78 Grand Prix project

[G-Body_Vet]

I wouldn't want to go higher for fear of becoming bouncy and or harsh.

I guess I'll be able to attest to that one day since I have the 5664's. I think I was initially ok with the idea because the additional weight of a Pontiac and lowering the front end 2". I have the 34mm bar and a 2.25 turn WS6 box too.

What was the purpose of running them in IROC convertibles.....rigidity?

 

[pontiacgp]

I have the 5660 cut and the spring rate is similar to the Eibachs which are 660 lbs

 

[G-Body_Vet]

It's been awhile since I've updated this thread so I figured I'd post something.

I started switching the car over to hydroboost so I'll post some pics. The main reason I'm going this route is for increased braking power, a cleaner firewall and just because I haven't messed with it before. I'm not ready to buy the lines or pump yet, but I have the main components. If you're wondering, there's no weight savings by going to this set-up. It's actually heavier.

The hydroboost unit is from an '84 T-type and the brake pedal is from an '86 GN.

Stock vacuum booster vs hydroboost unit

The master cylinder comparison

And the pic you never see.....the difference in the pedals. My stock GP pedal is on the left, GN on the right. You can see where the connecting stud is higher on the HB pedal. The brackets are identical.

Quick mock up on firewall

And as always, a little blasting and chrome powder coat.

 

[G-Body_Vet]

Guess it's been awhile huh? Well anyway, after making a few changes in my personal life I'll be getting back to work on the GP. Just found the best deal ever this week. An 8.5" 3.73 POSI from an '85 442, with the drive shaft for........$350! That's just the motivation I needed to get going with the car again.

 

[Bonnewagon]

$350? There he is officer, that's the guy who STOLE that 8.5" rear! :shock: SCORE!

 

['81 Grand Prix LJ]

it's sort of a "Pontiac innuendo" for the trained eye to notice.

I dont get it lol. Anyway, the front end looks amazing, and your attention to detail is great! I can tell this is gonna be one awesome car when finished, keep up the good work GB Vet

alot of chassis fasteners were painted blue by gm. the Pontiac blue is a close match is what he was saying and it adds to the Pontiacness so to speak.

INTERESTING!!! Tell me more about that paint on chassis fasteners! I'm about to get my GP redone and i wanna know ALL the little details to put it back to factory condition!!! PM me all the info you got, please!!

 

[G-Body_Vet]

$350? There he is officer, that's the guy who STOLE that 8.5" rear! :shock: SCORE!

The guy I bought it from knew it was an 8.5" and thought it was a one legger. He found the G87 code for the 8.5" axle, but missed the G80 for limited slip possibly. I can tell it's been open before because there's blue RTV on it. Maybe someone changed it, who knows? I was going to buy it just because it was an 8.5" when I saw his ad for parting out the car. I got there to help pull the rear end, saw the limited slip tag and I was floored! Spun the pinion and each axle to make sure I wasn't dreaming and couldn't believe the deal I found! It's about damned time I catch a break LOL! Moral of the story....always spin the axles or pinion to know what you have instead of relying on an RPO code.

Pulled the cover today to take a peek and it still has the 3.73's too (41 teeth on the ring gear).

 

[G-Body_Vet]

I guess it's been awhile since I've visited this thread.....ummm since August! Well anyway....I found an outstanding deal on some RA III manifolds that I plan to pick up tomorrow. I've been weighing headers vs the RA manifolds and the deal I found helped make the choice. Let's hope they are what the guy says they are! Pics to come!

 

[85GPLef41]

Glad to hear your back on your project! Congrats on your 8.5 score and the pedals look great!! The hydroboost is something i have been tossing around for now especially if my t56 master cylinder interferes with the brake booster.. Your GP is gonna be a badass!!

 

[Bonnewagon]

Originals or repo's? Honestly I've seen so many overpriced originals that were cracked I gave up looking. Plus the repo's have subtle improvements.