Tires and Gears

[Blue95]

I by all means dont want to open the engine up to 2900rpms for a long period it sucks fuel now as it is without any load. Alot of my friends stick with 4.10s in thier 10 bolt and have no issues. Looking back at the gear ratio calculator, 3.73s with 31s would almost be the same be it a 4.56 with 37s both doing 70. My only option for solving any sory of high rpms at 70mph would be to find a tranny with autodrive with low miles or convert it to a 5 speed stick, which at this point in my build would not be all that hard

Well my question would be how much road driving will you be doing with this truck, city and hwy? if this truck was going to see trails some or a few times a year but be a weekend warrior to cruise and have fun then I would stick with what you have now with 37's. But if the truck is tore a part swapping in a built 700R4 or doing a 5 speed swap would be easier now then later, I guess it depends on how deep your pockets are and how much work you want to do.

 

[4x4incountryboy]

I have pics on my profile of the truck. Its a little further then shown however it still needs to be painted and reassembled. I want the truck to be a dd if needed but will go stored away in winter months. I would estimate travel around tops 50-75 miles a day maybe more on occassion

 

[Blue95]

THen if you are going to keep the Turbo 400, which if it is good and in there then I would keep it IMO, then if you are going to run 37's I would just keep your 3.73's, that would put you at 2400 RPM at 71 MPH which is good for driving that far each day and will keep the engine in its power band to roll those big tires.

 

[4x4incountryboy]

I am gonna have to atleast for a while, my friend blew his rear last night wheeling so I sold him the one I just picked up for a hundred and fifty bucks. Curiosity though, roughly how much would my speedo be off and is there a way to calibrate that difference so the speedo will read accurately

 

[Blue95]

That I cannot answer, I do not know how a Turbo 400 works, but being all mechanical I bet there is different speedo gears or something that can be swapped in.

 

[4x4incountryboy]

Thats what I was thinking but again I have came across stranger things

 

[outalne94z71]

That I cannot answer, I do not know how a Turbo 400 works, but being all mechanical I bet there is different speedo gears or something that can be swapped in.

speedo was mechanical till 88 when it went electronic, mechanical ones get a ratio adapter gear box screwed between the cable and the case output to fix the ratio change, electrical ones you need to modify the drac with dip switches or if using in a 88-91 truck you need to reprogram the speedo itself

 

[Blue95]

speedo was mechanical till 88 when it went electronic, mechanical ones get a ratio adapter gear box screwed between the cable and the case output to fix the ratio change, electrical ones you need to modify the drac with dip switches or if using in a 88-91 truck you need to reprogram the speedo itself

Gotcha, well glad that is cleared up. so the OP could mod his to read correctly fairly easy or have it done.