Hello all. It's been awhile since I posted. Our (my son and I) Austin Healey street rod project is progressing slowly. The engine is basically done and in the chassis. We have started fitting body parts. Pictures below (hopefully). Here is our dilemma. We need to start the engine to see what kind of vacuum we're pulling so we can order an appropriate brake booster. The heads are AFR 165s which replace the original Mustang 2 302 heads. We're looking for cheap (probably one time use) exhaust manifolds so we can start it and measure vacuum. We're hoping that there are other 302 exhaust manifolds available, not necessarily from a Mustang 2 that we could find and use; Ford trucks, broncos, Explorers, etc? Does anyone have a swap / interchangeability chart or info? Thanks in advance for your help? Here's where we are at this point: