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T98 output shaft-speedo gr types? speedo gear ratio adaper

Posted: May 17, 2017, 11:51 am
by aj64f100390-292
Hey guys, my y block is close to being able to be assembled..but my speedometer is off, and I've already changed the driven gear to the smallest number of teeth yiu can get-18 tooth. And when I remove my 390 I'm wanting to remove and paint my t98, after replaceing the rear seal, and get the odometer right so that when I build my final y block, I can know exactly, or real close to how many miles I've put on it. So I'm wondring what tailshaft/ speedometer drive gears there are to choose from, because dads pretty sure the last time he had the back end of the t98 apart that the drive gear was made to the tail shaft..-if I'm remembering his wording right-I'll double check this evening and change my post if I am. And it uses the steel speedo driven gear, Ill post pictures as soon as I can but it uses an identical speedo gear as my t98 laying around out of my 62 f600 floor doner truck. So can I change it to a more common speedometer gear set up cheaper than what it would cost me to just get a speedometer gear ratio adapter? On ebay I found one person selling new ones for 83 bucks ranging from +11%-+100%. Right now 40 is 45, the speedometer starts reading inacurate a little before that but it starts reading a 1/2 mile per hour off...if im not mistaken but I probably better double check with my speedometer gps app one more time.

Thanks in advanced

Re: T98 output shaft-speedo gr types? speedo gear ratio adap

Posted: May 17, 2017, 3:38 pm
by bobenhotep
Does anyone know if a t98 can run a speedo gear off of a t18 or t19? If you could run the later gear you would have a lot of options.

Dan

Re: T98 output shaft-speedo gr types? speedo gear ratio adap

Posted: May 18, 2017, 6:26 am
by bruceandersson
If you already have the smallest gear, you will need the head repaired. There is either too much resistance or too little magnetic charge. A good speedo shop can address either.