No..on a 66 the grill is not removable...Ford realized that particular mistake after a few years...no easy way to clean out the garbage(not sure how many 69+ owners did anyway though)
The funny thing is that if it were a v8 I wouldn't hesitate to pull it, but the extra length of the I6 makes me wonder how much of a pain its going to be to pull with the trans attached(no way I am pulling it without the trans...I absolutely HATE pulling an engine without a trans...you waste so much time realigning them in-car, doesnt matter if its FWD or RWD, I will pull both together 98% of the time)My engine was out but IDK if thats a requirement. It sure was nice to stand in the engine bay and work. a 6 cyl should come out easy and pretty qwik- I get not taking it out and putting it back- but I think it will be easier in the long run-
You can have the engine out in 1/2 hour. Just do it. The amount of time you'll save with it out of the way will be WAY worth your while. I did quite a bit of my cowl replacement standing in the engine bay. You'll also discover a lot of things that need to be addressed in the bay while the engine is out making it much easier when it comes time to make the change over to V8.Is cowl replacement with the engine in place feasible? I can always jack the engine up from below to take the majority of the weight off the shock towers if need be. It would certainly be more convenient to be able to move around in the engine bay...but being a tall guy I dont have any trouble reaching across the cowl as needed for spot weld access.
I am curious as to why you think plug welding is inferior to spot welding? The weld is the same regardless, as long as the two pieces are pressed together tightly through whatever method...the metal around the weld will fail long before the weld itself...spot welded or plug welded(although I have noticed a few factory plug welds that are failing...but they weren't correctly plug welded to start with(half the hole or more wasn't even filled)I'd do at least the bottom... I'd do the top as well because it doesn't cost much more than doing only the bottom, and it can be done using the original "spot weld" method. If you replace the bottom only, you'll be filling the holes you drilled in the top rather than a true spot weld. The cowl is structural. Do it once, do it right.
I didn't have the option of "either/or" on my 69. There's no patch kit available and the only cowl replacement was top and bottom, and I'm glad it was the only option.
I welded the bottom in, primed it and painted it, but masked off the lip so I'd get a clean weld when I did the top. Granted, Ford didn't paint the lower cowl, but you can't see it once the top is on.
Heck, you've got it apart anyway, and Dynacorn does a really nice job with the repro parts. Might as well do the whole thing.
So...just for general amusement...the firewall flange where the alignment holes were was rotted away:I would definitely take the time to epoxy prime everything as you are going. From the firewall, under the cowl and the inside (top and bottom) since you are in there. I actually put a single stage urethane on the inside of my '70's cowl over the epoxy when I replaced it. There are several alignment holes in the cowl to assist you in getting it lined back up. I strongly suggest using an export brace to check the firewall positioning before welding the lower in place. Fit everything before committing to welding. If something needs to be adjusted, do it during the fit-up process. I remove the paint from each rosette weld hole with a small wire bush once everything is primed and sheet metal screwed in place. I've installed a couple of these, it really isn't that bad. Pay attention to the details and it will come out nice.
Do you have any holes punched to weld at the lower windshield lip?