[71pp'sGP]

proud owner of a 71 gp, I know nothing about grand prix's but i had to have that car........the guy who's doing the engine told me he was going to put a mild cam in it cool....my question is, are the stock intake Performance good enough to keep it and just paint it blue with a Edelbrock carburetor (600cfm or do i need bigger) or go with Edelbrock intake and carburetor.....any suggestions..... more pic's soon thanks

[steve25]

In a race built motor the stock Intake will pass enough air to make 500 HP, so you will be just fine with a mild cam.

Stay away from that serise of Edelbrock carbs, to keep it short,they suck!

If you have the stock Q-jet carb get it rebuilt with parts made for todays Alky cut gas.Cliff, a fellow from this site can help in that regard I think.

Also your fuel pump and all the rubber hose in the fuel system needs to be up greaded to deal with the 10% Alky also!! Make sure you get a new fuel pump, not one who`s box is covered with 10 years worth of dust!

If you do not have a original Q-jet then get a rebuilt one, with out a Q-jet you are tossing out 150 cfm of air flow over the 600 carb!

[chiphead]

Love the darksider! (slang for big pontiac that's not a GTO). What size engine? Do you know what cam he's going to use? One man's "mild cam" is another man's "wild cam". The Pontiac valvetrain is really finiky when it comes to modifications. You gotta set it up right or it'll break stuff. What heads are on it? If it's a high compression engine then you've got to be even more careful with parts selection.

I would keep the quadrajet carb if it's still on there. It's a much better carb when set up properly than most of the edelbroke units. The Q-jet is rated for 750 cfm and provides superior throttle response on the street. The trick is finding someone who understands them. Many Quads were tossed in the trash simply because the mechanic didn't understand how they work.

The stock 4bbl pontiac intake from '68-71 are the best of the stock intakes. '72-later had smog/egr passages and get restrictive on the secondary openings. These '68-71 intakes aren't 'high rise' like an RPM, but they had good plenum volume and runner size for even 455s. The idea that "stock sucks" came from the big block chevy engines of the same era. Their intakes were a totally different design that really did hurt power. The pontiac factory intakes are spreadbore, and will not accept a squarebore holley or edelbroke without a goofy adapter. I avoid the adapters because they add sealing issues and port flow issues. If you want to run a squarebore, go with an aftermarket intake like a performer, performer RPM or other aluminum intake.

[cutrone]

Nice looking Grand Prix !