1970 BB Oil Pan

[Charles W.]

[Joe L.]

Re: 1970 BB Oil Pan

I’m looking to replace the oil pan on my stock 1970 LS5 with power steering. In a previous life someone made a really bad repair in the plug area and it leaks. I don’t plan to remove the old pan until I get a replacement. I was looking for the GM part number to make sure I don’t buy the wrong one but can’t locate it. I would appreciate if someone could give me some guidance on this.
Thanks for you help

Charles------


The original part number was GM #3977591. However, this was a pan UNIT so it's not the part number of the actual pan, itself. The UNIT included the pan + other components, probably a gasket set and/or external baffle. The only difference between this pan and earlier 1965-69 Corvette big block pans was a relocation of the internal baffling to accommodate the longer stroke of the 454 engine.

GM #3977591 was discontinued from SERVICE in January, 1985 and replaced by GM #14091356. The latter was also a pan UNIT and also included a GM #3967854 external baffle ("windage tray"). In this case we know the actual part number of the pan because some examples have it stamped on them. It's 14095705 but that's actually an academic point because the pan was never available under that part number.

The 14091356/14095705 pan is very similar to earlier Corvette big block plans. The differences include a slight revision of the oil pan rails and the elimination of the corner reinforcements. When this oil pan is used for 1965-69 Corvette applications the external baffle, included with the pan, should be used to replace the existing baffle (that's why the baffle is included in the pan UNIT; it's not necessary for 1970-74 applications which should already have that baffle installed).

All Corvette big block oil pans are Corvette-only pieces and were never used for any other Chevrolet application.

Unfortunately, the 14091356 was discontinued without supercession about a 20 months ago.

[Mark E.]

Re: 1970 BB Oil Pan

I purchased a new pan from Chevy for my 454 about 5 years ago. It was still available then. The only difference with the service pan is it didn't have the corner reinforcements spot welded to the lip. I purchased those separately and just bolted them on with the pan.
Looks very original and not expensive.

I don't have the PN with me... search for Joe Lucia and oil pan. It was a post of his that suggested this.

UPDATE: It looks like Joe responded while I was typing. Bad news this pan was discontinued recently. I bought mine from Summit, so you might check the major retailers- they may have some old stock remaining.

[Justin S.]

Re: 1970 BB Oil Pan

"All Corvette big block oil pans are Corvette-only pieces and were never used for any other Chevrolet application"

Please explain the uniqueness of these pans as well as the converse of why a passenger car pan wouldn't work

[Edward C.]

Re: 1970 BB Oil Pan

"All Corvette big block oil pans are Corvette-only pieces and were never used for any other Chevrolet application"

Please explain the uniqueness of these pans as well as the converse of why a passenger car pan wouldn't work

The shape is different than other “standard” big block pans and the drain hole is in the back. On all other BBC’s the drain plug is one the side. Other pans will work as I have a 69 right now with the wrong BB in it temporarily while I build the original and it has a “standard” pan in it. I’m sure there is a reason. My first guess is the rear plug makes it easier to drain the oil.

Also, the Corvette pan was used on some Marine Mercruiser engines.

Here is a pic. Black pan is the Corvette pan. I think there are other differences in some of the other big block pans for the various other cars, applications and years but I don’t know what they are.
A92D3FBE-5531-4C2A-8CDF-704F74EA4326.jpg

[Joe L.]

Re: 1970 BB Oil Pan

"All Corvette big block oil pans are Corvette-only pieces and were never used for any other Chevrolet application"

Please explain the uniqueness of these pans as well as the converse of why a passenger car pan wouldn't work

Justin------

The Corvette oil pan is "unique" only in the sense that it was not installed on any other GM application (it's possible it was installed on marine applications as Edward mentions but those are not GM vehicle applications and are not cataloged by GM).

There were many different big block oil pans originally installed in Chevrolet vehicles including both cars and trucks. The Corvette oil pan was a 5 quart pan while most others were 4 quart. The Corvette pan had special internal baffling which included the so-called "trap door". No other big block pans included this feature.

The Corvette oil pans had a rear drain. At least one other non Corvette big block pan had a rear drain. Most were side drain, though. At least one had a bottom drain.

The Corvette pan was designed to be used with an external baffle ("windage tray"). I do not think that any other big block pan was so-designed.

The overall configuration of the Corvette pan was unique. It was not radically different than the others but it was different, in some cases subtly and in some cases extensively.

Can the Corvette oil pan be installed on other big block Chevrolet applications? Yes, it can. Can the other non-Corvette big block pans be installed on a Corvette? Yes, in most cases they can. But, they would not be "correct" and would be easily discerned.

[Mike T.]

Re: 1970 BB Oil Pan

At least a dozen years ago, maybe more like 15 or more, I ordered up a replacement Bigblock oil pan from my local Chevy Dealer Parts Department.
Not sure of what part number we used but I recently put that pan on the 427 I was building for my NOM 65 L78 Roadster and just ran across the stamped part numbers on the pan itself. Guessing that these numbers...believed to be 14095703, are not what was used as the official part number for ordering purposes but it is a 5-qt pan.
IMG_0926.jpgDSCN6059.jpg

[Joe L.]

Re: 1970 BB Oil Pan

At least a dozen years ago, maybe more like 15 or more, I ordered up a replacement Bigblock oil pan from my local Chevy Dealer Parts Department.
Not sure of what part number we used but I recently put that pan on the 427 I was building for my NOM 65 L78 Roadster and just ran across the stamped part numbers on the pan itself. Guessing that these numbers...believed to be 14095703, are not what was used as the official part number for ordering purposes but it is a 5-qt pan.
[ATTACH=CONFIG]118385[/ATTACH][ATTACH=CONFIG]118386[/ATTACH]

Mike-------


It's 14095705 and that is the actual part number of the Corvette pan supplied under GM #14091356 which SERVICES all 1965-74 Corvette big blocks. The latter is the part number for the pan UNIT which includes the14095705 pan and a GM #3967854 baffle. The 14095705 pan could not be ordered separately but the 3967854 baffle could be ordered separately. The reason the baffle was supplied with the pan is that this pan also SERVICED 1965-69 Corvette big blocks. When this pan is used with those big blocks, the existing baffle should be removed and replaced with the 3967854.

[Mike T.]

Re: 1970 BB Oil Pan

Thanks for the clarification on the part number, Joe. That new pan, that I bought some time ago, was used on the 427 I've had since the 80's and is now on the 427 I built for my 65 L78 Roadster. About a year ago, I ran across a 66 #942 4-bolt block (and 67 vintage L-88 aluminum heads) that will eventually find it's way into my 66 L72 Roadster, now running a mild but good running 396 so IDSCN5768.jpgDSCN5769.jpgDSCN5770.jpg started looking for another new GM Bigblock oil pan but obviously that didn't work out. Luckily, my neighbor who owns a 66 L72 is kinda like me in that he likes to buy 'spares' so he had an old Bigblock oil pan, the 5-quart variety, and while I couldn't spot any part numbers on that older pan, it has the same swinging trap door at the front of the baffle and he also had the windage tray. The mounting flange did need a bit of work to flatten it out but it should work just fine.