Anyone have any suggestions for carb jet sizes for my 70 Chevelle 505 h.p. 454? I am using an Edelbrock 750 on it. Thanks for any tips!

Tim

if its really a 500 horse engine the 750 is too small, you need a 850dp, id guess starting primary jets would be in the 76 range..

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

Knowing nothing else about your engine, I do not feel I can acurately say that your carb is too small.

As far as what jet, I would start with what ever jets Holley shipped that carb with when it was new. I have a holley book, E-mail me and I will attempt to tell you what size it is supposed to have.

Dave,
If I read your question correctly, you said you had an Edlebrock carb, not a Holley. The Edelbrock carb uses a combination of jets and metering rods to determine the amount of fuel going to the motor. The carb is basically a copy of the Carter AFB. I would start with the factory settings and if they do not seem to be ok, get one of Edelbrocks strip tune packs. They come with a variety of metering rods and jets. You may also want to call Edelbrock and ask them what sizes they suggest as a base line. The 750 might be a bit small for 505 hp, but on a street motor that realistically will never see its true rpm limits, it should work fine, and actually will give better performance in most normal driving situations.
Hope this helps,

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100

Thanks for the input. I was told by the engine builder that the 750 Edelbrock (which sure does look like a Carter AFB) should perform well on this 454. I'll start with the Edelbrock stock jets, and rods, and then go a stage rich or two for cruise and power if necessary (I have the kit with the jets, springs, and metering rods). Thanks again guys!

dave

oops! Meant Edelbrock - wrong week to stop sniffing glue!

Dave, to allay any "size" fears you have. I bolted on an 850 cfm on my 427 in place of the 750, just a borrowed carb, and I did notice a big difference starting at about 5800. So basically, I had 700 rpm ( 5800-6500 redline) where the 850 was better. Now, I've spent time with the 750 to tune it and the 850 was borrowed, installed, run, and removed. But the point is if the 454 is kept to under 6000, the 750 should be OK. BTW mine is a 430ci. You'll have to do what I did to the Holley, buy the tuning kit and start a playin". Good luck.

Hey Gene,
Thanks for the info. Since mine is a driver, I'm sure that the 750 will be tuneable to satisfaction. Thanks for the reply!

Dave