Speedometer out of whack, switched Glide to TH350

2463 Views 3 Replies 4 Participants Last post by  Big Dave
Successfully replaced Powerglide to TH350, on my SBC350, feels like I just got 100 more horses!

Speedometer now reads about 10 mph too fast. Any advice?
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You need a different speedo gear in the trans. What ever car that TH350 came from had a different rear ratio than your 65. Figure your rear ratio, then you should be able to figure out the gear you need. It is just a little coloured plastic gear.

This will help
You could peek at the PowerGlide gear as I believe they used the same color codes. Or at least tell the sales guy what the glide had in it to get a new TH350 gear set with the same number of teeth.

Big Dave
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