My F-150 was not good enough to come with a tach. I would like to add one, but I'm not sure which one to get.

The series of gauges I'm looking at comes with two models, an 8000 RPM one or 5000 RPM. I'm thinking that the 5000 would be fine. My math tells me that with my 2.73 gears that 5000 RPM's would be 40 MPH in first gear, I never push the truck that hard.

Thoughts? Will the I6 even spin 5000, let alone above it? I know it's just making noise by then even if it will.

 

Buy the 5000 version. You can rev a 300 past 5000 but there is absolutely NO point in doing so and the engine won't especially like it.

Your HP peak is 3400-3500 RPM and drops like a rock above that point. The E4OD shifts for itself at 3800 at WOT, your manual tranny shoiuld use similar shift points. Above 4000 you're making nothing but noise.

Now if you build the engine up with a ported head, improved intake and exhaut and stuff in a big camshaft you can change all that but in stock form 5000 is more than enough.

 

Agreed. I paid attention today and really rang out first gear. At 35 MPH it should have been about 4400 and it was screaming, not happily revving much higher. Although it would probably hold together, it would scare me to push it much further.

I actually have a dyno graph of one. The numbers were made into an excel graph, unfortunately I don't still have the spreadsheet, just a JPG of the graph. It doesn't drop REAL fast after the peak, it actually falls at about the same rate that it builds. Now above 4000 it probably drops like a rock. I wish we had started the dyno run much sooner so I could see all that low end grunt.



Yeah, but then I'd have to tune it or make it a carb I guess I'll just leave it mostly stock so I can use it as a heavy hauler, rather than a high end screamer. I would still like the gauges though!

 

i have mine set up with a different cam, headers and such plus with the bilt E4OD my WOT shifts are set at 4500 rpm :-D...anything more and it'll start to float valves.

 

That is an interesting graph, I'm used to seeing the torque peak much earlier than that. Is that a completely stock set-up?

 

It may have a higher peak to the left of the graph, somewhere in the 1800-2000 range. Most dyno graphs aren't interested in the zone where the 300 does its best work.

 

Good point.

 

Your ears and your *** will be telling you to shift well before you hit 5 grand!

 

Truck motors aren't made to be high-revving rocket motors, they're slow and torquey. My 351 doesn't like to go over 4000, and it automatically upshifts at 4400. Never wound out 4th gear enough to know if it will go faster than that. What I do know was that it was doing 100 (on GPS since the speedo tops out at 85) at about 3500 RPM, with the E4OD and 3.55 axle. Fast as I've ever taken that truck