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

[Tom Jennings <tomj@xxxxxxx>]

On Wed, 11 May 2005 fljab@xxxxxxxxxxx wrote:

> On 304 vs 360 mileage, I see that from a torque standpoint, that
> running the 360 would be a better choice, but I'm sure there's a
> point of diminishing returns as for normal driving, how much do
> you need?  I DO want to run a V8, but what would be realistic
> returns on power from both engines set up as a torquey, gas
> mileage type engine?

I'm thinking of this: ignore what you COULD get from the motor;
you know where that route goes and how to get there. That's what
your 390 is for :-)


Since a big (360) engine has the same mass, parts, cost etc of a
little (304, 258, 232!) motor:

 * there's no penalty for using the "big" block
 * there's no advantage to using the "little" block

We know that very generally, low RPMs is pleasant to drive, easier
to tune for (induction/exhaust issues; valve lift/area; valve
spring tension & losses, etc), lower drivetrain losses (churning
fluids). Torque is the one way to get all this.

(The one down side to torque is parts need to be strong, relative
to total HP (look at the little parts in modern high-revving
4-cyls!), but 60's/70's AMC parts are basically all strong enough
within the limits already discussed.)

So the 360, with factory boat-anchor 2bbl manifold (or equiv.
FI), small heads, single exhaust, steep axle... don't think of it
as THREE HUNDRED! AND SIXTY! CUBIC INCHES! think of it as a thing
with a specific purpose -- fuel-efficient low-speed torque.

Hey we just reinvented Rambler.




PS: Did I just talk myself into building a 360 to go behind my
T150/OD?