I'm very interested too! Hopefully it will be off backorder soon.
Few other parts came in, and I found a better way to actually mount the Hydramat to the sending unit. Would you believe Holley themselves actually show a 73-87 Chevy fuel tank as an example of installation? I just didn't see the exact fitting I needed, so now I have the correct one on the way.
The braided UltraPro fuel line came in! Two 10' sections WERE NOT CHEAP but should be more than enough for the truck.
AC Delco Detent/kickdown cable showed up from Summit too:
Ordered the correct outlet fitting for my fuel pump:
Aaaaaand the correct fitting for the Hydramat to the solid line shown in Holley's install example:
Also ordered a universal crossover exhaust system and header flanges from Summit, for the price and shipping with other parts I just couldn't beat it. I figured I'd give it a shot at making my own instead of paying a shop to build one. I think the only thing I'll need to outsource is the driveshaft!
And finally the new sending unit came in! I picked this one specifically for the large, blank spot in order to modify it like so for the high pressure return line:
First, mark where the hole is to be drilled:
Hole drilled and deburred:
Pass-though fitting and seal installed (UltraPro hose end shown threaded on here):
