Posed the question a couple of weeks back and it didn't seem like anyone has gone through the trouble to find molded heater hoses that fit the LS1 in a FD chassis better than a straight hose that bends way up on the fender liner. Well, after several trips to my local auto stores I have the solution.
Gates 18078
Gates 28471and for our Canadian brothers here is a set of alternative part numbers found by
quinns in reply #47:
Dayco 87611
Dayco 80405I haven't verified the above part numbers, but I expect quinns has tried them.
The picture above doesn't actually show both of the correct hoses. I later found that 18078 was a better fit since it is a 5/8" hose that scales up to 3/4" right at the water pump nozzle. Gates 28471 is 5/8" all the way though. I've found that 5/8" is a good tight fit on the heater core barbs (may require boiling the hoses + windex) and my LS1 water pump uses a 3/4" and a 5/8" barb, thus the need for one hose to transition to 3/4"
They aren't truly "drop in" like my title says as they will require a little shortening, but it's pretty dang close and when you're finished, the routing will look factory.
Lane