In the hopes this might be a help I wanted to share a readily available paint that comes pretty close and looks good with the existing colour.
Everything I take off the engine I refinish before reinstalling. For the obvious reasons; inspection, cleaning, corrosion etc.
Many years of restoring vintage motorcycles has forced me to perfect spray paint application. I have no choice for some secondary pieces and would never use this for principle parts like frames, tanks, fenders etc. Those go off to the pros. Sorry back to our boat engines.
If you'd like superior spray paint results than I humbly submit,this is how;
1) For everything (high heat or not) I use high temp paint such as VHT. The paint I found and like for the M35B is VHT CSP 403 Titanium Silver Blue.
2) Strip the part to bare metal. Chemical strippers, bead blasters, and 8" brass wire wheel on a bench grinder work wonders. Bare metal no less!
3) Sterilize the part. Dry it and make sure its at room temperature, not cold.
4) Before painting use Pro Form Products - Final Wipe (this alone will amp up your painting project to a far higher level) Have CLEAN latex gloves on for this and once wiped do not touch with bare fingers. Even the cleanest hands leave surface oils.
5) Paint indoors if possible but if outside, bring it inside after application to room temp.
6) Hang the piece on rigid wire if heavy and thin stainless etc if a light piece. Minimum contact area (i.e. a bolt hole etc) and such that you can rotate while applying the paint.
7) Use VHT primer (grey for this application as its a closer colour to the colour coat) apply 2 coats, 15 minutes apart, first one light (coloured but not necessarily opaque), second one medium and fully covered and coloured. ** Shake the can minimum 1 minute and between coats, between pieces if more than one. More shake, the better! Cant emphasize this enough.
Hang it to dry in a warm clean room. I often put a small heater with fan on these to expedite the cure. Wait overnight and ideally 24 hours.9) Next day. You could sand with 1000 grit but for our engine parts this can be passed. If you do then wipe dust off and use a very light quick wipe with the Final Wipe. Don't over do this or your primer will come off! As before handle the part if needed with new and very clean latex gloves or simply use the hanger wire its already on and don't touch the surface at all if not sanding.
VHT colour coats. Shake and more shake. Spray your poly or cardboard to insure an even flow. Experiment with distance from surface. This being a metallic paint it will run easily so experiment off the part with too close (probably 6") as it will run or too far (more than 12") too far makes the paint job grainy.
2 coats minimum, 15 minutes apart. As before light first, medium second. If you see a spot you don't like its better to wait another 15 and apply another coat than to keep on spraying. Sure fire way to get runs.
10) Hand it again in your warm clean room, fan or heater if no dust present and wait 24 hours.
11) Day 3. Use 2 coats VHT clear coat. Same application process as before.
12) Hang after clear coats in the warm clean room. Give it the heat / fan and leave it for as long as you can given your project. Minimum 24 hours. The paint will not be fully cured so handle and install gently. As you know, invert the can and spray until you see clear. I like to wipe the nozzle opening with a bit of solvent. This insures the next time used is as consistent a spray pattern as the first.
Spray can paint slowly cures to hard over several days but it is by no means the chemical and curing paint the pros spray.
That being said, you can get excellent results for secondary pieces and other projects (but not your vintage Cadillac)
Happy painting.