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Hey guys i'm starting to work on my chevelle again, and i'm going to take off the carb. thats on it. When i purchased the car the owner gave me a holly carb., and now i'm thinking about rebuilding it and putting it on the car. I was judt wondering if anyone could help me figure out some more information about the carb. Like what cfm and so on.
Here's one more pic.
On the choke horn there should be a couple numbers stamped. Like a 4 digit with a dash and another number, then another 4 digit number under that.
4776=600cfm
4777=650cfm
4778=700cfm
4779=750cfm and so on.
Sorry if this sounds dumb, but what is the choke horn?
The area the choke plate is in.
Hey guys i think i found it. The number reads 4779-6 and underneath that another number reads 0324.
Does this carb have vacuum secondaries?
No, mechanical.
How do u know what the difference is? Just wondering.
For one, since you were good enough to put up a pic, there's no vacuum "motor" on the side. Second, if you go to the Holley site it will be listed as a mechanical secondary, along with a bunch of other good info.
Hey Bob thanks for all the good information. Are these carbs hard to rebuild?
The carb is pretty easy to rebuild. That appears to be an older version so it will need upgraded to blow out protection for the power valve. If your engine is fairly stock you will not be happy with the carb. It is just too big and if you have an automatic mech secondaries shouldn't be in the same sentence.
I'm planning on rebuilding a stock 454 soon, and i was going to use this carb. Will this carb be ok for it? Also how hard is it to upgrade the power valve for blowout protection? And which is better mechanical or vacuum secondary?
I would think a 750 would be fine for a 454, they just don't work real well with an automatic on the street. The secondaries being mechanical come in too soon causing a very rich condition and bog. Summit, for one, sells the blow out protection kit and everything else you would need to rebuild the carb.