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

[BLACK85GT]

I would think you need at least a Performer RPM to let that 750 breath. The plain performer is not much bigger than the stock one. My car was running 13.70 at 102 with the 302 non roller motor, ported stock heads, performer rpm, holley 600 vac. And this was with 3:08 gears.

[StockRustang]

WAYYY to big of a carb.

like someone said already, performer isnt much better then the stock intake, you'd be better off with an airgap and a 650, same setup i run on my new motor im building with a .512 comp cam.

[82 GT]

I don't understand why people think a 750 is too big for a 351w with several mods. If you read my setup, you will see that it's a 351 and not a little 302.
I agree that's it's probably too much for the performer intake but not for the entire setup.
Remember, you can go with a lager carb with a dual plane intake since the cylinders only ever see half the carb. at any one tiime as opposed to a single plane design where the engine will see the entire size of the carb.
When I install the steath intake this week, I'll know better what's going on.

[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.

[rwhite65]

I think you can make the 750 work good for your set-up. I do not really think it is too big, but I do agree that jetting a 650 could be very benifitial also.
Ryan

[82 GT]

Hey guys, this might be a dumb question but where does the vacuum port on the back of the Holley go?
Right now, I just have it plugged. Does it NEED to go somewhere?

[HotRoddin]

I totally disagree with the 750 being to big, back in my time you could buy two 4 barrel setups straight from Ford for use on a 289 ... The most potent per cubic inch car I ever owned was a 406 with a Ford Factory 3 2bbl setup (950cfm), and I was personally involved with a 427 cammer that ran right at the NHRA national record with 2 dominators, thats 2300 cfm. So if a 750 is waaaay to big for a modified 351, then none of the three motors I just mentioned should have even run.

I'm not saying the 600 won't work, but i still think if you get that thing running like its capable of, then way out on the top end you're going to be approaching the edge of the envelope for a 600, you aren't going to get the top end push from a 600 that you would from a 750, with your combo.

Bottom line IMHO the size of that carburetor isn't what is keeping you out of the 12's, you should be able to get there with either of your carbs.

Keep tuning man, you'll get there
Rod
PS: as to that vac port, if you don't need it, plug it.