Hello everyone I have a question about the engine in my truck that I could not find an answer to elsewhere.

It has the 5spd manual and originally came with no tach. I put a tach in the truck and I find that my rpms are much higher than expected for just cruising around. To go 70 in 5th im at 3500rpm! My normal cruising rpm is around 3000. If I shift up to put it around 2k I have lawnmower power and tons of power lag.

Is this normal for this engine?

 

I would look at the label on the drivers door and see what axle you have.
3.73 was the usual but yours could have a 4.10, people ordered 4.10 axles if they would be pulling trailers.

 

I have a 3.45 ratio.

 

Did you get the right tach wire? Since the clusters were used in the expo which came with the 5.0 it may be reading as if its a v8 which could throw your numbers off 3500 with 3.45 is a lot at 70 i cruise at about 3000 maybe a little more and i have 3.73 gears. Id bet its a wiring issue with the tach and not mechanical.

 

I had my mechanic install it. I will double check his work and I know for a fact the tach is set for a v6.

What would you guys do if my mechanic did in fact wire this wrong? I did take it back to him saying the rpms were way too high and he said there was nothing wrong. Is it reasonable for me to ask for a refund?

 

With 3.45 axle, 5th gear at .79 and 26" tires at 70MPH, engine RPM would be 2,500

So either the tach or speedo is off

 

Edit to my earlier post i had it on the freeway today at 70 with 3.73 gears and In 4th i get around 2800 in 5th i get about 2400 rpms. Something in your gauges is off. I hit the governor at 90 before it will even see that kind of RPM

 

Problem fixed, thanks everyone.

 

Any insight into how it was fixed might be helpful to others down the road