Interesting bit of info. Returning from the 20th in my 88 3.4 coupe with the stock ratio (3.33?) Formula automatic. My friend is driving his 3.4 with the 4.10 M19 4 speed. We're comparing notes over the radio. At 80 MPH, I'm turning 3500 RPM. At 80 MPH (76 indicated on his speedo, due to the size of his tires) he's turning... 3500 RPM! I expected that he would have been wound much tighter than that. Never thought tire size would have made that much difference. His are 235/60-15s, where his speedo gear is looking for 215/60-14s. Mine are stock diameter (identical to 215/60-15).

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Raydar

88 3.4 coupe. 17s, cut springs 'n all.

The forth gear on the 4:10 muncie is like an overdrive. It has a ratio of something like .9 :1 Hence with larger tires the FDR in the 4:10 tranny can be about the same as the A/T with a 3.33 FDR.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://www.turbochargerpower.com/turbo.htm

The ratio for the 4.10 4th gear is .73

Ok whats going on I have a 4.10 in my 85gt and at 60 mph its running about 3200 rpm? would 300 rpm take it up to 80 mph? I will check this out tomarrow and report back..

Earl,
Remember, he had huge tires on his car. His indicated speed was like 75-76, even though he was really doing 80. I'm not even sure how accurate that 80 (on my speedo) was. I know that whenever I passed one of those radar operated speed signs, that it matched my indicated speed fairly closely, though.

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Raydar

88 3.4 coupe. 17s, cut springs 'n all.