Hot Rods Chassis black and undercoating

I need to paint an assembled chassis that I am in the process of steam cleaning decades of grease and oil off of. Most of the chassis black products look to be alkyd paint. Are there any that work better than others on things that are clean, but not sand blasted or sanded?

Also, since the body is up in the air, I need to renew the undercoating. It has a sprayed on asphalt I’m type product. It has held up well, but there is some missing here and there. It would be nice to spray on a similar product, but again, I don’t which one would work best. The bottom of the body will be hit with my hot water pressure washer and a few repairs made before undercoating.

Any ideas on this appreciated.

 

One of the HAMBers suggested Lubriplate Gear Shield Extra Heavy. I am testing it

 

The alkyd oil based paint is what I have always used on frames, it holds up well.

I also found a spray on undercoating I got from Orileys. HRP

 

GM #1050104 black reconditioning paint and 3M Body Shutz for undercoating.

 

I don’t understand, lubriplate gearshield is lithium grease. That is kind of the opposite of what I am doing.