I have 31 Dave's small-body HEI conversions, from his MSD trigger only, regular HEI for carburetted engines, and his new ones, EFI-HEI feedback for EFI systems. ALL use the module OUTSIDE the body, NONE have ever had weather issues. One of the systems is on one of my I/H Travel-All's, and it runs in the mud and snow all the time in winter, never had an issue with his stuff. He is now doing one for my 32nd project, 1965 Pontiac GTO, 455, 4 speed, with tri-power.
I used to use a lot of other systems on my project vehicles, with mediocre to bad results. Now, when I get a new project to do, as I now have waiting in the driveway, project number 33, I don't even go for the other systems, except for an MSD box if that project gets one (and, then, Dave gets the distributor for it for one of his MSD trigger only conversions). I just remove the distributor, and, send it to Dave, along with one of his specification sheets. It comes back right, the first time, with no hassles, no problems.
His web site is - davessmallbodyheis.com - His e/mail is - [email protected]