I have a 670 Street Avenger on a stock 350 in my 71 Monte Carlo and found I had to go up in jet sizes to get it to run right. It's dialed in pretty good and runs great and would probably run just as good on the Blazer. I just wish I was at the point of being able to go EFI.I have a Holley truck avenger, they are stupidly overpriced now but they do work well off road. I picked it because Holley was what I was familiar with, but it is hard to beat a qjet off road. I think the biggest problem with the holleys is everyone buys a 670 or 770 and it’s way to much carb for what they have….I’m running a 470 and it’s about perfect for a stock 350. Agree on the edlebrock, I could never get one of those to run right.