[VAC] I-6 and V8 for towing

[harriswest <harriswest@xxxxxxxxxxxxx>]

Stuart and Bonnie, 

With regard to an in-line six versus a V8, the following numbers are
typical:
Ford 302 V8 (4.9L)..............Ford 300 I6 (4.9L)
185 HP @ 3800 RPM...............150 HP @ 3400 RPM
270 ft/lb @ 2400 RPM............260 ft/lb @ 2000 RPM
Bore 4" by stroke 3"............Bore 4" by stroke 3.98"	
Compression ratio 9:1...........Compression ratio 8.8:1

The numbers are all very similar, as could be expected with similar
displacement engines from one mfr.  The differences, though slight, do
have an effect on drivability.  Note the V8 produces more HP, but at a
higher RPM.  Torque is very similar, but look at where it's produced -
only 2000 RPM with the in-line engine against 2400 RPM with the V8. 
Subjectively, this leads to comments about the I6 such as "it hits a
wall when you try to rev it, but it'll pull stumps all day." 
Particularly if the driver is used to V8 or V6 engines.  

The slightly lower compression ratio of the six leads to a slightly
greater tolerance for bad gas, really not a factor in most places.  My
own tow vehicle is a 1963 Willys 4WD wagon with a compression ratio of
7.3 to 1 and it will cheerfully burn anything with an octane rating
better than, say, canned fruit cocktail.  I can even feed it the regular
Pemex in Mexico without hearing any complaints.

I happen to like the straight-sixes a lot - they are simple and
reliable.  Fitting one with a progressive 2BBL or 4BBL carb and a header
exhaust does a lot for the high end horsepower without too much mileage
and low-end performance penalty.  BTW, I also hate-hate-hate automatic
transmissions and wouldn't own a car with one if it were given to me.

Vehicles with auto transmissions, however, are much more forgiving to
the less experienced tow-vehicle driver... and without comment on
whether it's you or the spouse, the less experienced one will be driving
at least part of the time, right?  (as a cloud of clutch smoke drifts
across the campground to spoil everyone's dinner)...

However, preference aside, availability counts for a lot - hence my
earlier recommendation for a V8 with an auto.  3/4 ton V8 trucks with
automatic transmissions are ubiquitous, therefore it might be easier to
obtain one and keep within your $5K budget.  A vehicle equipped with a
V8 can readily be modified in other ways to make it more appropriate fot
the task, e.g. replacing the axle gearing or re-camming the engine to
produce more power at low RPM, but of course this costs money.  You may
luck out and find one with a "tow package" that needs no modification at
all.  

If body style is a factor, that is, if you don't want a pick-em-up and
would rather have something with real room for more than one passenger
and/or an enclosed cargo area accessible from the front seats, you're
pretty much stuck with the V8 / auto trans.  Oh yeah, there's the Toyota
Landcruisers but good luck getting a low-mileage one of them for five
grand.  

So, that's my two cents.
-- 
Mike Harris
Austin, TX
mailto:harriswest@swbglobal.net