olds48

Allright,OneBadGMC(which it is BTW),I see I can't get you to bite my bait anymore.The part about throttle plates not controlling the amount of air entering an engine came straight from my Holley manual!!Can you believe that?I was looking up about powervalve ratings and got to just reading around.I don't know if I'm reading it wrong,but I typed it in here almost word for word.NO I DO NOT BELIEVE THAT.Just wondered what someone else's thoughts would be on Holley's engineering team :shock:
But I do believe in powervalves for all street driven vehicles

rabbit

Thanks for all the advice. I haven't been ignoring any of this, I have actually been taking it all in but haven't had alot of time to work on it yet due to bad weather. I however did put try the cardboard trick over the stacks and did not help. I am going to try to work (change jets up a few numbers) on it some this afternoon before the weather turns bad again tommorrow. I will let you know what happens.
Thanks again, Scott

rabbit

Thursday I drove it pretty hard and shut it down and pulled plugs they were very white after the hard run so it is pretty lean. I pulled the jets and the carbs originally came with #57's I had #62's in them (which it ran good with before the changes to the engine). I changed them to #64's but haven't had a chance to drive it yet because of the weather. Suppose to be better over the next few days and I will try it out to see how it does. Man i will be glad when Spring gets here.
Scott

OneBadGMC

Hey, imagine that. It was lean!

itsabird

no doubt, !! still sound a little lean to me, but i,m one of those that think a little fat is better than to lean.

rabbit

Well we had good weather today so I took it out and the surging is a little better and it is more responsive but it is still lean so I think I am on the right track I also have a set of Quick Fue rear metering plates on the way so that I can adjust the secondaries after I get the front dialed in. I also adjusted the points in it too (they were off quite a bit as well).

Thanks to those that have led me in the right direction. I will share a couple pictures after I take it back to the track in a couple weeks. :twisted:

Scott

edvancedengines

As has already been mentioned, the type of surging you are talking about is usually from too lean of a air/fuel ratio during cruise and part throttle. !st I would check ignition timing to see if it is too far advanced at the rpm you are experiencing this or if at all levels then it should be retarted all across the board.

What is your ignition advance curve from begining to end? At what rpm does it start advancing and at what rpm is it fully advanced? If you are using a vacuum advance canister be sure the hose is connected to a ported vacuum outlet and not to a full time vacuum source. That can really cause response problems.

Ed

rabbit

Ed I am using an older Mallory dual point distributor with the cable drive Stewart Warner tach. It has mechanical advance and I am not sure of the curve that it has. I have not messed with curves in distributors so I am not familiar with doing that. How can I find out what it has and what should it have? Sorry for all the question guys but I am trying to learn this stuff as I go.

Thanks again Scott