Speedometer Drive Gear, Fuel Tank, Old Turbo....Need Info/Advice

[79GLIDE]

I have a variety of questions I would like help with:

The speedometers in both the '87 and the '90 are significantly off, over by 10MPH. As you can see in my Sig, the '87 has a C6/3.54, and the '90 has E4OD/4.10 set up. Both run 265/75-16, which is a wider tire than the 235/85 tire that is spec, but diameter difference is negligable(0.080"). Anyone out there know which color speedometer cable drive gear I need for these applications, or am I going to have to trial and error using salvage parts until I close? If I remember right, the Ford garage was no help last I checked(obsolete part).

My rear tank has developed a leak. I located an '87 6.9 at the bone yard. Anyone know if that tank will work in my '90? The truck looks like it went to hell on a passover mission, but it does have an aftermarket turbo on it. The intake parts are gone, but the turbo is still mounted to the motor, including oil line. The down pipe is disconnected, but is still there. I can feel a small amount of play by wiggling the impeller, but it's not enough to see it move. $50 will buy whatever is left of the turbo setup. Is this worth messing with, and if so how do I ID which turbo it is ATS, Banks, etc?

Any help is greatly appreciated.

 

[79GLIDE]

Anybody on here have a clue which color drive gear I should be searching for to get my speedometer close on my stock equipment? Ford garage says there is no way to look it up by application.

 

[Billyisgr8]

I don't know the color I didn't see it, but I know that my spedometer was also 10 kms to fast ( 6 mph) , so I went from a 20 tooth to a 21 tooth drive gear which is the most toothed gear the tranny shop had available, and that made up my 10 k difference. I also have a 4.10 with E40d running 235/85/16. The tranny shop charged $5.00 for the gear which they replaced the same time the tranny was out.