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Originally posted by ftyler:
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Originally posted by bake_sale:
[b]Hey all:

I just purchased a 61 Apache 1/2 with an in-line 6 235 and a later 60's saginaw 4 speed. (I gotta finish a few things before I get onto the road.) I don't want to blow the engine running it on the freeway. With this transmission and a Rebuilt rearend with Patrick's 355:1 ring & pinion, can I cruise the freeway without worry?
It depends on where you live. Here in metro Atlanta (and really on most of the interstates in Georgia) you wouldn't feel safe if you couldn't hold a comfortable cruise speed of 70.

3.55 gears even with the tallest reasonable tires on your 61 still will put you in the upper cruising RPMs for a stock 235 at 70 mph. For example 235-70R15 tires will put you at 2988 rpms at 70 mph. That's not where I would want to keep a 235 for distance driving.

I recommend overdrive or just keep your Saginaw 4-speed and go with an even numerically lower gear to make things easier. If you plan frequent interstate travel then try to get your cruise rpms around 2300 to prolong your engine life. I have overdrive on my 66 half ton and with the aforementioned tires and 3.73 gears I turn about 2300 rpms at 70. When the traffic runs faster the overdrive gives me enough extension to travel faster, yet still cruise. At 80 I'm only at a shave over 2600 rpms. That's still pretty easy on my six since I have upped the intake, cam and exhaust.

-ftyler[/b]