330-455 OIL PANS
Identification,
interchange and information.
By Greg Rollin
Oldsmobile 330, 350, 400, 425 and 455 oil pans
from 1964-1977 are interchangeable. However, there are several differences
which will be discussed here.
Your basic small block
pan. This style was used on 1964-1977 330-350 applications (including
W-31, Rallye 350, etc.). Note no baffles are used.
Pan capacity 4 quarts. Original GM part number 391440.
1964 and early 1965 pans use this 7/8" 20
thread drain plug. Removal and installation tool is a 1/2" drive
extension. Although in the example above, it would appear that the
"mechanic" preferred a pipe wrench……
1965-1976 big block pan.
As used on all
1966-1978 Toronado pan.
Pan capacity 5 quarts. Original GM part number 398438. Special pickup and
dipstick tube required. While this pan is sometimes used for performance
applications, we don't recommend it. Although you will gain an extra quart of
oil capacity, which will help in lowering oil temperature, this does not
outweigh its problems in a performance application. Because of the clearance
needed for the Toronado's drive shafts, the pan is in
effect, divided into two separate sumps. The front sump has no drainback provision to the rear sump (and oil pickup). The
oil in the front sump area is directly subjected to the crank throws and
counterweights. Which creates windage. Which results
in a loss of horsepower, and perhaps worse, aerated (foamy) oil at higher rpm.
In an effort to contain this excess of thrown oil from climbing the right side
cylinders, at least the factory added the scraper to the side of the pan to
assist in drainback. Additionally, the Toro pan does
not feature the rear sump baffle as used on other big block pans which helps
maintain oil coverage of the pickup under hard deceleration. The Toro pan will
fit most chassis. Which begs the question that if this pan was truly a
performance part, don't you think the factory would have used it on 4-4-2's or
at least on W-30's? We feel the reason and answer is listed (and shown) above.
Above are factory oil deflectors (windage trays). Tray on the left is the rear. It attaches
to the number 4 main cap by the special stud/bolts as seen above. While a third
bolt attaches the rearmost part of the tray to one of the oil pump bolts. The
front deflector is attached to the number one main cap via the special
stud/bolts. The front tray was only used on 1966-1973 Toronado's
and may not fit some other factory oil pans.
The rear tray/deflector was used on 1966-1976 Toronado's, 1972 W-30's, 1973 455 Cutlass/4-4-2's with
manual transmissions, 1974 W-30's and some marine applications. The rear tray
can be used with any other factory (and many aftermarket) oil pans.
When using factory components in a performance
application, we suggest using a standard big block pan along with the rear
deflector for the best results. For all out performance applications, we
recommend using an aftermarket deep pan with the proper pickup.
We stock dipsticks and tubes, oil pumps (standard
and high volume), pickups, pump shafts (standard and heavy duty) and more for
most 1964-1977 applications.
COPYRIGHT © 2002 Greg Rollin/Supercars Unlimited. Any reproduction
of the text and/or images strictly prohibited. All rights reserved.