Hemi running problems

I have a 528 Iron headed 10 to 1 Hemi. Comp flat tappet hydraulic .535/.541, Mancini ready to run dizzy with a MSD blaster SS coil. Mopar performance high rise intake with a single pro systems 4150hp carb . Timing set at 32 total vacuum can capped. Car starts fine hot or cold. Runs strong but does not like low speed running. Likes to buck and surge at light to medium throttle. Vacuum is 10. Plugs are NGK R5671-9. They all seem to be firing but are black and sooty. Power valve is 6.5 with 84 mains. Trying to sort it out in a positive manner. Thanks.

Put a #7 or #6 heat range plug in it and see if that helps you or not
Also adjust the idle fuel mixture with the motor warmed up to driving temps and adjust the idle fuel feed to get it as lean as you can and have it still idle and go from neutral into gear without stalling

Thanks. It is a manual 5 speed transmission. Just looking at what would of been used in a stock 69 they are heat range 4. I may be way to cold. I feel I am fighting multiple issues. What do you think of the power valve with my 10 inches of vacuum?

If you have a plug, plug the power valve see if part throttle is better. If it is then lower the power valve to keep it out at part throttle.

If its pump gas I have seen certain blends try and vapor/boil when driving causing almost flooding type conditions. Seems to happen with winter blend pump gas.

check float level, maybe lower to delay main circuit at part throttle.

You could be on to something there. I was charging the a/c and going over the basic adjustments when I noticed steam like smoke coming out of the bowl vent. I thought that was very odd. It also seems the hotter it gets or the longer I run it the worse it seems. I filled this tank when I calibrated the fuel gauge end of March first week of April. I have run about half of it out. I may just drain the rest for the mower and fill with new premium.

I did do that last fall when I first got it running. I can recheck to be sure.

I do not have a plug.

What size carb? Bet its a tad rich at idle and big time lean else where if not way under sized. Typically a Hemi likes a bigger carb than the book calls for. Our 474-484 Hemi's like 950 to 1050 sized 4150 carbs...Use the Proform race carb jetting. We find their calibrations to be very close for all our builds in 4150 size carbs.

I had a Prosystems 1000, and it would idle and drive around town, but if you stepped on it, it went so lean it nearly stalled. I put the same calibration in that Proform had for their carb of the same size in the Prosystems, and what a difference. I would start there...Also, I am anti power valve and always jet my stuff square.

I am not 100 percent sure. Muscle Motors had it built when I made the deal. They did dyno the motor with it. I took it apart today and made notes what was in it. I might try to call Pro Systems to see if they can tell me. It is the Pro Series XE. One would assume it would be adequate. But assume usually it what bites a guy.

Exactly what first caught my eye on the one time I came across this also. I forget what we put in it, it was either 100 unleaded race gas or bp premium...been a while but it fixed it. It was actually causing the carb to flood, was like the needle and seat couldn't deal with the vapor.

This is BP premium.

That plug is WAY to cold for your application. I would START there

still could be winter blend...and I could be wrong on what it was, but I wasn't the only one having those problems at that time. Different blend fixed it. I didn't think it would, but someone more familiar with the problem keyed me in on it.
Fresh set of hotter plugs couldn't hurt either, but then you'll lose track of what changes did what.

Change the plugs before you do anything else.

Thanks for all the replies. I have used and like NGK plugs. No nitrous so should I run a projected or non projected tip. A stock motor in the day ran a heat range 4. This is all street with an occasional romp on the throttle. Is heat range 4 to hot?

I bought a Pro Systems [4150] carb and it wouldn't idle at all out of the box took a lot of tuning. WOT was good.

By chance did you re-curve your distributer - sounds like you may need some more initial timing on it - that ready to run dizzy has a big curve that usually needs tightened up a little

What did you do to make it work. Mine idles and wide open is fine. Just low speed surge and jerk along with hesitation at light throttle tip in.

I have it all in by 2,500 rpms. 32 degrees. Not running a vacuum advance. So base and mechanical all in around 2,500.

check the timing at idle that will give you the initial - I run on my street car 24 at idle and all in at 2000 RPM at a total of 34 really helped with the stumble and cleaned up the bottom end

have you checked your distributor for sticking weights or advance plate ?
some of the ready to run units i have seen have little to no lube [they don't need much, but a "little dab 'll do ya"] and will sometimes start to rust a tiny bit, causing stickyness.

To easy. All good there working as it should.

I've always run NGK R5671A-8 (4554) plugs in my pump gas hemi when running it naturally aspirated. I would think an R5671A-7 (4091) would be fine for yours.

I drained the tank and kept samples. Old fuel like a light whisky color. New fuel clear like moonshine. Raining so no test drive. I did start it and maybe it is in my head but it seems to feel and sound better. I do not think it will cure everything but I wont know till I drive it. After that it will be plugs.

What did you replace it with, same stuff just fresh/summer blend? Or did you change brands/types?

[/quote]
What did you replace it with, same stuff just fresh/summer blend? Or did you change brands/types?
[/quote]

Different brand Shell v-Power premium 100 octane. Not much to choose from in my small area. I would assume it is a summer blend.

100 octane I would assume that a seasonal thing? Around here we get 100 but it's only available in the summer.

My bad in a hurry. 100 percent ethanol free 91 octane is what I ment to say. Drove car today and it is running a lot better. That gas was junk. At least now I can work on fine tuning it. I think that I need some adjustment. Driving a cammed big inch Hemi with a carb is a lost art. Diesels and EFI behind a stick have better manners. So some will be me adjusting and the small changes I make should be noticeable. The way it was running there was to much wrong at once. Hard to believe that I put 19 gallons of premium junk in it.

A long time ago I used to drive my charger to the track and race it, I would always stop at a local station that sold Turbo Blue. It was the same tank as they sold kerosene in the winter. Well I was there early in the year and they must not have cleaned the tank out and I got a lot of ribs in the staging lanes because of the smell from my car, smelled like I was racing an oil furnace.

That v-power fuel is real good stuff. Used to use nothing but, til all the shell stations were taken over by BP here in lower MI. It has the smell of race fuel as it burns. I run a 6 heat range plug in my 12.5:1 511. I would get a fresh set of 6 or 7's projected tip plugs and get them in there as others have suggested. You say 10" of vacuum. Is that in drive idling? What duration at 50 and lobe sep on that cam? Dom@Thumpercarbs could get that carb right for you as he has fixed a bunch of ProSystem carbs. I ran one of Dom's 1100 Dominators on my street/strip 511 and you wouldn't believe how clean it ran and never a hiccup on accell.

That was my thought also that the color could of been a winter blend like you said or a truck load accidentally mis-blended fuel. I have a friend that drives tanker for Klem and he said it is all pre-determined when he loads. So who knows. This was a first of this for me. We will see if the lawn mowers will run on it. If not to the burn pit in the fall at camp.

wonder if because it's kind of a specialty gas that it was old at the time of buying...they probably don't sell much ethanol free over the winter and you got some of last summers batch.

This place moves a lot of fuel. Re-looking at my parts receipts I got my fuel sender calibration box around April 10th. So my first buy would of been around then for the low side calibration. And the rest within a day or so for the high end calibration. So who knows. For now I am happy with how it changed the running. As soon as you said like fuel boiling the steam out of the vent became a vivid picture. I have samples in clear glass bottles I will try to get a picture of.