As stated above, the 235 full-pressure engine ('54-'62) has to be converted to a full-flow oil system before you can convert to a spin-on filter.
Check out the Tech Tips, Full Flow Conversion article on the Inliners site:
http://www.inliners.org/ The 1958-1962 261 (Chevy truck) engine was a full-pressure, full-flow engine. It is ready for conversion from the (tall) canister oil filter to a spin-on oil filter. In would be interesting to hear from someone who has done this conversion.
A spin-on filter conversion kit can be purchased for about $25 (complete with fittings, lines, and filter head but no filter). This is easy to mount on the firewall (this is what I have done with my 1960 261) or low on the block (within the last month there was a posting in this forum with pictures - on a 261, as I recall).
Tim
