Sounds like you have a good find there.... There is a good possibility the engine was worked on or rebuilt before by someone knowledgeable of the 235 heads on a 261 block..... I will bet you $5 bucks the steam holes have already been drilled in the "848" head to match the block.

If you rebuild one caution.... when replacing the pistons you may find them tooo short and they will leave to much space at the TDC..... space between piston top and top of engine block.... good specs call for pistons to be recessed .020 to get the advantage of higher compression.

The solution.... which is costly time wise is to install a couple of piston on the rebuilt crank and rotate to take measurements.... then dis-assemble the whole thing.... and have the machine shop mill the top deck of the block to .020 or .030 clearance.... than clean the whole block and re-assemble...... from what I have been told and read there is very little metal that you can shave off the heads and it must be taken off the block deck......

My new found knowledge was acquired in rebuilding my 261..... according to paper calculation from the "Mawsheene" shop expurt I should come out around a conservative 9 to 1 which is a whole point better than stock..... overall a %50 percent improvement on the original 216 BHP...around 150....I hope!!!!

As I am not a real expurt but learning as I go I would appreciate comments from resident "gurus"

Bob C.

Bob C.
CMP Heaven
The Hammond Barn