[rghines1]

Thanks Texasrocker for the tip! This one goes into a lot of detail that I've never seen before about any necessary modifications.

While on the subject, another worth looking for that concerns direct substitutions w/o making any modifications is a Rider publication written by H. A. Middleton. Name on mine is 1963 Tube Caddy, tube substitution guidebook. It simply rates the substitutes with a good or excellent rating.

Richard