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 proform bodies booster dia? 
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Joined: Thu May 14, 2015 8:11 am
Posts: 164
looked around but couldnt find the info. basically my 650 body is worn out threads pulled helicoils pulling out etc. plus need some more cfm for my 7500rpm E85 330 cube engine that nearly ready to assemble.
the 650 body they say is 690cfm or there is the 650-800 sized annular body. prefer annular but think its probably a bit big.
anyone know the booster leg diameter of both these? if big enough for E85?

Sun May 21, 2017 7:37 am

Joined: Thu May 08, 2014 7:47 pm
Posts: 235
You will need more cfm. You will need a center section for E85/Alcohol the boosters are typically around .180+ where the gas boosters are not.

Sun May 21, 2017 11:15 am

Joined: Mon May 15, 2017 4:04 pm
Posts: 81 ... wU&vxp=mtr

How about this one? I doubt you will beat the price of one all set up with removable bleeds and shooters New.

It does not say the booster size though.

I agree with going to a 750 also.

Sun May 21, 2017 1:53 pm
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Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2363
Not sure what is available from QF at the moment, getting bodies is tough, they seem to be building them all when they come in. I can get billet for about $100 more than the Proform with the correct boosters installed.

Sun May 21, 2017 3:59 pm

Joined: Thu May 14, 2015 8:11 am
Posts: 164
just seeing what my options are engine is still a little way off while wait for parts & money to do so. i already have billet blocks bowls are fine thats why looking at bodies only. the 650 being E85 already will run it if needed just strangle the top end.
i had read the body they list as 650-800 flows about 830 cfm & i thought may be to big. i dont want to end up like i am now with the 650 on 257 cubes being to big.
i think 750cfm with my preference of annular booster would be ideal. but others here know better than me.
4.060 bore 3.2 stroke around 12.8 comp heads flow 271cfm at .700 at 28 inches cam is around 250@50 590 lift solid ft. dont have any more cam specs currently. 1 5/8 pri pipes high rise single plane funnelweb style so runners & plenum have big air gap underneath.

Mon May 22, 2017 3:28 am

Joined: Mon Oct 21, 2013 12:15 am
Posts: 226
Location: San Diego, CA
I would opt for the 750 with annular. You will be happier in the end. Grab a set of 12-hole billet inserts from BLP, and enlarge the discharge holes.

Booster legs should be .170" for an E85 750.

Mon May 22, 2017 10:18 am

Joined: Wed Dec 18, 2013 2:23 pm
Posts: 118
I know at some point using an annular booster in a small-venturi carb is going to really hurt the air flow simply because it's going to be an obstruction. I've been under the impression that a venturi under 1.5"-ish "should" be able to work fine w/ a good downleg, and that annulars are better suited to the large(r) venturi where a downleg is giving up a lot of response.

Wed May 24, 2017 5:53 pm

Joined: Mon Oct 21, 2013 12:15 am
Posts: 226
Location: San Diego, CA
My recommendation is based on the size of his engine, and RPM. The 650 is going to be too small, and the 750 with annular boosters would be a great compromise. If the annulars are not ideal, it is easy enough to pop them out and drive some downlegs in it.

Wed May 24, 2017 7:15 pm
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