I looked at the specs...... I think the stock jetting is likely pretty close.

I'd start with t-slot restrictors....... Something like .065 to start, and idle air bleeds about the same.
Maybe knock the primary jets down one or two sizes.

I have 47/51/55/61/70 air bleeds

I put a 47 in and it only helped 1/2 pt to 10.5 air fuel from 10.0

I put a 70 in and got 11/0.The main jet is 84 from factory.What is this telling us?
ps:I put 80 jets in and got 11.4 a/f

Early non-HP style 4500 carb where the only tunable part are the main jets.
This is a 3 circuit 1050 #9375.
I added a "high flow" metering block, which is nothing more than a block with a provision for a PV. The stock blocks have none.

Typical fat and blubbery part throttle operation for this style of carb was corrected by installing transfer slot restrictors.
I usually install changeable air bleeds in these old carbs, but on this one I left them alone.

This carb has very nice part throttle manners now.
Maybe not perfect for a lot if street duty, but vastly improved from how it was from Holley.

That help some.just fyi this is my carb.

I don't have a pin set to check the jet size

You could try the wire trick in the t-slot feeds to see how much affect it has.

Not a professional but i would use a 55 t slot jet, 70 iab 28 mab with float set mid way or slighy less and adjust screws to flavor. Usually 1 to 2 turns. Just my 2cents

Thanks for the t slot jet info and so I need to go bigger or smaller with my rich fuel mix?I see I need to reduce the tslot jet.

is that a set screw in the transfer slot feed or is it just a brass plug?

i put 8-32 set screws in a 4150 body and it looks similar...



But yeah, i would do the wire trick Fast68 just mentioned, quickest easiest way to test that change...

I will put all jets back to factory accept the pv and try the tslot in my next step.

set screw

I do have some set screws that I will check for the correct thread size and maybe I can drill them,I have a lot of pin drills
ps:Will I need to do both pri,sec side of the carb?

Do you have a 1/16" drill bit?

Is the T-slot restrictor bigger or smaller than that?

I will have to check and may take some time.I have to find my pin drill bits

IMO you wont get that cleaned up without the t slot restrictors. Mine ran way cleaner with t slots in the mid 50's. Those t slot orifices are way big. I just could not nail the tune down the way i wanted it, so off it went to Dom@Thumpercarbs.

Start with just the pri side to make sure it's having the affect you're hoping for.

Yes on the t-slot restrictors so here's my tune.......

.040 IFR'S lowered
.068-.070 idle bleeds
.026-.028 hi bleeds
.055 t-slots and .082-.088 jetting

You need a vacuum gauge to check for the best power valve and one that comes in as you crowd the throttle while cruising at a steady state speed........too high, rich too soon, too low delayed enrichment..........

Cool thanks!!