hei dist vacuum advavce vacuum source

2

27lizzie

Member
I am using a chev HEI dist with Vacuum advance in my 8BA. Would this set-up use ported or manifold vacuum ? Thanks Marlon
 
ported, coming from the carb port, the port above the throttle plate, that way it only has vacuum advance as the engine rpms come up, from the manifold the advance will go full advance at idle and drop off as the rpms come up
 
WestCoast said:
ported, coming from the carb port, the port above the throttle plate, that way it only has vacuum advance as the engine rpms come up, from the manifold the advance will go full advance at idle and drop off as the rpms come up
Click to expand...

What youre talking about is venturi vacuum to me and for loadamatic and OEM carbs only.
Ported to me means you have no vacuum at idle to deal with polution issues and as soon as you go to high idle full vacuum comes in and then work as manifold vacuum.
For the HEI use manifold vacuum !
 
mine doesn't it comes from the port on carb above throttle plate, manifold vacuum is for the loadamatic dist, the advance works just the opposite of vacuum advance
 
WestCoast said:
ported, coming from the carb port, the port above the throttle plate, that way it only has vacuum advance as the engine rpms come up, from the manifold the advance will go full advance at idle and drop off as the rpms come up
Click to expand...

WestCoast said:
mine doesn't it comes from the port on carb above throttle plate, manifold vacuum is for the loadamatic dist, the advance works just the opposite of vacuum advance
Click to expand...
Can't figure out what any of this nonsense has to do with running a "chev HEI dist with Vacuum advance":confused:
 
I'm not either of those mentioned but manifold vacuum should be used with the HEI. The reasoning is thoroughly explained in my book.

JWL
 
WestCoast said:
mine doesn't it comes from the port on carb above throttle plate, manifold vacuum is for the loadamatic dist, the advance works just the opposite of vacuum advance
Click to expand...

This is not related to the HEI, but the load-a-matic does not use manifold vacuum (or ported vacuum either for that matter), it requires a specific carb designed to work with it.
 
Stock passenger car HEI cans have WAAAY too much advance, as they were used with EGR. usually # of degrees is stamped on the bracket holding the can. Heavy trucks got a can that is right for non-EGR chevies and aftermarket ones are also available. You'll probably be tinkering and blocking some of the travel anyway, so no big, but don't try to run one as is with the huge vac travel!
 
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