For an actual primer, or for a finish coat for something like a rat rod or beater? I have a big can of "red" primer, but I forget what kind it is. Might be Rustoleum. I'll try to remember next time I dive into the Snakepit. For a ratty rod finish, I like Model Master Rust, cut with lacquer thinner and airbrushed.
Since you seem to be building a fantasy car from an alternative reality, don't get hung up on accuracy or details. Do it whatever way you want, as nobody can really say you're "wrong." Maybe Corvettes were made out of steel on your planet! And so forth. Just have fun with it.
I built that kit and the only thing I didn't like about it is, the grille appears much too shallow. I meant to order a couple repro MPC grilles from Modelhaus and forgot it on my last order until seconds after I hit SEND. I immediately got back on and the website was closed. Ah shucks oh well. Meanwhile, you guys are killin' me with that '69 Chevelle. I WANT one of those Fathom Green ones to go with my Fathom Green '69 Camaro! Where do I get one? All I can find is the orange ones on the First Gear site. For net shopping I usually get my diecasts from diecastmodelwholesale, but they're not showing it (and I'm about to order that Supernatural '67 Chevy from them anyway). Any ideas where I could get both of those from the same place? (I hate paying shipping charges.)
Different strokes for different folks. That Barris custom above doesn't do a thing for me, except perhaps its color. I will say that it's one of the better looking things of this kind that I've seen. Many/most "customs" of this era make me shudder with their ugliness. This one doesn't.
To my eye, the First Gear Chevelle looks much better than the Danbury Mint. DM really screwed up the roof/window silhouette, same as Testor did with that cheap diecast kit they were peddling a decade ago. I ended up Dremeling and filing the window openings to a more accurate shape, at which point I had a (barely) acceptable '68 Chevelle to put on my shelf.
I didn't notice until last night that the vent windows are part of the windshield, and thus stay with the body when the doors are opened! I might cut those loose and attach them to the doors. BTW, I did a little test last night and the Walmart nail polish remover will take off the silver tampo without bothering the red paint, no problem. The more I look at and play with the thing, the more I like it.
I emailed Modelhaus to give them my updated credit card info. Got a nice response from Carol saying that they'd contact me about that closer to actual shipping time. I was among the last orders in (possibly THE last--July 6 2016) and she said they were hoping to have my stuff out "next spring" (2018). That's okay, not like I don't have six or eight dozen other projects to keep me busy till then!