[Fred T]

I have the filter under the cab on both my trucks. No problems with vapor lock, which is usually caused by the fuel line located to close to a heat source, such as exhaust. Biggest problem with filters under the cab is leakage, which usually is just enough to drain the pump and carb when parked for a couple of days. If you're using rubber line and hose clamps, a little Hylomar sealant will fix that. Best to use compression fittings.