hey mod. I was just handed a holley, and i hope you can answer this. There isnt a choke horn to pull the numbers off of. I was told it was a 750., dp off a high 9s car . Where would i start looking for id numbers . Im getting a older holley, haynes manual tom. I pulled the bowls off and there were blank power valves (ie) no holes in it. 85 -99 jets .. and squareish 40 squirters. 2 50cc pumps, 4 corner idle. no vac ports. I thought maybe i could rebuild this one just for the track. If it is worth rebuilding, can the front metering block be changed so i can get a timed vac port? Ill try to post pics tom.

Sometimes the metering blocks and/or the main body have the list # stamped in them somewhere. Post up whatever numbers you can find, maybe somebody will see something they can identify.

Other than that, I don't know.

Is it a 4100 series carb? I.e. not a 4500, which would be a Dominator?

750 doesn't sound right. A car that goes 9 sec (assuming in the ¼) would need more power than 750 CFM of air can make. Unless it was an econo dragster or something.

here are the numbers that i found

on the metering plates...L8804 9109 9108

main body ...P-32

bottom of t-plate 8804

t-plate bt the front acc. pump....4057 48354

Sounds like it's been worked over pretty hard... although, it also doesn't look like it ever even HAD a choke tower.

It's list # 8804; model 4150, 830 CFM. Looks like all the service parts are available for it. Should have had 80 jets in all 4, looks like 65 PV in both.

A motor that a carb like that would go on, doesn't need ported vac advance; it needs straight manifold vacuum to the vac adv, or the dist locked out.

ok let me throw this at you then...

the throttle plates are really stiff..CAN I successfully bolt on (summit#) qft-12-850 throttle plate? and then jet it down. This plate has the vac. ports that I need.

That, I could not say....

Maybe give Quick Fuel a call and see what they can tell you. I'm guessing, not, though; the 8804 is a 4150, and that part is for 4160 (vac sec). Maybe they have a corresponding part for the other model.

I wouldn't just automatically "jet it down". A more appropriate course of action would be to TUNE it. Put the stock jets and PVs in it, follow the Holley tuning instructions sticky, and see where that leads you.

ok thanks ill give them a call and see what they think. Iwas just wondering if anybody had gone up or down a size with thie throttle plates , and if it made any difference

I think im gonna leave the PV plugs in tho, and square jet the carb. and just use it at the track.


all id have in it would be a rebuild kit and new base, still not bad for a free carb

I don't think Holley makes an 850 4160 carb. The application on Summit's site is inaccurate, I would believe. The description says 850 double pumper, which should be the right part for a 4150 830.

But, that baseplate is $165. That's a heap of cash when all you're trying to do is fix a simple binding. Take it apart, clean it up, straighten out whatever is bent, see if that fixes it before spending that kind of cash.

If you want a really nice 750 double pumper carb with a billet baseplate, get the QFT Q-750 - only $450 more than that baseplate, sure to be quicker to make power than a "free" old Holley.

I need the vac ports to tho.and that plate would servr both purposes. I have so much money wrapped up in the street avenger now, that i was looking for a carb that i could play with just at the track. Also im still at the bottom of the learning curve with holleys.

I searched but didnt find anything, has anyone swapped up or down with plates and metering blocks, as in 750 main body w/ 850 throttle plates . or any combo like that.

The main body and/or metering blocks might not support the vacuum ports. May, though, I just don't know (and have been bit by that myself with a different carb).

To free up the throttle shafts, soak the throttle plate in brake fluid overnight, and work the shafts every hour or 2.

What "vacuum ports" do you think you need?

I'm thinking you don't need ANY "vacuum ports" on the carb base, that can't be obtained some other way.

What's the rest of the motor, and the CAR?

How does it work now that you've restored it to factory condition, with the original jets and PVs in it? When you went through the procedure detailed in the "Holley tuning" sticky, how did it turn out? Now that you have it running as good as it can in factory condition and know how it runs on YOUR setup, you can make an intelligent decision as to what to do to it to improve it, since as we all know, just blindly changing parts around on a carb without some feedback from the car's performance, is pretty much a waste of time and money.

I tore it down and put it in the parts washer last night, Ill let it soak for awhile.

as far as vac lines, im swithing vac for PCV and brakes to the manifold so i wont need the big ports. I still have a vac advance dist, so i need the timed port. I also need the other open port for my methanol injection switch, it triggers off of vac.

As far as the SA that is on it now, i feel i have it tuned in pretty well,Im still a little on the rich side,but as soon as I finish putting the fuel system in, ill be spraying it w/ a 100 shot

You don't "need", and may not even really want, "ported" vacuum for the dist.

Hook it up to straight manifold vacuum and see what you get. After all, "ported" vacuum is STRICTLY an emissions hack, introduced by the factory as an easy way to lower NOx emissions without altering the engine itself; the car will run better the other way, almost always.

You can drill & tap more holes in the side of your intake plenum if you need more vacuum sources.