You might want to look at a 69-70 Mustang to see how theirs is made.  They are bolt-on.

Derek wrote:

I thought long and hard about doing this to mine as well. But the reality became clear that it wasn't nessessary. These cars lived for at least 20+ years as daily drivers before the cowls rotted out. And that was with little or no paint inside the cowls. These cars lives are different now, the only time they get wet is when you wash them. I ended up just replacing the upper and lower cowl with stock peices, but just OVER did it this time. Weld through primer on the flanges , couple heavy coats of paint everywere else. Then I rolled on ah thin layer of roofing tar on the flange so when the two went together they were sealed from the inside. Then I also ran ah line of strip caulk around the inner perimiter to keep water and debris out of the seam. Thennn when I was done ,I touched it up with internal frame sealer. This is WAY OVER KILL, but it should NEVER need another cowl!!!!!!

WOW....you are going to weld that cowl with the flamable cement...oooh fire...fire....jj 

DAMMM nice  Now that your done practicing come on over and do my cowl  

Nice job Derek!

Here's what I was thinking: I removed the upper cowl and replaced the cowl areas with patch panels about 13 years ago. I coated the underside of the cover and lower cowl with POR-15, then ran a bead of silicone sealer along the edge similar to how you did. Then I painted over the POR-15 with rattle can paint approx the color I wanted to have the car painted. I used weld-through primer on the flanges, and welded it back on. There are a couple of problems with this that I found out much later: 

1) Turns out the silicone while well intended, has crappy adhesion and peels off relatively easily. 
2) I lap welded the patches, and I'm not entirely confident in my welding skills back then. 
3) The spray can paint doesn't adhere well to the POR-15. 
4) The POR-15 doesn't always adhere to the metal well over time, even using that metal-ready spray.
5) I painted the POR-15 right over some of the old paint in the center section of the lower cowl, again, adhesion woes.
6) I layed down plastic bags on the inside of the cowl to prevent debris from getting in when grinding welds and a small piece accidentally got pinched between the cowl flange in an inaccessible area and melted from the welding, and I can't get it out.

Now I've decided I am going to have the car acid dipped at a resto shop in Oregon, and they've said they'll be able to get to the inside most of the cowl with epoxy and a wand, which fixes some of the above problems. But making it somehow removable would give me a lot more peace of mind. That ensures complete coverage when painting and makes it possible to get the crap out of it if it's parked under a tree or something. That way I don't have to worry as much about weather as well. It's probably overkill, but it would be the ultimate cowl solution.

Jieve wrote:

Nice job Derek!

Here's what I was thinking: I removed the upper cowl and replaced the cowl areas with patch panels about 13 years ago. I coated the underside of the cover and lower cowl with POR-15, then ran a bead of silicone sealer along the edge similar to how you did. Then I painted over the POR-15 with rattle can paint approx the color I wanted to have the car painted. I used weld-through primer on the flanges, and welded it back on. There are a couple of problems with this that I found out much later: 

1) Turns out the silicone while well intended, has crappy adhesion and peels off relatively easily. 
2) I lap welded the patches, and I'm not entirely confident in my welding skills back then. 
3) The spray can paint doesn't adhere well to the POR-15. 
4) The POR-15 doesn't always adhere to the metal well over time, even using that metal-ready spray.
5) I painted the POR-15 right over some of the old paint in the center section of the lower cowl, again, adhesion woes.
6) I layed down plastic bags on the inside of the cowl to prevent debris from getting in when grinding welds and a small piece accidentally got pinched between the cowl flange in an inaccessible area and melted from the welding, and I can't get it out.

Now I've decided I am going to have the car acid dipped at a resto shop in Oregon, and they've said they'll be able to get to the inside most of the cowl with epoxy and a wand, which fixes some of the above problems. But making it somehow removable would give me a lot more peace of mind. That ensures complete coverage when painting and makes it possible to get the crap out of it if it's parked under a tree or something. That way I don't have to worry as much about weather as well. It's probably overkill, but it would be the ultimate cowl solution.

Yeah I tried the POR15 thing as well and ended up strippin it all back off. In my opinion its just way too picky about what it wants to stick to. I was able to peel most of it off with ah blow gun if that tells you anything As for repainting yours I'd recommend useing this stuff from eastwoodIt comes with about ah 24" hose with a nozzle on the end that you can stick ANYWEAR you need it to go. The nozzle sprays ah 360 degree pattern inside your work. It took 2 cans to do the cowl