[BAMiller]

Has anyone used the stage 2.5 2-inch lowering kit from UMI for a second gen F body? I am looking at it for a 1978 Trans am build I'm starting. Any input would be appreciated.

[JLMounce]

I don't have any direct experience with that specific kit. UMI does build a good product, but it is focused more towards on-track performance. As a result, it will tend to be pretty aggressive and may be harsher than what you might want for a street car.

You didn't provide any goals on what you're after, so that may or may not fit the bill.

How much power is the car going to have? What is the intended usage? Are you more concerned with cornering performance, or ride quality? How important is the stance to you?

All of these dictate different directions. As an example, these cars with factory style, but upgraded parts like springs and traditional leaf springs can get very low, but the car stops working from a performance and ride quality standpoint. If the intent is to stay with a somewhat traditional setup, if you want the car to work well, you may have to sacrifice on stance. Or you can get the car to work and have a really nice stance, but ride quality will typically suffer.

If you want it all, you're talking about modified or aftermarket subframe in the front and an aftermarket suspension system like a 4 link or torque arm in the rear. Costs grow quite a bit here.

[BAMiller]

Planning a 461 cubic inch Pontiac 400 stroker build est 500 HP. 4l80E transmission. planning on running 17 wheels with 40 series tires. The main reason I want the tubular control arms is for the increased caster to keep it from wandering on the highway. Will be a streetcar 99% of the time. May try autocross a few times and a few trips down the dragstrip. The 2-inch drop looks better with the low-profile tires. I want a car a little more comfortable to drive to long distance car shows than my 1969 Camaro convertible. The wind noise and cowl shake can get old also it does not have A/C.

[VCho455]

I would call and talk to Dave at PTFB (Pro-touring F-body )before making a purchase. Quality products for a good price. Lots of folks say good things about his products.

https://www.pro-touringf-body.com/

[JLMounce]

Originally Posted by BAMiller

Planning a 461 cubic inch Pontiac 400 stroker build est 500 HP. 4l80E transmission. planning on running 17 wheels with 40 series tires. The main reason I want the tubular control arms is for the increased caster to keep it from wandering on the highway. Will be a streetcar 99% of the time. May try autocross a few times and a few trips down the dragstrip. The 2-inch drop looks better with the low-profile tires. I want a car a little more comfortable to drive to long distance car shows than my 1969 Camaro convertible. The wind noise and cowl shake can get old also it does not have A/C.

Talk with UMI directly if that's what you're currently looking at, but based on your response here, I think their product might be a bit more aggressive than you really want.

As mentioned above, also give PTFB a call on their stuff as well.

The RideTech Street Grip kit is a possibility, but they don't typically recommend the composite leaf springs over 400hp. Best ride in a leaf application, but they can't handle the power of a steel multi-leaf.

My advise on the wheels is to upsize to an 18" wheel. Tires for 17" wheels are starting to become scarce and expensive. The cost difference between the 17 and 18" wheels of the same design and manufacturer is typically around $150-300.00 You'll save that in tires for the 18" wheel.

[BAMiller]

Thanks for the replies, I will check out PTFB and call UMI. I am ok with a stiffer ride than stock, but I don't want it to ride like a buck board either.

[JLMounce]

The Hotchkis stuff rides nice, I can vouch for that directly. I had their 3" drop leafs and 2" drop springs in my 69 Firebird for a decade. Good ride and handling. They come in at a progressive rate between 150-175 lbs in the rear for the first gens. They will be similar for a second gen, possibly a bit heavier since the 2nd gen weighs more.

[rohrt]

I will throw in my $0.02.
If this was a 1st Gen, I didn't like the Hotchkis front springs on mine at all. Way to rough for my liking. The springs didn't give at all. I believe I used big block springs as they don't have an in between rates for Pontiacs.. I ended up changing my front springs to the Ridetech streetgrip springs. Its still plenty stiff but doesn't shake the filling out of my teeth. I also changed out the 1.25 Addco sway bar with the Ridetch sway bar. The shocks were all from Hotchkiss as well. Very light valving. I can't recall what they called them at the time.

The rear leafs are from Hotkiss, I do like them. The ridetch streetgrips are fiberglass. I'm just not that confident in using a fiberglass leaf spring.

Now you mentioned your car is a 2nd gen. This is just my opinion but my brother had a 78 Gold edition WS6 Special Performance Package that I drove quite a bit. I felt it was one of the best suspension compromises for a street car. IMO I would setup my car with the stock WS6 components (and if you wanted to take it to the next level I would look at Pollygraphite bushings, solid subframe bushing and sub frame connectors and l7" low profile tires.

[73ta]

PTFB system on my 73 TA. 570HP. Comp suspension.

[65madgoat]

Good luck getting a hold of anyone at PTFB on the phone....

[76TA462]

For my second gen (1976 Trans Am) for the front I used the UMI Upper Control Arms UPI-2653-B, UMI Lower Control Arms UPI-2651-B, UMI Coil-overs A225-550R (they were Viking Warrior double adjustable) and some misc. like bolts, spanners etc. Not sure if this applies to the 78 TA but the 76 version used half inch bolts for the upper and 14 mm for the lower bolts. For the rear I used HSS-2409C - Hotchkis rear leaf springs (lowering 1.5 inches) and the matching HSS-71020014 - Hotchkis rear shock absorbers (at the time Fox. Maybe still? I did this in 2017). And the HSS-4013 - Hotchkis frame connectors. I found it a tad too low for my liking, so I raised the rear just shy of 3 / 4 inch. Still extremely lower than my OEM set-up. The stance is awesome but did take some getting used to at the beginning. The ride is stiffer than OEM but was expected and was the reason I did this. But the ride is comfortable enough. Using 18-inch wheels with 40 profile on the rear (285 40 18) and 45 profile on the front (255 45 18). It handles better than I expected. Cornering is killer, straight and everything. But it is a 50 year old designed car. If I was to do it again, UMI had another set of control arms that were more adjustable than the set I have. For me the ones I have are more than enough, but for people who would do some tracking the added adjustment would be better. I would have done it just to have the option since I was going through the effort anyway. Kind of off topic now. I checked into upgrading the steering at the same time and did not need to for my street application. I received great advice from Power Steering. They mentioned that for my car they felt that I might not need their fast ratio 12.7:1 upgrade, because it only provides a bit more responsiveness at center than the variable 16:13 that I have in. By coincidence your year TA was mentioned - in 1978 they went to a 14:1 constant ratio gear in the Trans Ams. Good luck, the effort is well worth it if you are chasing handling.

[76TA462]

Oops. Fronts are 245 45 18.

[73ta]

Originally Posted by 65madgoat

Good luck getting a hold of anyone at PTFB on the phone....

I get him every time I call. Called him twice in the past couple of weeks.

[Skip Fix]

I have some of Dave older A arms new in box , not sure what "generation" the lowers are I went a different direction on if you are interested.
In 78 "standard" TAs had the variable ratio just the WS6 cars got the straight ratio boxes.

[pontiacstogo]

Originally Posted by BAMiller

Thanks for the replies, I will check out PTFB and call UMI. I am ok with a stiffer ride than stock, but I don't want it to ride like a buck board either.

When I was looking for some suspension items for my 4th gen Camaro UMI suggested I stop in for a visit (I was living in Altoona, PA at the time). They gave me a tour and showed me some of the vehicles they were working on. They were great to deal with and it was good to get some advice in person. Might be an option for you given your location?