I am starting to fabricate a steel room for a friends 914GT project. I have worked out the F-R structure. It will be slightly different than the typical 5 rib structure in other examples. I will use a 3 rib structure (L, C and R) with an X brace connecting them on each side. The driver is tall and needs the head room so I have to eliminate two of the ribs for clearance.

I have worked out a scheme to attach the factory side seals.

The roof skin has been rolled on an english wheel and sits nicely on top of a factory top.

The question I Have is how to finish the rear underside trailing edge as well as how much overhang to have. I would love any pictures of this area. The current plan is to make a filler piece that sits on top of the roll bar structure and leave the rear trim like the factory GT. What about the leading edge inside the car? Should that be closed in as well?

Chris Foley has built these...still has one sitting in his shop (for like 50-years now)...

Tony

aka Tangerine Racking

here's the back of the Steel Top I had (it used a 944 Roof)

Click to view attachment

If it's a fixed steel roof I'd incorporate a 3rd brake light into the build.

I add a little filler piece at the edge so the gutter line is flat.
Click to view attachment

Rear filler piece is flanged inward to spot weld onto the targa bar and flanged outward to support and weld the rear edge of the skin.
A similarly shaped piece at the front closes off the space between the targa bar and roof skin.
Click to view attachment

Vertical portion of the rear piece is flush with the rear edge of targa structure.
Click to view attachment

Rubber welting hides the seam. The stock bright strip secures the welting.
Click to view attachment

Definitely incorporate a third brake light into the build. It's pretty much a requirement to survive in today's traffic.

Great idea!

That is so cool.. I really had not considered making one for my car until just now.. Hmm decision decision s

Chris, Thank you for the excellent pictures. They show exactly what I needed to see. I had a similar idea for the leading edge section.

This is a great topic.
The detail photos answer a lot of questions.
Thanks for posting Chris.

Take lots of pic's.

I needed somewhere to set my hood...

It's interesting to note the hood skin has a shape that could work as the start of a roof skin - if you felt like sacrificing a hood. I don't, just thought it was interesting.

I've been noodling on this a bit more and think I may have a go at doing the framing in steel then bonding on a carbon fiber skin.

It makes a lot more sense when you think about where the roof panel gets stored when it isn't on top of the car...

--DD

I’ve thought about a steel subframe and then bond in the stock top.

How about fabricating wide mounting surfaces at the top of the windshield and above the roll bar and using modern body repair adhesive to glue the original fiberglass roof on ?

I didn't see Marks response until after I posted essentially the same idea.

I think it's all about how you want the finished product to look.

I prefer a black roof, regardless of the body color. I'm not after a true 916 look.

I kinda want to do a stealth version:
- steel frame
- skinned with something shaped like the standard top - including the "rain gutter" impressions down the side
- painted black (I may even stipple it so it looks like a stock roof) with the front of the windshield header painted body color

I already have a smoothed roof that I can use to pull a mold for the carbon skin.

But knowing how I work, I'll have to get into it before I know for sure.