New at this anyway my 91 f-250 7.3 has at least 189000 onit and lacks power pulling hills. dealer says compression weak and injection pump weak. compression reads cold 400, 400, 345, 410 400 400 350 410. rear end is 3:55 should i try injectors and rear-end up to 4:10 first or can the motor ? looking forward to you folks advice. Oh yeah, book says compression must read at least 195.

 

The 345 and 350 are a little low when you think of the 10% rule, but they probably aren't slowing you down. The 355 gears are a hinderance when pulling but the 410s limit your top speed. A new pump and injectors would probably make it feel like a new truck again, but without a turbo you'll be seeing lots of trucks pass on the hills.

 

Thanks for the opinion ,I agree with you, I'm also thinking of a k&n air filter and a flowmaster exhaust to give a little more. It's just a spare for pulling the travel trailer so I didn't want to go bananas on cost of upgrades.

 

If you did the turbo it might not be just a spare for pulling the camper.
But the pump and injectors would have to be up to snuff for the turbo to work real well.
The 3.55 gears are fine for pulling weight and still being able to cruise at highway speeds.
As soon as money permits I am going for an overdrive unit on my 7.3 turbo 4 speed 3.55 truck. And I pull serious weight in the WVa mountains.

 

I agree with Spectramac!

The high cylinder 410 and your lowest at best should have been 370..at least..
Sound to me like you have ring trouble or Leaky injectors? -Good Luck-Russ

Or a bad valve in the holes.. Have you run a Lead down test yet?

 

Mine has an automatic w/od. No I haven't done a lead down test or do you mean a leakdown test.. I'm not sure how to do one of those. I've learned to turn the od off when pulling a load but it's good for the highway. I'm not thrilled with any off the 3/4 ton rides compared to my f-150 over these roads. I'd rather use it as my "town" truck. tks, ron