holley 570 on a 360?

I would put a 56 jet in, leave the sec alone and possibly run a 10.5 power valve. With a stock type engine they make a lot of vac so it may not open the valve fast enough.

I bought a 670 Avenger for my sc/360 when they first came out. Seemed like a good idea at the time and I believed their advertising. What a mistake! I do quite a bit of track time and I thought I knew my way around Holly carbs but this thing gave me fits. I had the "bog" at about the 40 to 60' mark and no matter what I did or changed I couldn't get rid of it including using the heaviest black spring. Lost a full 3 tenths off what a stock 600 had given me. A fellow racer loaned me his 750 DP just try and it worked like a charm after some tuning. I sold the barely used Avenger very cheap and although it might be overkill I still use a 750 DP - stock jetting but with size 40 squirters. Oh, I didn't have any luck with Holly's tech line either. I explained my problem and they talked to me like I was a 5 year old. Their exact words to me were "If yall don't wanna listen then this here conversation is over."