Here's what I've got...1983 Ford F-150 extended cab, 351w, C6, 3.55's...weighing in at a hair over 4900 pounds. It's got a 40K mile stock rebuilt 351w out of an '89 Bronco, measured 8.5-1 compression, stock EFI cam (206/221@.050, .444/.453 lift, 115 lsa, 117 ica), stock rebuilt E7 heads, a Weiand Stealth intake (was purchased to match future plans I had for the truck), a 80457 600 vac sec Holley, stock '83 exhaust manifolds, 1 3/4" down pipes into a "Y", 2 1/2" single exhaust, no cat, Flo-Pro race muffler, and a Mallory HEI. I advanced the cam 4* trying to perk up the low end...all it did was make it run a little rougher. Other than a spike in power between 3500 and 4500 rpms, this thing is actually weaker and gets less fuel economy than the thoroughly worn out turd that was in there before...and it had a smaller cam (107.5 lsa though), less compression (7.9-1 measured), and a TON of blow by. The old engine averaged 13.3mpg highway with a best of 14.5mpg one time with a strong tailwind...the fresh engine averages 10.4mpg even after extensive tuning.
I'll have 1 1/2" long tube headers and dual exhaust on it within the next month or so.
Selecting a cam for this thing has been quite confusing. I need to add some economy to this thing, along with a much stronger 2000-4000 rpm torque curve. I initially expected much better performance out of this engine, although I knew the super wide lsa and huge duration split wasn't going to help low end and midrange torque, I didn't expect it to be this bad especially with the corked up exhaust. Doing some research, I found the .006" numbers for the EFI cam...284/308!!! No wonder this thing doesn't want to idle much under 1000 rpms and doesnt pick up until 3500 rpms! This is actually the very same profile ford used on the early 70's 351 Clevelands. That has got to be the slowest take up ramps in history. How in the world was Ford able to get this turd to pass smog regulations with 63* of overlap??
So I was looking at getting a cam ground for the 351w that I have had excellent results with in the past on low compression, smogger headed 350 chevies, the comp cams 260AH-8. But then searching the net, most everybody claims wider lsa=better vacuum=better mileage. My experience has been that smaller cams on tighter lsa's=sharper throttle response and much stronger torque through the whole powerband (talking 0-5000 rpms here), so my thinking is stronger torque=less throttle input to maintain speed or pull hills or whatever which should equal better mpg's. Thoughts? Keep in mind the relatively high cruise rpms (3200-3400 rpms), heavy weight, and large frontal area.
More searching on the whole LSA thing and cam timing events and what not ended up with me on some magazine article written by David Vizard (whom I highly respect) concerning the optimum LSA versus valve sizing. I'm going to do some light porting on my E7's but wont be spending $$$'s for larger valves and the corresponding machine work required. Not worth the money in my opinion, especially for what I use this truck for. According to Mr. Vizards charts, I need a 104 LSA
So using the 260AH-8's 48* of overlap, his article says I need a 256* cam on a 104 LSA. Sounds like headbanging to me...once when you punch it and it smacks your head against the back window, and again when it falls on its face at 3500 rpms and your head hits the steering wheel 
Thoughts? It just doesn't seem realistic to me...especially with the weak ford exhaust port.
