which is better ported or full manifold? thanks

Full

There's no cut and dry answer because it too broad an issue to say one is better than the other. The best is the source that gives the best results on your engine combo...

For the street, usually full is best for mileage and drivability. If you are trying to run a huge cam, though, you'll have a bear of a time with any vacuum advance.

Ported is how I have always heard of doing. So when you punch the throttle the advance will adjust the timing with the throttle response. The only reason I would consider full monifold is for the drag strip only.

Yeah, ported was the way i was told to run it, like say with a holley you would use the port on the metering block, not the one on the base. i guess you could do it any way that would work for your combo!

Thanks guys,I just got a new 750 holley and it said ported off the metering block.The reason I asked was I was changing out the 600 I had,and I had always used full vac at the base of carb.It seemed to work fine.I'll try ported,to see what will happen.Again,thanks...

Thanks guys,I just got a new 750 holley and it said ported off the metering block.The reason I asked was I was changing out the 600 I had,and I had always used full vac at the base of carb.It seemed to work fine.I'll try ported,to see what will happen.Again,thanks...

From a ported source your idle timing will be lower and as the throttle blades are opened the vacuum will increase and add additional timing to the curve that will go away as you go wot. The manifold source add some or all of the vacuum advance (depending on vac can spec's) at idle but then acts the same as ported from there... If you have a big cam a vacuum source can help you solve idle problems and if you have a stock stall speed converter it can help that surge at stop lights in a big cam'd engine... Think of the two sources as another form of adjustibility in tuning... Use what works best.