I am guessing that the wide lca is to make the cam compatible with the O.D. and lockup/3.55 rear gear? If i read it right, the kiesler trans uses a lockup converter? That would make for a tough cam selection?
Speculating hear that the trans has a 4th gear od of .70 and a 28 inch tall tire. That would provide 1800 rpm at 60 mph. If you can go deeper rear gears, like 4.10 or 4.30 to bring the O.D. cruise rpm up to 2200 to 2400 it would allow a much faster combo. I agree on the header change. 2 inch tubes with a long collector backed by an expansion chamber and really good flowing mufflers into 3 inch.