I got a 78 f150 4x4. The truck is tuned well and has some goodies including a Holley 600, weiand intake, hedman headers, 4.11 gears, np435, 32'' tires, and some radical cam. My problem with the truck is that it is not really a great daily truck. I am seeking more lowend performance and gas mileage. Even with 4.11 gears and the 4speed, the cam that the previous owner put in does not wake up untill after about 2500 rpms and then it revs to the moon. That is crappy for around town, trying to pull hills, and towing. I am thinking about swapping in 3.50 gears for better highway mileage but I'm reluctant to do that since the engine will be a dog. I think a cam swap is a must. Seems like you guys like the Compcam 255DEH. Lowend performance and better fuel mileage is what I'm looking for. With the cam in the truck now, its like a lightswitch, power is either on, only in high revs, or off in anything below 2500rpm..... I hate it. My question is, since the previous owner already swapped the cam and it probably has the necessary valve springs and stuff, do I need to go for the complete kit or just the cam itself? I really really want to swap the 3.50 gears in but this big lumpy cam is stopping me from wanting to do that.

 

I fell for the 256XE for the lift and a bit more aggressive down low. But i went roller and had comp bust out a custom that is similar. 255deh was 2nd choice.

cam is important but even more important imo (from everyone elses experience) is compression. If your running stock pistons and heads one of them has got to go - cheaper way (if the motor is out and being rebuilt) is to keep the heads and replace the pistons with flattops- can get them for 170 or so- that will give you 9:1 cr and the xe or deh cam is perfect for this.

Other option is the auzzie 2v heads as sold on ebay- go mine delivered for a little over $400.00 off ebay- you can keep the bottom end the same and put the heads on for about 9.5:1 CR- apparently these heads have better quench and many have build them and run 87 pump gas with low end cams.

I'd go to TMI's site and read up on his build and he sells the parts- real nice guy- sponsers the 335 forum. I spent $0 on a rebuildable long block from a fellow FTE member MTFLAT..great guy! So I've been driving my '77 and working on other things as i can while i'm building the 400. Makes sense cause you never know if the block in the truck is already 040 or something and you can get the spare for next to nothing and not be in such a hurry.

 

for some reason I could't edit but remembered that putting fresh heads- especially closed chamber on a weaker block could cause issue with rings etc. Also headers are said to be worth about 30hp on this motor(?). Also you didn't say whether or not yours is a 351M or 400. I'd fnd a 400 to build if it was a M- wouldn't waste my time or money on the m-imo of course.