Vapor Lock?

[izzy_Britton]

So my truck is acting funny. at first i thought it was the fuel pump, or maybe the tank valve under the cab or maybe even the aftermarket hei distributor. but i am thinking it is likely a vapor lock condition? i have never dealt with a vapor lock condition before so i dunno what is it like.

This happened the first time about 3 weeks ago. I went camping, pulled my 16 foot travel trailer over the hills to the coast. on the way home cruising at 50(ish) mph the truck seemed to just run out of gas. Those of you with dual tanks know, when you run out on tank 1 and the truck starts to blubber, reach over hit the switch and a few seconds later your off an running again. this is exactly what it seemed like to me. I changed tanks even though i just left the gas station about 40 miles earlier... switched tanks, and it never would pick up and take off, finally it just died. sat on the side of the road for a while fired up the truck and off i went.

40 miles later it happened again. exact same way, but it wouldnt start at all, finally called for a tow truck and he hauled me the 65 miles home. once home the truck started just fine. disconnected the trailer and been driving fine ever since.

fast forward 3 weeks, to today. driving up the freeway, towing my boat, runs out of fuel in tank 1, switch to tank 2, off we go, 5 minutes later, tank 2 is out of fuel, stab it into a fuel stop and put 20$ in it and again off i go. I make it about 1/2 mile down the road to the freeway on ramp and it starts blubbering when i get on it to merge with traffic leaving me hanging and a prime target for a big rig. i need to drive 20 miles north and then 30 miles south to home again, and the truck blubbers the whole way exactly like it does when it is out of gas and you need to change tanks.

WTF!?

it seems to only do this under a load, when towing for example, and both today and 3 weeks ago it was over 100F. is it the opinion of ye readers that this could be a vapor lock issue? how do i fix it?

86 chev edelbrock 1406 carb, napa HEI (mallory clone) distributor, all emissions removed, 700R4 in low gear when towing never over 50 today or last week except when coasting down a hill. today was flat land with only slight rise and fall in elevation, noting horrible. temp reads between 200-210.

IDEAS PLEASE? i want to go to the lake next weekend but have nothing to tow my boat to the lake with.... GRR