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.
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