GRAND PRIX 79 Grand Prix Resurrection


Master Mechanic
Mar 15, 2015
Im starting again.

79 Grand Prix T Top
74 Pont 455
77 Pont 6x; 92-93 cc w/ 2.11 & 1.66 valves

Cam Specs
.495" lift, intake and exhaust
230° @ .050, Intake and exhaust
9.5:1 flattop piston

Going to try to document this rebirth. Ive had this car since HS when I bought it in 1998.

Not a gear head but love cars. Plan on spending a lot of time reading.

First up....Maddog Headers!
Finally, headers 20 yrs later.

Wish me luck!

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Master Mechanic
Thread starter
Mar 15, 2015
I bought this in April 1998 as a hs Jr. Immediately blew the 301 and was devastated. Luckily my Dad worked with a guy who was all about Pontiacs and didn't want to hear about putting a Chevy motor in a Grand Prix...he (Jamie) offered to build us a 455 at cost!

We supply the block and parts, bought the heads from him and he put it together.

I drove it for 3 yrs (not daily) until the rend end fell out of it in 2001.

This is where I screwed up. I moved away and she sat outside until 2014 when my now wife and I moved into apartment with a garage.

At this time, I began the search for a 8.5". First, I wasted a trip to Aurora, Il where some son of a Buick dealer in the 80's tried to sell me a non-posi for $1200. Right before we loaded it up my dad asked if we could spin dif cover off to be sure it wasn't toast. The guy was like "you cant tear these things up". We took the dif cover off and there was not clutch to be seen.
The rest of the story about this clown is for another day.

Found another 8.5" about a month later. We installed it along with new control arms and we once again on the road.

At this time I upgraded to MBI distributor.

3 years since I have started it. Not coincidentally, I have a 3 yr old.

Anyway, Im all in with it again.

OD transmission
New exhaust
Delete AC

Paint and Body has me nervous.
Entire floor pan
T top repair
T top header and inserts from gbody parts (bought)
GM A pillar with factory stickers! (bought)

My fear is that nobody will want to do the body work needed...more on this later.


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G-Body Guru
Mar 3, 2009
Nice looking GP, cool story to keep it that long and get back at it. I've had my 86' since 98' as well. Sitting outside that long couldn't of been good for the roof and floor but sounds like you rounded up the parts. Might take some legwork or research to find the right place that is willing to do the work and does that kind of work well, there are people out there, just many shops like the quick insurance work it seems. Might need some patience to get the right guy. Sounds like one healthy engine too.
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Master Mechanic
Thread starter
Mar 15, 2015
I have a line on a couple CZ, OZ, KZ, BQ, 200 4rs

1 BRF that has been quote "Missing convertor. It came from a guy that had 6 gns it was laying upside down with the pan off and the valve body unbolted. I dont know if he was going to rebuild it or if it was bad"

Im looking for a core to rebuild.

3:42 posi
400 hp
525 ft lbs

Would any of these be specifically better for me?

If Im planning on rebuild should a look for a used converter from this guy or buy a new rebuild or something?


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Master Mechanic
Thread starter
Mar 15, 2015
Whelp...I just called the guy I was going to get a core BRF 200-4r from and cancelled the deal.
I was going to be paying $400 for it and have no idea if it is worth anything more than the case.
The VB that was to be included in the deal is just sitting on top of the transmission with the pan unbolted from the transmission itself.
Scary for guy that is not well schooled.

To add to my pause, all the transmission guys I speak to about rebuilding a 200-4r are like "uh, yeah. I can do that. I did a couple in a training class"
Problem is that everything I have read about those OD trannys says they are a special breed.

If I can't find someone that says "oh, hells yes, I can do that. I have done many and this what I know about them...... ", I would buy the core and have someone rebuild it but

I'm afraid I'm going to end up sourcing one from a dealer.
I'm looking at Extreme OD's in Cincy but holy hell it going to cost me.

I'm going to end up spending all my savings on transmission and exhaust.
Paint and Body will now be WAAAAY down the road unless I can find someone who is willing to put me a floor pan in and fix my t-tops while the paintjob is put on hold.
Body now, paint later type of thing.
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