I'm gonna guess you have a breather on one of your valve covers, and when in boost your pushing some pressure past valve seals and out through the breather. Kinda normal if you ask me if your heads have never been redone.
If I had to guess it's smoke from blow by or you have an oil leaking onto the exhaust manifold.. You can do a simple test for blow by, by removing your oil fill with the engine running. If you feel air pushing out, you will need to start saving up for an engine.
If its coming out of the breather its 99.9% blow by. The rings or pistons are bad and the engine needs a rebuild.
I . Just finished rebuilding my Type T. ...
What the heck is a "Type T"?? 86=T-type 87=Turbo T