Alright guys I tried to figure out the speedo ratio but I couldn't do it. I need to know what speedo gear would I need to get for my 89 IROC its a L98 with the 2.77 well I m getting a rear from a 92 305 with a 3.42 what speedo gear do I need for it?

 

well I called up chevy today and they couldn't tell me what was what. I pretty sure it's a gear I need, they said it was a sensor. So if anyone could give me some advice I would apprecite it. Thanks guys

 

come on someone out has to had put a speedo gear in there car, that went to the 10 bolt 3.42, from the 2.77 Anyone?

 

Auto or stick?

 

Oh sorry, auto well I did some looking in the post to do my swap will the 15tooth and 41 tooth work?

 

With 245/50/16 tires, that is the correct gearing.

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1989 IROC-Z 5.7L
NOS 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System