JoeC> Thanks for the Great pic.!! I have never looked at that one before.
Stage I is 160 hp.
Stage II is 190 hp.
Stage III is 220 hp.
Stage IV is 240 hp. and too big of bore for D Prod. class.
That info. came from my factory Yenko Stinger Brochure.
Here is some other info. which tells a little different story on stages IV & V.
http://www.magi.com/~gaube/corvair/yenko11.html
Happy Holidays to all here. Thanks for a Great site !!
Rick