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    1972 Mustang Coupe


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  1. I haven't gotten it out on the the road yet, I am trying to get it so that it wont foul the plugs at idle. The reason I am thinking it is a reversion problem is the cam has a 108 degree LSA so it has a lot of overlap. I might have to go out and run it hard to see if that cleans up the plugs. I know that high performance carbureted cars in the past would foul plugs at idle but once they were opened up the plugs would clean up and run hard.
  2. HELLO SCACER 1. HOPING YOU HAVE THINGS SORTED OUT WITH YOUR CARB. I PLAN ON USING THE SAME HOWARDS CAMSHAFT AND A 750 OR 780 HOLLEY 4150 SERIES OF SOME SORT. I WAS WONDERING IF YOU HAVE BEEN ABLE TO "TRY OUT" YOUR COMBO YET, AND HOW IT PERFORMS. I WILL BE USING MINE IN A 73 COUGAR CONVERTIBLE, C6 2500-3000 STALL 3.89 GEARS. THANKS! Sorry I haven't posted in awhile. Got frustrated and gave up on it. The plan at this point is to drill the butterflies to .150, and add the wire restrictors, then go up 1 step hotter on the plug. The headers are open right now and at this point I am wondering if I have a reversion problem. Any thoughts? :huh:
  3. OK this is were I'm at now. I changed a plug and set the initial timing to 16 degrees, curb idle vacuum at 13", 1 1/4 turns out on idle mixture screws. Pulled the plug that I had changed and it is still too rich. Plug is dark brown. It is better than it was but still not optimum. I am going to drill the butterflies out to the Holley spec of .150 on the kit they sell. They are drilled at .130 now. Everything I have done and found so far has helped a little but not fixed the problem. If this doesn't fix the problem then I will probably have a custom carb built specifically for this combo or switch to fuel injection.
  4. Sounds like the same issue. I don't know what is up with Holley anymore. Used to be able to buy one off the shelf a be very close on tune. I did read that they have reengineered the fuel curve on some of the new carbs. Sounds like they messed up the idle circuits on them.
  5. Do all 4 corners now act the same? I believe the Ultra has screw in idle channel restrictors. If so, one may be larger than the other three, seen it before. The restrictor hole being too large may have been the problem to begin with. They typically ship with too large of a restrictor hole for street cars and modest cams, the last 4 Holley HPs have been this way. The cam having a relatively tight 108 LSA, compared to a 110 or 112, will have more overlap, roughen the idle, and lower the vacuum at idle. The idle quality is decreased as compression is lowered as well. I hope all is well at this point. Chuck Yes, all 4 corners are acting the same now. All channel restrictors are machined in the blocks. Not changeable. I think I will be able to tune it now. I just need a few days to work it. I will let you know what I run into. Thanks.
  6. I know what you mean about Holley QC. I didn't mention it before but when I first pulled the fuel bowls off I found that they were kind enough to leave me an extra float pivot screw inside the bowl that was jammed in the needle and seat mechanism. I took care of that and it ran a little better.
  7. Update: I removed carb and pulled it down, changed power valve back to 6.5 now that I'm getting 13" of vacuum. Jets are now 70 on the primary's and 73 on the secondary's Drilled all 4 butterflies with .130 drill bit. Now idling with 15" of vacuum. Idle screws have a profound effect on the idle. They are adjusted out 1 1/4 turns now. I haven't changed a plug yet to see what it looks like since I changed the setup. I am waiting for it to cool down now. I think this did the trick. I still need to look at the timing again and see if I can back it down some. I set the floats first thing. Thanks guys for taking the time to consider my problem. I hope this helps someone else that might be having the same problem. I will update this thread with any new info. Thanks again.
  8. You are correct that the main jetting and power valve opening point have no effect on idle mixture. When you turn the idle mixture screws all the way in does the engine die? Doesn't die but runs rough. Also the mixture screws aren't consistent when turned in, 3 of them have a definite effect on idle the other 1 has a minimal effect which seems to me to indicate an internal leak but I have replaced all the metering block and fuel bowl gaskets.
  9. I have already rejetted the primaries, factory jet 73 now 70. Factory power valve 6.5 now 4.5 because vacuum was at 9 until I started to tune this. Ignition system is all new with an MSD Coil and a MSD ready to run distributor. Initial timing was bumped up to 20, total 32 all in by 3500 RPM (closed chamber heads). Thermistat is brand new made especially for the Cleveland holds at 190 running. Idling at about 1000 RPM (Don't have a tach). Correct me if I am wrong but isn't the idle circuits independent of the main jets?
  10. Here is a pic of my car. I just built a 351c 4V factory iron heads with a Torker II manifold and a Holley 76750BL Ultra Double pumper carb. The carb is running too rich at idle to tune it. It is fouling plugs after about an hour of run time. I have ruled out vacuum leaks in the lifter valley and hoses. Tried tuning to increase the air bypass by opening up the secondaries with the screw on the base plate which helped but still not enough. I am pulling 13 inchs of vacuum at idle. This is a brand new carb right out of the box. The idle screws are turned out 3/4 of a turn tuned with a vacuum gauge, anything more than that and the vacuum and idle drops. I verified that the curb idle transfer slots are not open too far. I am at the point of drilling the butterflies but would prefer not to. I built this with a Howards cam and lifter kit part# MC230041-12. I don't think that this is such a radical cam profile that it should require drastic measures to tune it. I have never had a problem tuning Holley's before and I am at a stand still with this until I can get it figured out. Any help would be greatly appreciated. Thanks
  11. OK, so this is what I am thinking. I have all the pieces to put the power train back to correct specs. It is an AC car so now I have what I need to get the AC system functional again. I will be able to make the ram air functional. I will do a freshen up on the engine with full floater forged pistons, an RV cam and put a set of Aussie cylinder heads on it with stainless valves and roller rockers. Anyone know what aluminum intake manifold will work with the ram air system? I don't know what the dimensions for the stock intake manifold are, so I have no way to compare it to an aftermarket intake manifold. Next in line will be a new Moser 9" nodular iron center section with 31 splines axles. Have the driveshaft rebuilt. New steering box and any linkages, shocks, or ball joints that need to be replaced. Then I should be ready for a route 66 trip. Anyone want to go?
  12. That's what I figured so I went ahead and bought it. Thanks for the compliment.
  13. Cool - sounds like you know what's going on (never can tell what 'new' members know or don't know). ::thumb:: Hope I didn't insult you. :blush: If you're looking to rebuild an engine anyway, I think I'd agree that going back to 351C would be a good way to go (depending on what your plans for the car involve). Should be pretty straight-forward to swap it back to H-code goodness, if that works out for you. As far as over-boring goes, mine is punched out to .060". I know a lot of people think that's no good, but Hey - they wouldn't make pistons and rings so readily available if it wasn't a viable option. I'm not planning on racing my car or anything beyond an occasional burn-out to keep the Ricers at bay, so it should be just fine. So far, so good - it's not running hot or anything out of the ordinary. I thought about going back to the Cleveland engine and if I can find one for a good price that might be an option. I found a 140,000 mile Cleveland with the AC compressor and hoses and all brackets with a rebuilt FMX for $900. What do you think?
  14. Thanks for the compliment. No, the person that owned it before me did the paint and bodywork.
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