I have put the engine and ZFhp22/LT230 from a 1987 RR into my project 90 frame (it was a 2.5L NA diesel and the diesel was dead). I have a VDO speedo that I would like to use with the later speed sender that fits to the t-case. If I do this how do I keep the ECU happy, it has a sender that is fitted mid way along the speedo cable right now. Any help would be great. Thanks.

You could try to use the new speed sensor signal for the ECU input. If if does not work you will need to have a cable made and use the original speed sensor for the fuel injection and then a short cable to a GM style speedometer output. This make sense?

JP

Yep... that was my back up plan.