Proform 750 DP

[MomsDuster]

Hey folks, I'm looking to purchase a Proform 750 double pumper for my 440. Still on the fence on whether to get the street w/choke or the race w/o. Not convinced i need a choke seeings how I'm in California and i don't drive it in foul/super cold weather. But also not convinced that the extra $ is worth the added flow and cooler looks of the non choke version. Also I'm planning to put a tunnel ram on it in the future so correct me if I'm wrong from what I've read 750x2 would be acceptable. Any input gladly accepted. This should be interesting.


The engine is a 440 100% street driven, may see a track just out of curiosity some day.
915 heads with some porting,
Comp XE275HL w/1.6 rockers and B3 correction kit.
3k stall,
3.23 rear gears,
TM7 intake and 800 avs2 carb.

 

[Garrett Ellison]

sThe single 750 will be a little small for the 440, but you'll probably have stronger performance with the dual accelerator pumps. If you don't mind babysitting the engine for a minute or before it idles down, running without a choke is fine. I oftentimes don't use one, and it does get cold and foul here quite often. Two 750 double pumpers on a tunnel ram is as good as it gets on the street. Popular consensus is that a Weiand Hi-Ram is the best TR intake for street use. With your 28 inch diameter 275/60-15s, I would be looking at a little deeper gear before making any other changes, though. Which gear is going to depend on how far you're going drive it, but I would start with 3.73 as a minimum and be leaning more towards 3.91-4.10 if I didn't plan on any serious distance driving.

 

[yellow rose]

No choke and VERIFY what ProForm sent out as far as the carb calibration. I’ve had some not even match what is on the paperwork.

Also, you’ll probably need to cut the emulsion back a bit. Every one I’ve done has too much emulsion.

If you’re not sure how to check and fix it, PM me when you get the carb and I’ll walk you through it. You just need some 6-32 x 3/16 brass set screws. You most likely won’t even need an 80-61 drill index.

 

[MomsDuster]

Would an 850 be a better option? Or would that cause issues if/when it comes to adding another one on a tunnel ram?

 

[Garrett Ellison]

I would think it would be a bit excessive for a mostly street driven car, especially with the probable flow numbers your heads would make.

 

[j par]

First thing I did was make sure you've been on the forum for a while and you have. I was just hoping you were safeguarded against having a self-proclaimed carburetor Guru take you down a rabbit hole...
is there any reason you would just buy the tunnel ram instead of another carburetor and just buy another 800 AVS?.. it'll be another couple hundred dollars remember putting those Holley style carburetors sideways and getting the correct linkage paid for... The Edelbrock carburetors are much easier and cheaper to connect together..

 

[yellow rose]

First thing I did was make sure you've been on the forum for a while and you have. I was just hoping you were safeguarded against having a self-proclaimed carburetor Guru take you down a rabbit hole...
is there any reason you would just buy the tunnel ram instead of another carburetor and just buy another 800 AVS?.. it'll be another couple hundred dollars remember putting those Holley style carburetors sideways and getting the correct linkage paid for... The Edelbrock carburetors are much easier and cheaper to connect together..

LOL.

 

[Garrett Ellison]

For mostly street driven with the remote possibility of taking to the track, a second AVS2 may be the most user friendly approach. But, it’s also a compromise. It’s up to you to figure out here if you are more after maximum performance vs more convenient carburetor tuning.
EDIT: If you decide you to stay with 3.23 gears, then the dual 800 AVS2 carburetors would also play somewhat nicer for overall street performance.

 

[MomsDuster]

For mostly street driven with the remote possibility of taking to the track, a second AVS2 may be the most user friendly approach. But, it’s also a compromise. It’s up to you to figure out here if you are more after maximum performance vs more convenient carburetor tuning.
EDIT: If you decide you to stay with 3.23 gears, then the dual 800 AVS2 carburetors would also play somewhat nicer for overall street performance.

Well seeing how I just and I’m mean within the last couple of hours just put in the freshly built Dana with 3:23’s they’re staying for awhile! The club I roll around with does a lot of out of town cruises, 100+ miles one way sometimes. The 3:73’s were just too much. That and the fact that the original builder left media blasting material in the case wiped it out in n 2k miles.