My first vehicle! 1956 CJ5

[bmorgil]

As gm is alluding to, the 134's have very little oil pressure at idle. The cam is supported by only one bearing in the front. This causes a substantial loss of oil pressure as the block and cam clearance is large where the cam is not running in bearings on the remaining cam journals. As the block and cam wears it gets worse. On a rebuild it is not uncommon to have no oil pressure at idle because the block is too worn. This is easily remedied by installing cam bearings in the remaining journals on the block. This brings the idle oil pressure up substantially.

gm has given you the "hot tip". When the oil is hot and thin bring the idle up till you see some oil pressure.