Shoebox whats ur combo? I have that exact intake on my street car. I had 2 450 mechanical secondary carbs on it and ran 11.70 took them off put on 2 600 vac secondary carbs and ran 11.50's the 600's also had metering plates put in the back. .030 over 440 w factory heads cleaned up a bit and comp solid lift 570? lift cam 3500 converter and a whopping 323 gear. My 60ft's were a tad better w the 450's but the 600's picked up every where else. best 60 was like 1.79 and fastest mph was 119.

I have a good friend that picked up 3 tenths by switching from 600's to 660's that's my next direction but first gotta get rid of those 323's I ran it to 6600 in drive on the highway and it felt like i was holding onto a hand gernade!