I need some help with what carb to buy for a 1970 350olds motor, compression is like 11.2 to 1 has a 7111 intake. car is 3800 pounds with 4.10's and 3200 stall. I bought a holley 770 street avenger and it has been problematic it always seems lean, plugs are always very light colored even after rejetting 80's in primary 82's secondary. Plugs are NGK R5670-7's. cam is a comp cams 274xe. I talked to a tech at demon and he said run a 650 street demon does this sound right. car runs good otherwise just worried plugs are so light colored all the time.

 

How does it run with the avenger? I would almost think it would have been running rich? Is it the aluminum avenger or the street? Electric choke?

 

It had a choke but everything to do with that has been removed. It is the street avenger, the car runs fine 3 pumps it fires and stays running when cold if it gets hot out(we are usually in the low 70's) it runs better. Late at night in the high 50's low 60's it surges a bit and will pop until you run it for quite awhile. It runs low 13's high 12's at 105-107 depending on temp. The plugs just look really light colored. I have no burning eyes or smell at idle we run a 50/50 mix of 110 and 93.

 

I'll bet it's fine. If you don't have a lean miss, and you get all the rpm your looking for, I'd leave it alone. I have not heard of anyone using the BG carbs since the reintroduction. If you do try one, let me know how it works out. Everyone I know has been running the street avenger or aluminum avenger with very good reviews.