switching to a proform 850

[mally69]

Switching over to an 850 proform double pumper from a mighty demon 750. my 440 Runs great now with the demon but I feel it needs a tad more. What's your thoughts on proform carbs.

Also I forget what jets are in my mighty demon 750 I'll have to check when I take it off, but it's Jetted perfectly, what size jets do you guys think I should start with in this proform 850 (roughly)

[303 Mopar]

I hear nothing but good things on the Proform carbs.  I plan to buy exactly the same carb as you as soon as I get the funds.

[mally69]

Got my carb on jetted and tuned. , runs wayyyy better mid range and top end the 750 was holding me back some. Def gonna buy more proform carbs for my next builds, nothing wrong with demon . It just wasn't big enough, and proform costed less and looks better too

[RIDELIKEHELL]

I'm going 850 as well 

[303 Mopar]

Got my carb on jetted and tuned. , runs wayyyy better mid range and top end the 750 was holding me back some. Def gonna buy more proform carbs for my next builds, nothing wrong with demon . It just wasn't big enough, and proform costed less and looks better too

Did you have to get the Holley adapter for your Proform?  Got any pics?

[mally69]

Can't poast a pic , every freaking time i try on here it says to large. Errr

[mally69]

I'm running a tm-7 intake. I didn't need any adapters of any sort

[303 Mopar]

I'm running a tm-7 intake. I didn't need any adapters of any sort

Thanks.  Try using photobucket.com for posting pics.

[firefighter3931]

Like Holley, the ProForm carburators are universal fit and as such require a throttle adapter to achieve the correct ratio with the throttle cable. The Mopar specific piece is a Holley 20-7 and it can be installed on a Proform carb.

http://www.summitracing.com/int/parts/hly-20-7

Without this part you will not be able to get the throttle blades open fully with the pedal to the floor  


Ron


Ps. Here's a pic of Nick's engine with the PF 750 and holley 20-7 adapter installed using the factory cable and kickdown linkage

[firefighter3931]

With regards to carburetor sizing ; Mally has a heavily modified engine with a .550 lift solid cam, headers, single plane intake manifold and aftermarket aluminum heads that flow much better than stock. In this case the 850 was a good choice. 

With a closer to stock engine using factory heads and HP manifolds with a stock/mild hydraulic cam the 750 is a better choice. That is what I recommended for Nick's build and he's very pleased with the results. 


Ron

[Nickrc3]

With a closer to stock engine using factory heads and HP manifolds with a stock/mild hydraulic cam the 750 is a better choice. That is what I recommended for Nick's build and he's very pleased with the results

+1 - and continue to be very, very  pleased with your recommendation(s) Ron, including your awesome FireCore system.
In fact, I hope to start the rebuilding process with my old 440 six-pak. This is how she looks from a 28 year nap.


Can any fellow Floridians out there recommend a good Mopar engine service shop within the State? I'm interested in a streetable, pump-gas, 425-475hp version w/6BBL. induction. Thinking on a 440 stroker kit w/ their Stealth heads 

[mally69]

I didn't need the Holley adapter either. My setup is totally diff I have a high sitting bracket that my throttle cable runs through that's adjustable that bolts down to the last two boltsbofbthe manifold with a sleeve and a small U shaped clip that connects to any of the small holes in the bracket on the proform or demon carb

[68charger440]

I went with the Proform 850 that Ron recomended on my 500".  After he helped me dial it in, it is purring.  I don't know what it will do on the track at WOT yet, but I love it so far.  My motor's top end is very mild with stock 906 heads, Edelbrock Performer RPM intake and Edelbrock Performer cam,  so I had to jet it down from 78 primary and 86 secondary down to 72  and 74.

[myk]

The secondaries are bigger than the primaries?  I thought it was the other way around?

[68charger440]

The secondaries are bigger than the primaries?  I thought it was the other way around?

I think it is pretty normal to have primaries smaller.

[myk]

Uhhh...I think I better go check my car....