Last weekend I driving around some trails and went up a long steep hill and as soon as I got to the top it started running really rough. I had been driving around all day on the freeway and out on some back roads and as soon as I did this it ran rough. I was running at high RPM's but nothing extreme. We checked the valves and nothing was out of adjustment. I played with the timing and that did nothing. I took apart the carb (Edelbrock Performer 500cfm) and checked for any junk in the carb and found nothing. I put on an electronic fuel pump tonight and a new fuel filter and that didn't change anything either. We also checked the spark plugs and the gaps are correct (.035) and they are all clean. The heads are nearly new with less than 1000 miles on them.
I'm starting to look for a 340. The 318 Poly in my truck is the original one for the '64 Town Panel we are restoring and we'd like to put it back in for originality. My Dad and uncle both have 340's in their PW's and they have a little more power than the 318's. I have had nothing but troubles with this motor since I put it in last August and it's driving me crazy.
I have had problems in the past with the fuel pump putting out to much pressure. We put a fuel pressure regulator on so we could bring the pressure back down to 4.5-5.0 psi.
I'm out of ideas. Anyways, any suggestions would be helpful.

Thanks

Rob

Mountain Springs Power Wagon Service, Paso Robles, CA

1962 W100-340-LU2 winch
1964 W200-340-LU2 winch
1964 W300-318-LU2 winch
1965 W200 Crew Cab- Cummins Diesel