Looks like your straps might be too tight. Or, do you have the tank vented very well? If the vent is clogged up then the fuel pump might make it colapse.
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'69 CST Short fleetside
Lowered, 400 small block, 700R4, 4 wheel disc brakes, front & rear sway bars
See my truck at:
http://www.geocities.com/low69cst/
Student at the University of Kentucky.
Feel free to message me on AOL, SN- SS95ZQ8
My Dad's projects:
72 Short Fleet 4x4 Chyenne Super
72 Long Fleet 4x4 Chyenne Super
Both 350 autos restored original