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**kwmech** · 03-05-2023, 12:35 PM

If you have the 235/85r-16s on it (which are 31'' tall) A 3.73 ratio would be accommodating. My big blocks like to live around 21-2200rpm on the highway. But my flat bed has a t400 with 4.10s and a gear vendor with 31'' tires, then my 68 has an SM465 with a ranger OD with 3.73s with almost a 33'' tall tire, so..... if you do any heavy towing with the 3.73s you'll see an increase in transmission temps and a somewhat struggling 454 unless you bump up the compression a little and go with a mild cam.

03-05-2023, 12:35 PM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,406	Re: How many rpms does a 454 like on the highway? If you have the 235/85r-16s on it (which are 31'' tall) A 3.73 ratio would be accommodating. My big blocks like to live around 21-2200rpm on the highway. But my flat bed has a t400 with 4.10s and a gear vendor with 31'' tires, then my 68 has an SM465 with a ranger OD with 3.73s with almost a 33'' tall tire, so..... if you do any heavy towing with the 3.73s you'll see an increase in transmission temps and a somewhat struggling 454 unless you bump up the compression a little and go with a mild cam.