I purchased a completed build, third owner, without any of the build logs or details (originally finished 10 years ago). It’s a beautiful build from the engine to the body.

According to FFR, the engine was not purchased through them, but has mounts for 302/351.
The seller states it is a blueprinted 347, but noted he does not know if it was BluePrint the brand or just more generically a “blueprinted” build.

The only identifying characteristics I can find is Dart Pro 1 on the head.
Is there anyway I can better identify the engine and where it may have came from?

Lastly, if I can’t ID it exactly, what should I use for oil (assuming it is a 347)?