I'm working on my 79 TA with an Olds 403.  It's got an Edelbrock
Performer RPM & a Holley 750.
It stinks to high heaven when running & there's smoke.  I think it's
white, but it's hard to tell.  I originally thought it backfired, blew
the power valve & was running too rich, but now I'm leaning towards a
coolant leak.
There aren't bubbles in the coolant when running, but it does appear
that the coolant level's dropping.
The car did sit for quite some time.  Is it possible that the seal
around the intake manifold dried up?  These things use a metal gasket
that also forms the valley pan.
Is there a sure fire, home-done way of telling if there's a coolant
leak & if so, where it's coming from?

Thanks for any help.

Chris