underbody paint

[Burdar]

The Challenger was completely sprayed body color on the underside.  Wrong for a restoration I know, but it was the decision I made at the time.  On the latest project I don't want a body colored underside but I don't need the factory oversprayed look either.  I'm thinking about having the bottom sprayed in a single stage medium gray.  Something that represents the factory dip primer but that is an actual top coat...not just left in primer.  It could be left gloss I think too.(still thinking that one over) 

The issue with doing that is what to do with the front frame rails.  The engine compartment can be body color up to the front side of the trans tunnel pinch weld.  Then everything back can be gray.  The front rails though run past the pinch weld to the torsion bar x-member.  What do you do there?  Run the body color all the way back to the torsion bar x-member just on the rails or do something else?  Has anyone done this before?

I think some of the Trans Am cars from back in the day used a gray paint on the bottom and interior.  They probably had the engine compartment painted gray too so those won't be of much help I don't think.

I know some members have sprayed a bed liner coating on the underside of their cars but that's something I don't want to do in this case.

Just spitballing ideas at this point I guess.  Looking for any pictures you might want to share.

[Cuda_mark]

This is how mine was done. Grey paint and clearcoat to match the factory primer and then over-sprayed + clearcoat. You can see where they stopped the color on the rails.

[76orangewagon]

PPG actually makes a Grey/Green primer (The can actually says Grey/Green Primer) that is as close as your going to get to the Dip tank color used back in the day. That's what was sprayed on the bottom of mine before the overspray Ev2 was applied.

[Burdar]

This isn't a stock restoration.  I don't want the overspray look.  However, I do like the clean look of the gray underside.  How to paint the front frame rails once you get past the trans tunnel pinch weld is the question.  I thought maybe someone had done what I'm thinking about.  Paint the underside gray and paint the rails body color all the way to the torsion bar x-member...but keep the floor gray with no overspray.  Not sure what this would look like. 

[Burdar]

It's already in primer.(epoxy?)  I just wanted something more durable then primer on the bottom.  When you touch it now with dirty hands, the dirt soaks into the pores and it doesn't wipe off.  That's why I thought just a single stage gray paint.

[autoxcuda]

They make a "hot rod" grey flat single stage paint.

Like the paint used for black painted flat stripes like on a 1970 Mach 1 but just grey.

My friends two Hemi Super Stock tribute cars are painted to look like primer, but are actually paint.

[torredcuda]

My `70 road runner will have the gray primer /overspray look but to keep the primer looking good I`ll probably spray a matte clear over it similar to cuda_mark. I get you want a cleaner look but since there is no break on the frame rail I`m not sure how it would look painted color all the way to the torsion bar crossmember. 

[70 Top Banana]

You can take the PPG grey/green primer and do a spray out. Then have the paint guys mix it in a flat paint. Then spray the underside before you lay the exterior color

[Challenger in NC]

PPG actually makes a Grey/Green primer (The can actually says Grey/Green Primer) that is as close as your going to get to the Dip tank color used back in the day. That's what was sprayed on the bottom of mine before the overspray Ev2 was applied.

Anyone know what the code/part# for this PPG primer is?