| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
02-13-2000, 07:57 PM
|
|||
|
|||
The '70 GTO used a cumbersome TCS spark advance system, which gave full vacuum advance to the distributor only when certain conditions (like engine temp) were met. The '70 carb does not have a PORTED vacuum tap, and the TCS system is long gone on my engine.
So, here's my question: Should I connect the distributor to engine vacuum, or should the carb be drilled for PORTED vacuum access? I don't like the idea of using regular engine vacuum, so I thought I'd ask for anyone's advice who can help. |
|
#2
02-13-2000, 07:57 PM
|
|||
|
|||
|
The '70 GTO used a cumbersome TCS spark advance system, which gave full vacuum advance to the distributor only when certain conditions (like engine temp) were met. The '70 carb does not have a PORTED vacuum tap, and the TCS system is long gone on my engine.
So, here's my question: Should I connect the distributor to engine vacuum, or should the carb be drilled for PORTED vacuum access? I don't like the idea of using regular engine vacuum, so I thought I'd ask for anyone's advice who can help. |
|
#3
02-14-2000, 06:53 PM
|
|||
|
|||
|
Are you sure there is no ported vacuum source? I'm not necessarily disagreeing with you, I just thought they all did.
Either way, You should try full vacuum before you try anything else. You may find that it works just fine. Of course, if you have a stock 1970 engine, the compression will probably be too high and your spark advance will cause knocking unless you back your timing down. What I would probably do at that point is install an adjustable vacuum advance and connect it to full vacuum, then adjust it until you lose the pinging at part-throttle. ------------------ |
|
#4
02-15-2000, 07:10 PM
|
|||
|
|||
|
Check your carb #'s and make sure that it's origional.Most ,not all,pass cars had ported vac on the drivers side front corner.Most truck/h.d. applications didn't. personally i'd want ported vac. as the mileage and performance is better.
__________________
so many pontiacs, so little time.................. moderator is a glorified word for an unappreciated prick.................. "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein "There is no such thing as a good tax." "We contend that for a nation to tax itself into prosperity is like a man standing in a bucket and trying to lift himself up by the handle." - Winston Churchill |
|
#5
02-17-2000, 11:37 PM
|
|||
|
|||
|
The carb (7040264) has a pad on the front driver's side, but is not drilled. What size bit do I use? Has anyone ever done this before? Help!
|
|
#6
02-18-2000, 09:29 PM
|
|||
|
|||
|
There is a very informative book out titled rochester carbs, it is printed by hpbooks. This book covers perf. mods but i'm not sure if it covers the mod that you are interested in. I think i've seen this series advertised in the summit catalogs. Cost used to be around $15. Hope this will help you out. mike
__________________
so many pontiacs, so little time.................. moderator is a glorified word for an unappreciated prick.................. "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein "There is no such thing as a good tax." "We contend that for a nation to tax itself into prosperity is like a man standing in a bucket and trying to lift himself up by the handle." - Winston Churchill |
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
