Bobchad

I had both of these options added recently and am noticing that the engine feels a little "rougher". Nothing dramatic mind you but at idle the tach bounces around a little where before it was rock solid and at 70 mph that smooth engine feel is a little rougher. My wife describes it as feeling like a race car.

It has a stumble off idle and I've got an appointment to have the carb looked at in a week or so. Otherwise there is no loss of power and gas mileage has not changed. It does not feel like a miss.

Is this a "normal" feel for the manifold and/or more agressive distributor adjustments?

Bob

Fevre

Might have a vac leak.

Taijutsu

Are you running premium gas? Also, where are you getting vac from? Your engine might want the extra vac from the intake rather than the reduced "ported" vac. This made my engine run much stronger. Hope this helps.
Rick

tnt76vette

:iagree: . Thats the 1st thing I'd check if all was well before you installed your new manifold........ :D

Bobchad

And it was. I'll get out there this weekend.

Thanks.

Surfer69

Besides what was said, I have same new setup and notice same thing. But one explanation could be the hot exhaust crossover is less effective than stock manifold so you get rougher idling when colder if you used restrictive gasket with metal plate and hole. It may affect other things. Some manifolds dont have crossover at all. Just a thought.

lars

Bob -
The Performer manifold tends to run a little cooler than the stock manifold, and the runner volume is a little bigger. This will effectively lean you out a little and will change tyour idle characteristics. You may need to do a little carb tweaking to get things tuned just right in order to eliminate the lean stumble you're seeing. You can also play with running your vac advance off of ported versus manifold vacuum to see where the engine runs with the best quality idle.