[Cliff R]

It will be flawless provided you put the correct parts in it. Those carbs are basically a factory "high performance" part, de-tuned solely to get them thru emissions. They are missing the outer booster rings, so not tuned like the standard units. Other than lean right off idle and at light engine load they aren't lacking anyplace else.......

[bruno17]

Originally Posted by Cliff R

It will be flawless provided you put the correct parts in it. Those carbs are basically a factory "high performance" part, de-tuned solely to get them thru emissions. They are missing the outer booster rings, so not tuned like the standard units. Other than lean right off idle and at light engine load they aren't lacking anyplace else.......

Can I call you tomorrow to order parts?

[Cliff R]

Sure. We're on lock-down here and have been for weeks. With most of working America at home right now call volume is heavy. Haven't been able to get much done in the shop, but I like the parts business better anyhow........

[bruno17]

Originally Posted by Cliff R

Sure. We're on lock-down here and have been for weeks. With most of working America at home right now call volume is heavy. Haven't been able to get much done in the shop, but I like the parts business better anyhow........

Thanks Cliff,
Sent request via your website.
Cheers,

Bruno

[bruno17]

Originally Posted by Cliff R

The 7029263 carb is not a direct replacement for the factory 455 HO carb. I would correct the lean issue with the HO carb and put it back in place. It is a special carb made just for those engines. Once the lean part throttle condition is corrected nothing out there will work better on that engine.

Also make sure that you plugged the hole in the air cleaner base after the carb swap. The large front vent tube on the HO carb sealed off any unfiltered air that would enter the engine as that hole is after the air filter.

I've seen a boatload of Pontiac engines ruined over the years and the 1971 thru 1979 Q-jets (and 1970 CA emission engines) used a large front vent tube that protrudes up thru the air cleaner base.......

Thanks for the tip Cliff. I didn’t even notice the hole until you prompted me to check.
Just waiting for your parts and I’ll post an update. Added 5 oz of Seafoam in the crankcase and drove a tank of fuel through it.
That and a new PCV has greatly diminished the blue smoke on deceleration.