Fuel recommendations during the rising gas prices!

Hey gang!

Here's a question, with the rising gas prices, what octane would you recommend to run in gasoline with the older classic Mopars like mine, As everyone on the board knows, at least on the old site, that I have a '68 Valiant with the 273 small block engine. My mechanic says run high test over regular unleaded (I just paid $2.30 a gallon for 93 octane at the local Texaco station near where I live. Would anyone recommend using 87 octane and using some kind of octane booster to make up for the higher gas price or would the engine suffer in performance. The car seems to run excellent on high test and seems to knock a little using regular unleaded gasoline. or should I be using regular unleaded? Any information would be greatly appreciated! Thanks again for everybody's support! I look foreward to be hearing from the group soon!

Sincerely yours,

Brian T. Carotenuto