New rebuild has odd vapors?

Capt46 said

Definitely a must at this point......:thumbsup:
Did you run engine long enough for thermostat to open? If test was conducted for 10 min and held 16 lbs then dropped to 15lbs after 15 min engine off but warm how much time did you give to warm engine. just trying to think this out....

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Hmmm...I did not run fully up to temp. Wasn't sure I needed to do that. That could be done tomorrow.
Manual brakes...no booster.
I'm starting to get concerned about the possibility of a crack in the head. Don't know if heads where magnafluxed.
I do have a set of rebuilt 302's, but don't know true condition either .(same builder) . Also have original heads from engine.
I'd like to fully test everything before going the route of swapping heads.
Appreciate everyones input! TY.