Just curious, what's my redline supposed to be on a 90 F250 w/ 5.8l, 5spd, and 4:10 gears? It needs a tune up and I plan to do a 6 liter tune but it seems my truck does not like to go beyond 2,800rpms. Is this normal?

 

Not at all. The engine should be able to rev up to the full 6k rpms on the tach. I would NOT recommend going that high, but it should be possible.

 

If you're having issues revving replace the fuel filter first, replace cap, rotor, wires, and plugs. Verify timing is at 10dbtdc with SPOUT unplugged. If it still does it try dropping the y-pipe off the manifolds and see if it clears up. If so you have a plugged cat if not you have a clutch or transmission problem.

Redline is 5250rpm and that's also where the rev limiter is set.

 

I'll just add that while the engine can mechanically rev to 5000rpm no problem the powerband produced by the stock cam, heads and intake starts to drop of above 3500rpm so there's really no point in reving it past that point.

 

Mine shifts around 4500 (same gears and engine, but a C6.)

 

Thanks guys. I can only assume this motor has 113k on it and I have no intention of revving it past 4k. I just found it odd it did not like to rev to 3k. The clutch has been replaced so next step will be fuel filter and tune up. The fuel filter on it now is a motorcraft so who knows, it could be original to.