PROFORM is it really good for 25-50hp ( who has one)

madvette74 · 11-16-2002, 09:47 AM

i have a 700 mechanical secondary holley, the car has unbelievable pull, at 30-35mph i can punch it and get the car sideways, lots of torq, i want to enhance performance, just a bit, will this proform acually flow more cfm than my engine needs, i got the 700 holley because i thought the 750 would be overkill, my major question is will i loose any bottem end, in the result of gaing top end hp and tq

Jughead · 11-16-2002, 06:00 PM

I've been using one for about a year now. I think the 20-50HP claim is a little exagerated. I'm using it because I needed a card body without the choke/tower. It was cheaper than buying a new carb. Honestly though, I can't say anything bad about it. It holds an idle better, has better throttle response and once warmed up really sings. Plus I like the look. I put it on my 3310 750 vac sec.

madvette74 · 11-16-2002, 09:31 PM

how did you get the rest of your holley to look silver?? also i was just about to post a message on who has a cobra gas cap,lol awsome!! i see you have one, do you have more pics of it, and where you got, i been wanting to install one for years, and i been trying to research on the parts and ect, any info would be a great help

clem zahrobsky · 11-16-2002, 09:52 PM

it depends on how bad the casting flash or die alignment in the venturi area is. i have seen 25+ hp difference in holley carbs where we were not allowed to do any cleaning up of the venturi area because of the race track rules. finding a old carb that was built before the dies wore out made the difference. :chevy

Jughead · 11-16-2002, 10:02 PM

Quote:

how did you get the rest of your holley to look silver?? also i was just about to post a message on who has a cobra gas cap,lol awsome!! i see you have one, do you have more pics of it, and where you got, i been wanting to install one for years, and i been trying to research on the parts and ect, any info would be a great help

My 3310 started out life with the silver-chrome finish---not really my preference but...

I got the fuel filler from http://www.cobraaccessories.com then look under the Cobra section. This was a very difficult project, involving a lot of measuring & re-measuring. You can read more about the adaption & installation at http://temp.corvetteforum.net/c3/the...t/index7.shtml
Without Rolling Thunder at the helm, the project would have never completed. Thanks Dave!
:cheers: :flag

madvette74 · 11-16-2002, 10:32 PM

i checked both sites out, did you also buy the base from them?? i looked at the pics of the cap it looks like a solid base, but the web site say's there base consist of a screw type with 2inch hose, i tried to downlod the doc file, but when i do it's unreadable, did you make up your own base??

Jughead · 11-17-2002, 09:50 AM

Quote:

i checked both sites out, did you also buy the base from them?? i looked at the pics of the cap it looks like a solid base, but the web site say's there base consist of a screw type with 2inch hose, i tried to downlod the doc file, but when i do it's unreadable, did you make up your own base??

All the credit goes to rolling Thunder. He had the flanges machine to custom fit our Vette's. The problem with their adapter base is that it's about 2 inches short. A new gas tank flange would need machined.

I bought the base from Cobra Accessories but couldn't use it. At the other link above I gave a brief description of the process. Essentially Dave bought a solid 6x6 block of aluminum($$) for mine & brass($$) for his. He then had a machine shop make the new flange. The base of the flange bolts directly to the tank and the flip-top filler then screws on to the new, taller flange. I'm sure there may be other ways to accomplish this and there are some guys who have the flip-top filler simply attached to the rear deck.

Dave & I wanted the flip-top to be completely functional and open directly into the tank. One thing we discovered in this project is that gas tanks vary. Some flange bases of the tank are tilted 15 degrees and some are flat. A while back I spotted a filler neck from a C2 coupe which I though might work---not sure of the dimensions & it mating to the filler cap. Maybe that's something you could check out.