[net.auto.tech] Engine Performance Mods

eric@amc.UUCP (Eric McRae) (12/17/85)

[Na Na Na, you can't catch m~2

I have a '78 Trailduster.  This is Plymouth's clone of Dodge's
Ramcharger, a big 4WD tank.  The rig is generally in good shape but
I'd like to try to improve the engine's performance.

The power plant is a stock 360 CID with a Holley 2 barrel, and single
exhaust.  It has BoKu (metric equivalent of "lots" :-) low end torque.
It is rather gutless however, at cruising speeds and gets 8 MPG on a 
good day.  The thing is 83K miles old.

Here are some of the things I'm considering:

1.	Headers and dual exhaust.
2.	Intake manifold (4 barrel carb???).
3.	Non-stock cam (and solid lifters?).
4.	Port polishing (Does it really help?).

I'm not too interested in the economics of the job.  My goals are to
improve gas mileage and cruising range performance.  The engine is
currently in good health but it will get a good head and ring job if I
open it up at all.   I'd like to hear from anyone who has experience
with these things.  Whose headers, cams, manifolds are best?  How much
does each of these things help?  Thanks in advance for your comments.

Eric McRae   ..uw-beaver!tikal!amc!eric

bellas@ttidcb.UUCP (Pete Bellas) (01/03/86)

In article <143@amc.UUCP> eric@amc.UUCP (Eric McRae) writes:
>
>I have a '78 Trailduster.  This is Plymouth's clone of Dodge's
>Ramcharger, a big 4WD tank.  The rig is generally in good shape but
>I'd like to try to improve the engine's performance.
>
>1.     Headers and dual exhaust.

Very good choice. Don't go for "competition headers", stay with small
primaries (1 1/2 inch or < ) and small collectors (3 inch or < ).
Also consider the "alumacoat" finish as they remain in new condition
almost for ever (8 years + for me).

>2.     Intake manifold (4 barrel carb???).

Good choice.  As above stay in the "small" range or you will lose all
that bottom end.  A 600 cfm on a "torker" or "SP2P" style manifold
(those are edelbrock names, but there are a lot of others) works well.

>3.     Non-stock cam (and solid lifters?).

Maybe.  A good "mid range" cam is as high as I would go, you want one
that will leave you with a good idle and some low end torque, there is
nothing worse than a 4WD that has no power below 3000 rpms!  As for the
lifters, stay hydraulic.

>4.     Port polishing (Does it really help?).

Nay.  I have done it on engines and until you get into HIGH rpms it
is of little value.

5.      Balancing

This is my addition to the list.  If you are going to have the engine
torn down by all means have it balanced.  A street balanceing job
(+- 1 gram) is only about $75 and makes the engine run noticeably
smoother.  It is one of the few things that give you more power and
better economy!

Good luck.

/<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>\
^                                                                          ^
v   Pete Bellas             "When it is not necessary to make a decision,  v
^   Citicorp TTI             it is necessary to not make a decision."      ^
v   Santa Monica, CA                Lord Faukland                          v
^                                                                          ^
v   Path: ...!{randvax | trwrb | philabs | vortex}!ttidca!ttidcb!bellas    v
\<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>/