and I was wondering if that is to much carb. for my 289.

 

i recall a few people saying 500cfm was the ideal for the 289. Someone else can confirm that probably.

 

i dont think that 650cfm would be too much. What kind of intake manifold are you using?

 

Right now I am running an Edelbrock Performer intake.

 

Oh yes, 650 is WAY to much. Actually, 500 CFM is alittle too much, but it's the closest thing to it. I believe you'd get better performance with the 500. So you are right Shifty.

 

So I should just stick with my Performer carb.?

 

If it's a newer performer, I'd keep it. More then likely it's a 600 CFM right? If it is, id keep it, and you can change out the metering valves. Those carbs are real easy to tune.

 

The intake and carb have been on it for at least 10 years now...my brother put it on when it was his car. He can't remember whether he put a 500 or 600 cfm carb. on it though.

 

hmmm. Well, If it runs good with the carb on it, I would by a rebuild kit, and different size metering valves, and tune that sucker up. ALOT cheaper that way, because Carbs are expensive, as im sure you are aware of.

 

The standard rules for choosing the CFM is given here:

http://www.musclecarclub.com/library...rburetor.shtml

From the formula given there 650CFM for 289 engine is a bit too much for mild performance, but ok for some wilder, high revving engine.

Together with hints from there:

http://racingarticles.com/article_racing-64.html

I'd say 500CFM is enough. However, I also found this article. Veeery informative. I'd recommend reading it very carefully:

http://popularhotrodding.com/tech/0511phr_carb/

From that info you can see that 650CFM might work fine as well and leave place for further upgrades, but it's easier to screw up the proper setup.