Wanting to try my vacuum advance on full manifold vacuum, but where can I put my trans shift modulator?? Is it safe to have it on Ported vacuum, or does this absolutly must be on Manifold vacumm(where ive got it now)???Wanted to ask this before I do something stupid and toast my tranny. BTW, Its a TH350.

i have an edelbrock and holley carbs and ive always run the tranny and brake booster off the big ported (below carb butterflys) fitting at the back of the carbs i recently started running my distributer off the intake runner as it gives me more overall vacuum and seems to run better overall...i believe its a try it and see deal as others have told me their motor runs worse w/dizzy hooked to intake runner, if it helps, do it

Hrd has it right, every engine will respond differently. Try it and see how it runs. As far as your tranny vacuum, you have to run it off of full time vacuum. I ran it off of the back of the carb, as hrd said...if there is only one fitting that is already used, just buy a tee from an auto parts store. Mine is set up like that now and works fine.

FWIW I have seen about 1-2" more vacuum from the intake manifold port than I see from the carb port. Just something to factor into your setup design.

Back in the late 60's..GM built transmissions that were fantastic. You could drive them from hell and back and never had problems-when warranty issues in GM needed to wear them out-GM used a metal tube with rubber hoses attached to the vacuum source and the modulator. Transmisions began to wear out-no one could figure it out (?). GM-placed a indent into the metal line-of course this caused the trans to have a longer upshift-which GM needed to wear out the transmissions.