[Mike Davis]

Originally Posted by ponyakr

"...On a legal 400CID 69 GTO SS car I helped a guy with years back, we...used the same 800CFM Q-jet."


I just noticed this. An 800cfm Q-jet is not legal on a '69 GTO. All came with a 750. So, only 750 Q-jets are legal. Can't make the throats any bigger. Can use any GM 750, or an Edelbrock 1901. Mods are limited.

The primary Venturi in the E-1901 is listed as being slightly larger than the GM 750's. Don't know if that is enuff to help or not. Apparently not, since most of the Stock/SS Pontiacs I've seen are running Pontiac Q-jets. I assume that if there was a measurable performance advantage, most would run the 1901.

I also just noticed that the hp factor for the '69 350hp GTO, in SS, is only 306. That might make a '69 350hp GTO a decent choice for SS. The factor is 310 for GT. Don't know why the difference.

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

This brings up a question. How much can be gained by using an 800 Q-jet over a 750 Q-jet, on the same Stock/SS engine ? If the gain is enuff, that might give a '75-up Pontiac combo a slight advantage, since they all had 800's. Maybe Cliff can help out with this question. I think I've read that he's built some Q-jets for some Pure Stock cars, and maybe some Stockers too. He has probably done some dyno work & strip testing, comparing his 750's against his 800's.

The car was a legal car in early 90's and had sat for a few years, not sure what carb was run at the time it was campaigned in NHRA SS. The guy I was helping bought the car turn key from a guy in the North East with hopes and dreams of running NHRA Divisional events but health issues never let him. I have tried to locate the car several times to buy it but have had no luck. His name was Marvin Burke and he died a few years after that. He lived near Clemson SC.
The point was we used the same carb on 3 intakes to keep it a fair comparison. The carb was a Q-jet built by my father and loaned to him for intake test. I was trying to show the intake differences..