BUILD THREAD my 1980 Grand Prix w/BBC 454 build thread

[TURNA]

Was never a fan of those but the actually look good on your car!!

 

[565bbchevy]

I liked the gold ones better but these give it more of a stock appearance.

 

[Rktpwrd]

Congrats on a nice score on those wheels! Sometimes it's all about being at the right place at the right time.
Too bad you weren't closer to me, I'd be very interested in taking the old N90's off your hands for ya!
😉

 

[454GrandPrix]

I liked the gold ones better but these give it more of a stock appearance.

Same here. I absolutely love the look of those gold Z28 wheels on my car. It breaks my heart that I have to remove them.

For the curious, here is a side-by-side shot of the back side of these two wheels:

On the left, you see the N90 spokes are almost entirely on the same plane as the wheel mounting surface. Yes, there is a small dip right next to the mounting surface, but by the time you get out to the wheel rim that dip has completely disappeared. They barely fit over the tiny stock brakes. By comparison, the T-Type wheel drops off a cliff right after the mounting surface, leaving all kinds of room for huge calipers.

Another fact for the curious: this 15x7 alloy Z28 N90 wheel weighs 20 pounds. The T-Type wheel--also a 15x7 alloy design--weighs 27 pounds. 🙁

 

[Bar50]

Do the Monte SS wheels have the same backspace as the Z/28 wheels?

 

[565bbchevy]

Another fact for the curious: this 15x7 alloy Z28 N90 wheel weighs 20 pounds. The T-Type wheel--also a 15x7 alloy design--weighs 27 pounds. 🙁

That is a huge weight difference, do both of those wheels have the same backspacing?

 

[454GrandPrix]

Do the Monte SS wheels have the same backspace as the Z/28 wheels?

From what I am told, no. Someone else here told me the Monte SS wheels have 1/4" less backspace than what I measured on my Z28 wheels.

That is a huge weight difference

Tell me about it! I was not expecting such a huge weight increase, but I'll have to live with it. Perhaps someday I'll have $500+ to drop on a set of lightweight aftermarket wheels that fit... but today is not that day.

do both of those wheels have the same backspacing?

No, the T-Type wheel has 1/4" less backspace than my Z28 wheel. My measurements to the outside of the rear rim are 4.25" on the Z28 wheel and 4.0" on the T-Type wheel. I think the "official" way to measure backspace is to the inside of the rear rim lip, which would instead give you figures of 4.0" and 3.75" respectively. (I measured to the outside of the rim lip because I had to measure the Z28 wheel with the tire still mounted.)

I have read that the Vector-style T-Type wheels have 3.75" of backspace, and I'm betting that is measured to the inside of the rear lip. Of course, I have no idea how the back of the spoke area looks on those wheels, so I have no idea if they would have fit over my Blazer brake calipers.

 

[565bbchevy]

Perhaps someday I'll have $500+ to drop on a set of lightweight aftermarket wheels that fit... but today is not that day.

Last year I bought my 15" x 8" ARE wheels used for $150 for all 4 and put them on my Regal and was surprised when I weighed them minus center caps were only a pound heavier than my Convo Pros, they are an older style but the price was right.

 

[axisg]

FWIW the blazer brakes will just fit with the stock alum Monte SS wheels. Car looks great BTW !

 

[454GrandPrix]

Updates:

#1: I got the other tires swapped over to the T-Type wheels and mounted on the car.

#2: my steering gearbox (which had been slowly leaking for quite a while) suddenly started gushing fluid. I had to keep the car parked until my ordered 800 gearbox arrived. I installed it, only to find out it screwed up my alignment. The car stayed parked until I got that done; we centered the steering box and adjusted the tie rods to make the tires line up with the gearbox, then I had to straighten the steering wheel slightly to line up with everything else. But now I have 12.7:1 ratio and no leaks, which is great.

#3: Finally back on the road, I quickly discovered one of my dust shields was rubbing the rotor. Oops. A few minutes with a small pry bar took care of that.

#4: Now I'm really on the road. I noticed my new-to-me Blazer brake upgrade consistently pulls to the left. As a reminder, I am using all the junkyard hardware--the pads, rotors and everything are exactly as I removed them from the donor car, and I didn't even disassemble them when I bolted the whole thing to my GP. So I'm guessing I need to clean and lubricate the caliper pins or something. That will be my next project.

But it feels great to finally be behind the wheel again. 🙂