I have been reading for hours now about the tach mod. i now know how to do the mod on 1987+ trucks, but my 84 (not sure about 85) uses a different tach then the 87 and 89+ tachs that ive seen.

here are some pics of my tach, im still yet to find any pics or info on a tach that is from an 84 or looks like this one.

 

http://www.mindspring.com/~jayk3/toyota/tachmod.htm

This surely isnt as simple as what most of us did with out 89-95 gauges but it should work i would think.

I would search around Pirate4x4 if you have not already. You may get more results over there for the earlier model

 

thanks for that, found that last night and plan to try it today if i can find the 5k pot needed.
as for pirate, i probably spent an hour on there last night. one guy had an 87 which i thought would be the same as mine since it is the same cluster but it looked completely different from the back. another guy had my style gauge but gave up after 2 failed tries.

 

spent about 2 hours on this today with my dad. gave up, he knows a fair amount about this stuff and had his scope and everything out there, but no luck.