sharp cutoff pentodes

[Manic]

Hi, I was wondering if anyone has any experience with any of these sharp cut off pentodes....

5672
5654
6688
6136

I believe the 6136 may be the most common, and I found a post here about them.

I found these at a local shop. I would be interested in using these in place of an EF86, if possible.

Any thoughts ?

Thnx, C. Smith