Well if RRR is out,
then;
>Your first pick shows some strange vacuum-line routing. But I'm not real familiar with vans. Nevertheless, that looks wonky.
The one from the manifold to the float bowl has got to go. The Float-bowl has to be vented to atmosphere, while running. This is non-negotiable.
The PCV should be running to the front of the carb and entering just below the throttle valves. Yours may have some funky routing between the two halves, making yours correct IDK, but to me, I don't like not knowing. If in fact it is sucking from the back side of the throttle plate, I can almost guarantee an off-idle sag. If the front is routed to the PB booster then for sure you're gonna have trouble.
IMO, if it was mine, I would run the PB booster to that rear nipple, and put the PCV back on the front where it belongs.
The VA at least, looks right.
>My guess is that your rear jumper hose from sender to hard line, is sucking air, and the carb is just running out of gas. If you already replaced that rear jumper, great; now double-up the screw-clamps..... unless you are using the factory original band-clamps on regular gas-line. If yur using EFI line, double-clamp it.
This line, being higher than the tank, will not leak fuel. When the pump sucks air there, it will eventually lose it's prime, the carb will dry up, and you will think you got a bad pump, but, humor me; just double-clamp both ends, actually, all ends on the suction side..
>As for the loop in the supply line at the pump;
On my car, I've been running it like that since 1999, in the same way to a mechanical pump. However, on mine, using EFI line, I had to double up the clamps, rotating them 180* to get the pump to stop sucking air. From the pump to the carb is all hard line, my filter is at the back.
Happy HotRodding
It's a van? Didn't see that- guess I should have looked closer at the pics with the frame and suspension in them! I know Lean burn started in '76- maybe trucks/vans didn't get it right away (or at all).
