Re: Those with 4 cylinders I need some info on jetting

[tsm1@domain.elided (Tom Mandera)]

>I have a rebuilt single barrel Holley on a 4 cyl rebuilt 4 cylinder
>196(rebuilt done 1992; original year made 1971).  The new carb came jetted
>with a 70 main jet; the manual reccomends either a 45, 52, or a 53.  I tried
were using with reference to gas mileage and grade.  With the 70 main jet I
>was getting 8 to 10 miles per gallon in the city (Mostly driving up hills in

Matt,

My '77 Scout II came to me w/ a '76 196-4cyl, and a 1940 carb (no visible
float bowl).  This carb had somethign like the 53 jets or so you mentioned..
(or was it the other way around?)... I changed it out for a 1920 (visible
float bowl), which had 70s (again, one had one, one had the other)

The IH shop manual calls for these jets for the respective carbs... both
were offered on the 196.. I imagine different years.

I drove the Scout with the old carb to the NW Binder Roundup last year.. on
one leg, I hit 24mpg... I would usually get 18mpg or so on the highway, and
over 12mpg in town.

That carb went south (cracked base, and it needed an overhaul anyhow).. I
located a N.O.S. 1920 for $25 (which was .26 less than the rebuild kit for
the 1940) and installed it.

I can't remember what initial mileage was.. my first gut feeling was
performance went down some... 

I remember getting 8-12mpg in town some time after that, and 15mpg or so on
the highway... not great, huh?

When I bolted my 33x12.50s on (4.09 gears), mileage sat around 10mpg in
town, and became a dismal 12mpg on the highway... that is, if I wanted to
keep 65-70mph (if I could).. I was deep into the throttle and it wasn't
accelerating.. just underpowered.  

On the trip from Fairplay to Leadville via Weston pass, I didn't exceed
45mph, and I hit 20mpg.  For the rest of my 3600 mile road trip this summer,
12mpg was the average.  :-(

I think this was a case of just asking too much from the 196.  The 304 V8
that replaced it is still getting tuned... but 13mpg on the highway is
average (@65mph.. still have some top-end issues to iron out).. while
mileage in town has been bad (5-8mpg) due to 1) my driving habits, and 2)
still needing to tweak things right (the top-end plug fouling is my primary
concern right now)

-Tom