ArkansasJeeper
New member
I just replaced my old Prestolite with a new (!) HEI. In-cap coil, 15 degree (?) advance can, basically right off a 1980 Jimmy.
The problem- the engine times out great, the centrifugal advance follows the curve beautifully, and without vacuum advance hooked up it runs like a charm.
The advance, though, causes the engine to lose power and backfire horribly under throttle. Is it just way too aggressive? I'm hooked up to one of the lower ports. It pulls under open throttle, no pull at idle.
I don't have a manifold vacuum port (one suggestion I read). Is it that hard to swap out an advance can? Is it even necessary to have a vacuum advance if the truck runs strong?
Thanks in advance for any suggestions.
The problem- the engine times out great, the centrifugal advance follows the curve beautifully, and without vacuum advance hooked up it runs like a charm.
The advance, though, causes the engine to lose power and backfire horribly under throttle. Is it just way too aggressive? I'm hooked up to one of the lower ports. It pulls under open throttle, no pull at idle.
I don't have a manifold vacuum port (one suggestion I read). Is it that hard to swap out an advance can? Is it even necessary to have a vacuum advance if the truck runs strong?
Thanks in advance for any suggestions.