suggestions for tuning motor

[68Valiant]

what are some things i can do to tune my engine besides timing? i want to get the best performance out of it as possible.It has the Holley Steet Avenger carb. if i swap out the springs for the vacuum secondaries, the liter springs will open them sooner or later?

[moparking]

The lighter spring in the secondary will let them open sooner.You have to be careful about going too far.If you go too far it will cause a slight hesitation,and then accelerate.The g-force after it recovers from the bog will "fool"you into thinking that it's accelerating faster than it is ,but it won't E.T. as well.What have you done with the timing?How much inital,total,when's the total all in?There are a million variables ,and each combo likes a different one.As a rule, give it enough initial to make it idle well.This could be anything from 8-20 deg. depending on your comp.ratio and cam.Try 10 to 12 for starters.Try to keep total timing to 35-36 deg. on S.B and 37-38 deg for B.B. In either case try to get it all in by 2500-2800.Once you get the timing dialed in where the engine wants it,the requirements probably won't change even with jetting or other changes. The carb.should be close enough for a starting point.Learn to read plugs,and err on the rich side if you have to, to avoid detonation.After this try staging at different temperatures.My 340 liked 180 deg.,and a friends 440 ran best at 200.Feed the engine cold{not underhood}air if at all possible.Try varying your shift points.I have found that too soon will E.T. better than too late and is easier on the engine.It will take lots of trial and error,but the tenths you can shave off are worth it.

[Walkercolt]

If you're really taking off hard, you need to get the floats for your Holley that have little notches formed into them.Why?The G-forces will "lock" them against the pick-up tubes, and suddenly-no gas.Also make sure you getting enough fuel to your engine with enough fuel pressure.