Re: 304/290/200R4 - now V8 Fuel Mileage

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: dsoutherland@xxxxxxxxxxxxxx
" 
" I have followed this whole thread with some interest to see what input
" would be shared.  I feel like the original direction of the thread was
" abandoned somewhere along the way.  I would personally like to hear
" input on the subject of increasing fuel mileage on an AMC V8 powered
" car using modern technology and parts that are available.
" 
" What seems to be reasonable options for manual transmission selection
" would fall into these choices:
"      1) Use an AMC T-5.  
"      2) Adapt a Ford T-5.
"      3) Use a T-4 or SR-4 with numerically low rear axle ratio.
"      4) Adapt a GM T-5.
"      5) Adapt a Richmond 5 or 6 speed.

imho for any v8 the t4, sr4, and amc t5 are out; they're all rated in
the low 200s ft-lbs.

for a 290/304, the ford 5.0 t5 is a fairly trivial adaptation.  but
even the svt t5 is only rated 330 ft-lbs, so it's a little iffy behind
a 343 or 360 especially in a heavier car.  not impossible with a
little care though.

gm t5 - no points, unless one falls from the sky.  but a gm-style
aftermkt t56...  i know of one that's been done.

richmond - $$$, double a new svt t5.  overkill for small v8s, but 6sp
is nice.  tough enough for a 401 though.

another thought - ford toploader with jeep t17x-family gears.  i keep
forgetting which is which, but there's a t176, t177, and t178, and
3.01, 3.52, and 3.82 1st gears, and easily strong enough for a 360
even in a wagoneer.  you can also use the h/d toploader 31-spline
mainshaft.

" For Automatic transmissions;
"      1) Adapt a GM 700R4
"      2) Adapt a GM 200R4
"      3) Adapt a MoPar 500 or 518 series.

for mopar i think the only choice starts with the 42re from the 4.0
grand cherokee and de-electronifying it, and i've heard different
things as to whether this is easy or even possible.  cool though.
there's no other 4sp case with amc pattern and afaik there's no 
superbell that could be used to adapt.
the 42re is roughly a500-tf999 size, good up to a 360.

" In all the cases above, rear axle ratio selection for the body/engine
" combination would be a factor to consider.
" 
" Then there is always the carburetor/camshaft/engine combination that
" comes into play.  And, of course, fuel injection can be discussed.

cam is very important if you want to pull those tall gears on the
highway!  as frank has found out, you can sometimes get better mileage
at -higher- rpm, if that's the way your engine is set up.

'lugging' it is not a good idea.

generally, your engine will be most efficient near its torque peak.
if you want great highway mileage, you want a cam that moves that peak
down toward your highway rpm.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen

adh@xxxxxxxxxxxxxxxxx                       and think what none thought