So far on here ii learned Speedmasters are a great alternative over rebuilding cast. They are aluminum and port work guys like porting aluminum its easier quicker cleaner etc.
Speedmasters for the most part people buy them and send them out to be gone over hey are not direct bolt on or expect possible issues if you do.
I attest for s tock street build on a budget rebuilt cast may work for some people who aren't racing (they worked on the street in the 70s ) and come in 2 to 300 dollars or more cheaper than speedmasters with the seemingly required machne work..just another point of view there anre always more than one point of view .
