The previous owner of my '89 built some first generation standard seats and put new foam and leather on them. They seem overstuffed, like I'm sitting on them rather than in them.

A couple days ago I sat in an '84 with well preserved original standard seats and I was amazed to find that I sat damn near 4" lower in them than in my car. My shoulder went from slightly below the window sill to a couple/few inches above it in my car.

I really dislike my seats. They're wobbly, I sit too high, and the bolsters suck. As they have brand new foam in them, I assume this is the best the bolsters ever were. Not very bolstery. In turns I just squish them down and roll right over them. And I'm only 5' 10" 200 lbs.

I've found through research that it's common for people to shave down their seat foam so that's what i'm going to try on the bottom cushions. As for the bolsters, though, how feasible is it to carve my own replacement pieces out of stiffer foam to make them more rigid and supportive? Any input is welcome, especially from anyone who has tried something like this.

In constrast, I have a pair of seats out of a 2nd gen Toyota Supra (or 3rd gen Celica GT-S) that I'm planning to put in my GTO and they are awesome. I owned a Celica GT-S years ago so they're like old friends and I marvel at how crappy GMs offerings are compared to these.

Finally, I'm curious if the Corvette Sport Seats were actually built better than the Standard Seats, irrespective of the additional controls. Are they structurally more solid? Do they feel way different?

 

I think the answer is more about your skill and comfort level on modifying seat foam. I successfully rebuilt my first V8 at age 13 but the last time I tried seat foam (short few years ago) I butchered it badly. Took to local shop where a very skilled man fixed my goof and accomplished my original plan with ease. But since you have other options I say go for it. Those of us who own these critters take joy and pride in saying "I did that". Good luck with your project and post some finished pics when done.

 

sport seats from 89-93 are very, very, good. personally id just find a set, and bolt them in. you will need to run power and ground to the electric bolster controls. Are you tracking or autocrossing the car?

 

Right before I flew down to California to buy my car, I was looking on FB marketplace at a set of 89-93 sport seats in black that were being offered for $300. In hindsight it's obvious that I should have bought them but at the time, it seemed rash to buy seats for a car I didn't yet own and wasn't a sure thing... Damn it!

I'm not tracking the car, though I'd like to get into autocrossing it a bit at some point. I sat in a non-sport 89-93 seat recently and wasn't terribly impressed; it felt spongy and limp and not particularly supportive, similar to what I have. Are the sport versions that much better?

It's not the geometry of the seats that's the problem. They're actually sized well for me. It's that the bolster foam is so soft and collapsible. I was looking at my Supra seats again and determined that the hardness of the foam they're made of is what makes them so effective. Chevy really dropped the ball on this aspect.

Here's an image of those Supra seats in a car for reference. They have all the adjustibility of the Corvette sport seats but done fully manually. These were being offered contemporaneously with our cars and man, they were just so much better made. Frankly, I wish Toyota had built the Corvette... I'll go to the corner and flog myself now.

 

I had the same problem with new seats. I had recovered my seats years ago and saw the foam was pretty worn then but kept them anyway. This past year I bought new mounted seats and installed them and felt the same “I’m sitting on top of the seat instead of in it” feeling.

so ok, it’s partly because the old foam was 30 years old but still didn’t feel right. I had bought new webbing kits and decided to take the two center webs out. That made a big difference. Also I noticed that the seat cushion was catching on the front corners of the plastic lower pan and not going fully down. It’s possible to clip the lower cushion in without it being fully down/in the pan.

so now after 6 months or so the seat feels “right” and I’m happy. The foam to me is pretty firm so I think it takes some time to squeeze down a little.