The Ford Barn

38bill · 05-26-2019, 07:42 PM

Just finished putting a tach in my truck and got it out on the road. Flathead is a 59AB @ 80 over. Transmission is a '85 T5 (S10) with .72 overdrive and 28.5" dia tires. First road test showed 1800 RPM at 60 MPH. I thought that was off so I checked the speedometer today with a good GPS unit and the speed shown is correct. Drove it again today and got the same readings. Went to a RPM calculator to see what it would come up with and it said exactly the same, 1800 RPM for 60 MPH so the tach is right on. Couldn't get up to 70MPH on the local roads but the calculator says it would only be 2103 RPM. I have no problem with the engine making enough power at speed, its the noise and rough ride that are the main issues.

05-26-2019, 07:42 PM	#21
38bill Senior Member Join Date: Apr 2014 Location: Minnesota Posts: 1,165	Re: 49 f1 PU T5 Just finished putting a tach in my truck and got it out on the road. Flathead is a 59AB @ 80 over. Transmission is a '85 T5 (S10) with .72 overdrive and 28.5" dia tires. First road test showed 1800 RPM at 60 MPH. I thought that was off so I checked the speedometer today with a good GPS unit and the speed shown is correct. Drove it again today and got the same readings. Went to a RPM calculator to see what it would come up with and it said exactly the same, 1800 RPM for 60 MPH so the tach is right on. Couldn't get up to 70MPH on the local roads but the calculator says it would only be 2103 RPM. I have no problem with the engine making enough power at speed, its the noise and rough ride that are the main issues.