[Cunningr]

For autocross you don't need so much HP.

I went to the engine builder website and their rebuilds come with a 12 month 12K mile warranty.

Since your soliciting opinions, unless you can get away with just replacing the heads any other way you go you will have too much invested to break even. With everything else in such great shape would be a shame to do a V8 conversion or sell it off for a strip down.

Tough spot, Good luck on your decision.