Re: [Amc-list] Suggested maximum long-term cruise RPM for 195.6OHV?

[Frank Swygert <farna@xxxxxxx>]

My recollections would say you're correct Tom -- a 2000 rpm cruise speed (in OD) is about right. At 3000 rpm you can tell the engine is really turning! I don't think it will turn more than 4000 in the car (back when I tried such things 20 years ago!), which makes the 138 hp @ 4500 rpm a joke! I couldn't get it to turn that fast in gear going down hill with my foot to the floor! I seem to recall only seeing something like 3800 rpm, but may have been 4200... been a long time! 

Mine had an auto with the optional 3.31 gears, which yours would have standard. I ran 195/65R15 tires, and I don't think the speedo was off much (if any -- maybe 2-3 mph slow?). The 195/70 tires would be closest to stock size. I put 3.78 gears in it (axle from an OD car) and all it did was run the engine at higher rpm cruising. Couldn't tell the difference taking off or accelerating -- though it might have been 1/2 second faster in a quarter mile. That's when I figured out that the long stroke/small bore combo just takes some time to get up to speed and breathing. Give it a good 2" exhaust system -- a turbo muffler isn't very loud, but you can hear it (unlike the stock muffler -- could sneak up on people with that!). And open up that breather! In CA you can get by with a totally open element if you can find a bottom that fits the carb. 

------------------
Date: Wed, 5 Sep 2007 18:17:35 -0700
From: Tom Jennings <tomj@xxxxxxx>

Any ideas? The new AMC six seems most happy (max. mileage etc) at 2500 rpm, 
but it's oversquare, so I assume the old undersquare (long stroke) six would 
be happiest somewhat less than that. 2200rpm at 65mph?

The factory setup (tires, gears) for a twin-stick powerpak 63 American puts it 
at 2250 rpm for 65mph (year 2007) which I hazard a guess meant 60mph at 2000 
might be the olde tyme design cruise spot (it was a long time ago).

My issue is merely tire sizes. There's few left available anything even close 
to factory, and the metric equiv. of factory tire sizes are simply 
unavailable. 195/70-R15's seem to the the smallest practical size.


It's a dilemma between stock, and the rally/rod look which wants low(er) and 
wide(r), but those would throw off the overall ratio, which on this car, with 
little power margin, and inability to rev, matters.

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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