[455abody]

It started a easier today when cold but had to feather the gas for a couple minutes it was wanting to die. Once warmed up i hooked my vac gauge up and the most manifold vac I could get was 15 by adjusting the bottom carb screws. Advanced my timing to 12 or 13 baseline took for a drive I could hear some light pinging when I stepped on it. I then backed off to 8-10. I think I need a pro to check out.

[tc]

Originally Posted by 455abody

It started a easier today when cold but had to feather the gas for a couple minutes it was wanting to die. .

Now you need to adjust the open distance of the choke blade and fast idle rpm.

As for having advance vacuum at idle, I adjust my Holley carbs for a square transition slot opening before I place the carb on the engine. This carb needed more throttle opening without the advance vacuum. Having the added degrees of timing at idle leaves the throttle blades showing a square of the t slots.

[455abody]

I wanted to give an update on my 70 Goat.I have been doing some tuning on my car when I got back from the engine shop the mechanic had some vac lines going to the wrong places. He had the distributor vac line going to the choke pull off. Once I sorted that out it started much easier with the choke hooked up. Then I had the distributor vac advance hooked to a vac port in the back of the carb. Needless to say still running rough a drinking gas. Today I hooked vac advance line to manifold vac wow made a nice difference. It ran smoother more responsive and better gas mileage. Took a winter 40 mile drive temp never got past 160 oil pressure 60 pounds.car was running sweet. Cant wait to get my new DUI distributor installed next week. Thanks for all the helpful input. Brian

[moontower69]

That's good news.

Looks like a test case for why I said that manifold (unless a big duration cam) is how these motors were intended to run. Manifold vacuum leads to better throttle response and lower overall temps (especially siting in traffic) v ported. Ported was the engineers response to EPA regulations and not at all a performance enhancement.

I think of it as the timing is already there as you give it part throttle rather than that half second delay if running ported before the dizzy advances. (Obviously on hard/full throttle there's no difference between manifold and ported because vacuum drops, and just get the mechanical advance.). But most folks drive their cars in traffic and there manifold is typically better on a stock-ish setup. That's my experience.