Back from the track....did worse than last time!!

[mustangII460]

Rarely have ever used a carb bigger than a 700cfm on any smallblock no matter what the mods were.

My favorite carb as of now is the speed demon 650. We've gone well over 400 Hp with them. 302's 351's .

A simple guess doesn't work. There is too many factors is choosing a carb. Heads, cam, intake, compression, ignition curve, etc.

Adding a too big a carb is the single biggest mistake most hot rodders make. Ive seen this over the last 20 years Ive been building these airpumps.

Simply having camX or intakeX, headsX does'nt mean you need carbX. Your motor will only pump so much air. Adding a bigger CFM carb won't make it pump anymore. Re-jetting a carb is king.

This topic always starts a debate. "NEVER take my word on anything, search google instead." [quote of the year]

Put the carter back on and run it. Change the carb to the 750 and run it. Better yet get a 600-650 and put a bigger jet in it, I bet your time will improve. That being said, all other things must be equal.