vacum timing help. 61 caddy

I need to know how to set timing by a vacum gage? I read where with the new gas you cant set timming by light. True or Not? I just got a 1961 caddy and it is running rich and diesels on shut down. I has a miss as well. Atomised Oil is in the engine compartment.

Too high an idle, poor gas quality, advanced timing all can cause dieseling. Set the timing to spec, that is the proper technique, remember this engine requires premium fuel, it has 10.5:1 compression. Can't help with the miss, wire /plugsor compression, the oil mist can be blowby, or a cloggedcrankcase draft system.

What I have is a 1961 Cadillac with a 390 in it. Stock and 116,000 miles on it. Do you say I should be running premium it? I just bought it and the other owner said regulaor..

Well, if the old owner ran regular, it would have run poorly for him........ maybe that's why he sold it! :)

Or he may have thought that telling you "premium would have discouraged you from buying it.

Definitely use premium. Use the highest octane you can find. If possible go for the 93 octane, not the more-common 91 octane premium.