ProForm Carb-few questions

[NHCharger]

I recently bought a Proform 750 DP. Did not come with any manual or exploded parts page like the Eddys. Guy from Proform said call with any questions. So I call.
Is the small set screws on the side of the body for adjusting the floats? - Uh what screws
What is the small vacuum port for on the passenger side front bowl and should it be plugged if not being used?- What vacuum port 
What are the set screws on the driver side body for?- Huh 
There are two vacuum ports on front of carb, which one for distributor and what is the other one for? Uh other one runs to your power brake set up. No, the vacuum line from the intake runs to the brakes. Oh yeah, that's right

At this point he told me that this carb is ready to run right out of the box and the only thing I needed to know was what screw was for the idle speed adjustment. Carbs and timing are my two weak points and at this point I need a crash course in both.

[69chargerboy]

 

[c00nhunterjoe]

The 4 screws is your idle mixture. On a mild 440 i reccomend screwing them all in then backing each one out 1.5 turns. Start the negine and tweak from there. One vaccum port is manifold vaccum then the other is ported. Experiment with both for distributor advance. Your advance curve and vaccum can be adjusted to your appliication. Every engine combination is different.  

I see the pink accelerator pump cam on one side and it looks like a blue on the other. Ive never had good luck with the pink cam on any big block. Check what size squirters are on the primary and secondary. nothing smaller then a 31, will probably want to upsize to a 50cc pump as well. Tuning options are endless..... welcome to the world of carb tuning.

[RallyeMike]

The float adjustment is the bog screws on top of the bowls. Since you have clear sight plugs, you can verify the float level and adjust if need be.

He said it was a"run outta the box". I'd do that first before you start playing with it.

Since this is basically a Holley, you could pick up one of the many Holley books to get tuning tips.

[fy469rtse]

What ralleymike said , tune it using Holley manual, basically a Holley but improved by proform

[Cooter]

Vacuum port should be ported vacuum for vacuum advance.

[XH29N0G]

Check to see if you need a throttle linkage adapter like the Holley 20‑7.  Someone will know on here.  My understanding is that you will so the butterflies will open fully.

[firefighter3931]

Brian, you're going to need the 20-7 throttle adapter so you might as well order one up. You'll still be able to break-in the engine without it but you won't get full throttle with the pedal until this adapter is installed. 

The vacuum port up high is a ported vacuum outlet designed for a distributor vacuum advance. For now just plug it off. The vacuum outlets on the base of the carb are manifold vacuum and give you a signal at all times....full time vacuum. Plug your vacuum guage into one of those ports for tuning the idle mixture. There will be a large port on the back baseplate and that is for your PCV valve.

When adjusting the 4 corner idle it's best to use a vacuum guage and adjust each idle circuit for max vacuum. You will only be doing this after the engine is broken in and the timing has been set up.

Looking at the side of the carb you will see a window on each bowl. With the Proform carbs you want to see fuel halfway up the glass sight. This is your float level. Looking at the pic you posted it looks like the float level is set up properly.

Stock jetting on the PF 750 is 72/80 which is going to be pretty close for your setup and good enough for the initial breakin of the engine.


Ron

[Nickrc3]

Ron, not to hijack the thread from NHCharger, but once the electric choke is wired-in, how do you determine the duration the choke butterfly remains closed? Since I reside in a warm weather state, would I simply rotate the plastic choke housing so the butterfly pulls fully open upon start-up?
Please advise.

[NHCharger]

Nick, think of the black plastic housing as a heat sink/sensor. There is a spring inside that when cold is contracted and holds the choke closed. Once car is started and starts to warm up the spring warms up and expands, opening the choke butterfly.

[firefighter3931]

Ron, not to hijack the thread from NHCharger, but once the electric choke is wired-in, how do you determine the duration the choke butterfly remains closed? Since I reside in a warm weather state, would I simply rotate the plastic choke housing so the butterfly pulls fully open upon start-up?
Please advise.

Nick, here is a quick vid that explains electric choke function & adjustment 

http://holleytv.com/?p=437




Ron

[tracpack440]