Hello there. New member here but have read around a bunch

I have a 1990 F150 4x4 with a 302. Have had it for bout 4 years. Not sure what its got for gears, 3.73 if I had to guess. When I bought it, I drove for 5000 miles and the odometer rolled over for the second time I believe. It was a tired old motor, not a lot of power but got 12 - 17 mpg

A year ago I was goin to work and it lost nearly all power and was smoking out of the crankcase breather. It had burnt a piston. I found a 2wd that was split to make a pickup box trailer. The owner said the motor had 40k on 'rebuild' and bought it. We pulled the motor out of the 2wd and put in new main and piston bearings and new oil pump. On reassembling the new motor we used some of my parts that seemed to be in better shape. Some of the 2wd injectors had cracks in them so we used the set out of the 4x4. It ran good and had better power for about 250 miles. Then burnt another piston. The injector was dumping raw fuel into the cylinder.

Now in pulling the motor again to redo it . . . AGAIN. I was thiniking about an 'RV' cam. I had heard that it gives it better low end and possibly fuel milage. I tow once in a while but not too much, thats what the Powerstrokes for. A boat or a load of wood, not too heavy. Its kind of my car. I use it for highway back and forth because I cant bring myself to buy a car. I just wanted to know if I had to change anything else other than the cam. Like rockers?? Or lifters?? Im hoping not but better ask someone who knows.

Sorry its so long winded just wanted to get all the facts out there.
Any help would be greatly appreciated

- Jake

 

If it's roller lifters, you can reuse them. If they're flat tappet, you need new flat tappet lifters, and need to use break in engine oil, and run it at different RPM's between 2500-3000 RPM for 30 minutes after installing the new cam.

 

The Comp 31-255-5 cam and lifter kit is an RV style replacement for that motor(flat tappet) that is also compatable with the EFI system, combine that with longtube headers and you'll see nice power gains across the board with increased milage when you're not standing on it. That motor has a flat tappet cam in it from the factory, and while it could be converted to a roller that would cost 3 times what the flat tappet version would so it's not the cost effect route. Besides the cam and lifters a new timing chain is always a good idea if you're rebuilding it anyway.

 

X2 on what Conanski said. I took his advice on my '90 rebuild and went with the same cam and have JBA headers installed. Also went with Scorpion roller rockers.

Side note...I bought a complete Comp Cams kit from a place located in Richland, MS. They were located on E-bay and I also purchased the pushrods I needed there as well. That included the cam, lifters, and timing chain. I also purchased comps break-in lube and oil for the intial assembly. Was about $235, IIRC...

Another thought, as this was my 1st rebuild and my machinist didn't ask me, but be sure to inspect each valve carefully. If they aren't smooth, I would suggest going with new valves for the heads, since I lost a valve cap between picking up the heads, assembling and breaking the motor in. Hindsight is 20/20, and it's a small cost as to completely having to pull the heads on the motor again.

 

i agree with virtually everything tht wassaid, but also get your heads ported and polished, new valves and it cleans it up for better flow too, along with the 6litre tune up