[rwhite65]

depending on the year...there could be slight changes to this.....and also if it has already been rebuilt.
but generally,
The H.O. had forged pistons, low tension rings, and a roller cam, as well as a different firing order. A non - H.O., may have had roller cam previsions, but depending on the car it came out of, generally did not have the above mentioned options.

If I am off on this, someone will correct me.

In all honesty, sell the non-h.o. and use that money towards the h.o.
Ryan