problem is the first owner built this and previous owner had no idea either so I wouldn't know where to start haha

so I've been owning my 86 for about 6 months and I've been having this one problem that's really bothering me I have the usdm cluster where the rpm's redline is about at 7.5rpms and mine only gets to 3.5rpms that's as highest it'll go, basicly my redline is at 3.5rpm can't sort that out any help wil...

I'll buy can you ship?