The up-pipe from the factory was UNCOATED. It was a bin part, like the turbo heat shields, so nicks, scrapes, etc. were common.
here are pics of an original NOS up-pipe.
Notice the surface marks and grooves lenghwise from the bender and just the raw stock tubing used.
In 1992, I experimented with different finishes and coatings for the up-pipe. I polished a different NOS up-pipe using fine steel wool and WD40 as a medium.
This is the result.
I was happy with the polished look.
A third up-pipe, a used one, I media blasted using medium glass bead media. It cleaned up nicely but was a matte finish. So I polished that one as well. First on the bufffing wheel using a medium cut compound, then different wheels and jeweler's rouge, then the steel wool and WD-40. The end result was like the second pair of pics.
I don't like the aluminum coating spray paints. To me, it just does not look right. From the factory, only the intake manifold and doghouse were painted. Valve covers were left bare aluminum. I media blasted my valve covers and sprayed them with VHT Hi-Temp Aluminum coating. Didn't like the result, so I glass beaded them again and installed bare.
I tried an aluminum coating on the turbo heat shield. did not like that appearance seen here
So that cover was reserved for experimenting with hi-temp ceramic coatings.
I used a different, like-new turbo cover and did the same steel wool and WD-40 routine as on the polished up-pipe pictured.
In this above pic, the up-pipe installed was the forth experiment. It was media blasted and then coated with a stainless steel coating as an aerosol spray. The product was Stylene, made by Drummond American Corp., now Lawson products. I don't believe Stylene is still available.
Maybe just polishing the up-pipe will yield a good finish for you. At least, you can see what an original looked like and taylor that to your specific taste.
But today, we have powder coating and thin-film ceramic coatings to choose from.
Regarding the radiator support and radiator top plate...
To re-do the radiator support, I'd dismantle the front clip and send that large part for media blasting or chemical-based stripping, then prime and spray. Underhood black is about 80 percent gloss. Eastwood makes an underhood black or have a body shop mix and spray some samples for you. Trying to match the inner fenders may take some trial and error with the percent gloss. Certainly no rattle can off the shelf will match - but Eastwood is close, but the surrounding parts possible have a 30 years old finish.
For the radiator top plate....media blast to strip. if there are surface imperfections like small craters on the front part by the latch, it's a little more work. I would suggest powder coating this top plate. Again about 80 % gloss black. A good coater can build the powder over those surface imperfections so the result is a completely smooth surface. However, you may have to use a direct to metal primer and filler to achieve a smooth part ready for powercoating. discuss with the coater.
If you media blast, prime, and spray with Eastwood underhood black, all the surface imperfections of rust/material removed by media blasting process will just be carried through and highly visible in the finished product. have to use the appropriate filler.
