Oil pump standpipe lengths

The standpipe and the filter's antidrainback valve do two different jobs. The filter's ADBV stops oil draining into the path upstream of the filter; the standpipe stops oil draining into the path downstream of the filter. They work together to keep the filter full after engine shutdown. Of the two, the ADBV is more important because the upstream path (oil pump --> pickup tube --> pan) is much freer than the downstream path (bearing clearances measured in thousandths of an inch, etc).

This '62 TSB describes the first revision to the Slant-6 oil pump in this area: a standpipe in the oil filter adapter. No valve in it; that was added in '63ish. I prefer the standpipe without the valve, because it is less restrictive and it is problem-proof. The valve can keep more oil in the filter, all the way up to the top, while the plain standpipe maintains oil "only" up to the top of the pipe, but c'mon.

I've thought of making real nice new large-bore, low-restriction filter adapter/standpipes out of machined bronze or something.