About a year ago my wife noticed that the '66 Strato buckets in the Starfire had no seat back locks and would fold up on us in an accident. For the past 20 years, I had my '66 original seats with redone foam sitting on '82 Camaro 6 way seat mechanisms which are much shorter profile than '60's era 6 way seat mechanisms. The idea was to add seat back locks and headrests while we're at it. I figured swapping 69's for 66's would be pretty much a bolt on, but it wasn't. Here's the story:

GM Strato buckets, as a basic design were installed in A Bodies, (Cutlass, Skylark, Chevelle, etc), a few B bodies (Like my Starfire) and maybe a few C bodies like the Pontiac 2+2. The reproduction/replacment market is pretty healthy for these parts. Lots of sources and reasonable prices. ​​​​​​​As far as I can tell GM never put 6 way mechanisms under Strato buckets, only 4 way tracks. The 4 way tracks are now rare and expensive.

Here's an out of the car shot:

69 Chevelle Strato Bucket in Olds '66 Starfire trim

In '67 GM Strato Buckets got side-button seat back locks. In '69 they got the center button locks on the back of the seat. The designs look similar but the frames are different from one another for each of these generations. The big difference among the generations of seats is the location of the locking mechanism and lock buttons. It means you can't easily graft a 67 back on to a '66 seat bottom, nor a '69 back onto a '67 seat bottom. You have to get a working set. I tried to find a set of '67's, but couldn't find the locking rod that connects the side button to the seat bottom lock. So I went with OPGI's Chevelle seats from a 69 - frames, foam, trim, everything but the vinyl. I had the covers made locally to match what was in the car. Since no one makes kits for a '66 Starfire...

When I got the seats back from upholstery, they sat 2-3" too high with fresh springs & foam. my 5'10" head almost hit the headliner. Not comfortable, not safe. The springs & foam will settle down, but not 3".

I had to figure out a way to get the seats to sit lower in the car. 2 choices: cut channels into the floors or reduce the height of the seat bottoms. I checked with a local fabricator on cutting floors, but he recommended against it. Wisely. So I took a look at my old seats to see if the sitting height could be reduced. I settled on grinding out selected parts of the seat bottom with an angle grinder to make slots which allow the seat tracks to sit higher in the seat.

Since I'm new at angle grinding, I practiced on my old seats before cutting into expensive replacements. About a week ago I got advice from you all on the Metabo angle grinder. Great advice, thank you.

I wound up modifying the front of the seat undersides and left the rears alone, though if you're taller than me, you might want to lower the rear seat mounts too.

Here are some shots of what I removed. This my angle grinder "practice" old driver's seat as viewed from the side:

Modifying a strato bucket to lower sitting height. Removing carefully selected sections of steel and avoid weakening spot welds.

Here's a top shot:

The idea is to remove parts of 1 of the two layer seat construction while not compromising strength. Then bolt the seat tracks to the vertically higher remaining layer.

It turned out I didn't get quite enough height out of the seat, so I took out a couple of layers of insulation from the floor under the seat tracks to get them to sit as low as possible against the floor. Goodbye under carpet jute, goodbye dynamat, hello 7/16"s mounting bolts and a 1.5" spacer under the outside rears.

Here's a shot of of the Camaro seat track in the Starfire. It's much lower profile than 60's 6 way seat tracks. The trick here is to get the front mounts to sit as low as possible. The other thing to watch is to get the seat level side to side. Ultimately I was limited on the seat angle by the shape of the inside of the Starfire floor. The outside track has enough clearance that it's not a limation.

82 Camaro 6 way seat tracks in '66 Starfire.

Here's a side view of the seat tracks. You can see the track contours fore & aft which increase seat height:

Front bumps need slots in the seat bottoms to minimize height. Outer track needs custom holes in tracks & seat bottom.

The Starfire floor has 2 different angles front/rear for inside and outside seat tracks. The inside one is much shallower and limits how much angle you can get out:

Outside rear mounts need spacers since they sit very low. Inside track front sits high and limits how low you can get the seat.

It took about 3 days for me to get all these cuts and fitting done. Lots of test fitting, hogging out holes, cutting carefully to be sure not to destroy too many welds. In the end I'm happy, but I might one day lower the seat rears too. Along the way I notched some of the plastic trim too, but it may have been unneccesary.

Here's the final result. Looks factory enough for me:

6 way seats in a '66 Starfire. Fun & adjustable.




New for 2020, now with Safety Locks.

Hope you all enjoyed this. I'm no expert, but maybe this helps some of you along the way.

cheers
Chris