Edelbrock carb vacuum??
 

I am swapping over from a points dizzy to an HEI. What runs best, running vacuum line to the ported side or the constant vacuum side? Any ideas? Thanks Jay

I tried both ,and it runs ok both way but the ported side is the correct for the HEI , Check your advance curve at different RPM's the ported side should put you closer to the stock recomendations . Constant Vacuum will let it advance too quickly .
Here is a setup another member posted when we had this discussion awhile back.
GMC JIM posted this;
When I installed an H.E.I unit in my '71 GMC ( 402 engine) ; I had a distributor rebuild shop set the advance curves as per the GM factory manual. The specs are :- 0 degrees @ 930 RPM; 2 @ 1260 RPM; 16 @ 2400 RPM and 30 @ 4400 RPM. Vacuum advance specs are 0 degrees @ 8" hg and 20 degrees @ 17" h.g. Initial ignition timing is 8 degrees advance @ 600 RPM ( idle speed).
... Above specs are from GM 1971 Chevrolet Truck Service Manual.
... Another GM reference is the 'GM/AC/Delco Tune-up Specs Manual # SD-100. These specs call for a 10-13 degree centrifugal advance @ 2000 RPM and a total advance ( vacuum & centrifugal ) of 28 to 35 @ 2000 RPM...... When I installed my unit about 10 years ago; I used an adjustable timing lite and set the timing to 35 degrees @ 2000.........No problems and I am well satisfied with the engine performance............. Jim

:) Thanks Bill, will hook it up tomorrow and give it a go!. Jay