oil pump ------- what is it?

[Gene M.]

Small block oil pump with casting # GM3732798 and the screws securing the cap are metric otherwise it looks normal.

I removed the spring it is .041" wire diameter and is 2.150" long. The metric screws throws me, what is it for?

[Pat H.]

Re: oil pump ------- what is it?

Gene,
I was just looking for the thread I read last night about the high pressure in current aftermarket oil pumps. I have one of these on the bench and I believe it came out of a 69 350-300 Corvette. I was in a box with rockers, stub and valve seals. Since I have the high pressure issue with my 59, I was wondering if the unit would just bolt up rather than changing springs. I never checked the screws. The based on the oil pump, where the screws are has a part # 3704180 and in that casting it says GM85

[Joe L.]

Re: oil pump ------- what is it?

Small block oil pump with casting # GM3732798 and the screws securing the cap are metric otherwise it looks normal.

I removed the spring it is .041" wire diameter and is 2.150" long. The metric screws throws me, what is it for?

Gene-------

I think the casting number is actually 3832788. In any event, this was the casting number used for small block oil pumps from at least 1959 through the 1990's. It was used for finished pumps #3764547 and 3821979 plus several others. It is a standard volume pump. The 3764547 both preceded and succeeded the 3821979 and was manufactured by GM well into the 90's. At some point in the history of the 3764547 the cover screws were converted to metric. I don't know exactly when this occurred but I think it was sometime in the early to mid 80's. After that time, the 3764547 pumps used in PRODUCTION and sold in SERVICE had the metric screws.

[Joe L.]

Re: oil pump ------- what is it?

Gene,
I was just looking for the thread I read last night about the high pressure in current aftermarket oil pumps. I have one of these on the bench and I believe it came out of a 69 350-300 Corvette. I was in a box with rockers, stub and valve seals. Since I have the high pressure issue with my 59, I was wondering if the unit would just bolt up rather than changing springs. I never checked the screws. The based on the oil pump, where the screws are has a part # 3704180 and in that casting it says GM85

Pat-------


If the pump has SLOTTED HEAD screws, they will NOT be metric. If it's an original 1969 pump, they should be slotted head.

[Gene M.]

Re: oil pump ------- what is it?

Joe,
Thanks for reply. I looked close at casting number and it is definitely GM3732796. There is a photo Mike Eby took in the other post "melling oil pump correct spring" it is post #21 that is the same exact casting. Is this pump (GM3732796) also a correct production Corvette SB casting?

[Joe L.]

Re: oil pump ------- what is it?

Joe,
Thanks for reply. I looked close at casting number and it is definitely GM3732796. There is a photo Mike Eby took in the other post "melling oil pump correct spring" it is post #21 that is the same exact casting. Is this pump (GM3732796) also a correct production Corvette SB casting?

Gene-------


Well, regardless of whether the last two digits are 96 or 88, I'm sure we're talking about the same casting. 9,6,8 and 3 can be extremely difficult to differentiate on many castings. I'm virtually certain there were never main body castings for small block oil pumps that began with 37327 ended in both 88 and 96. This kind of casting number confusion crops up all the time. I'll check more on this, though, when I get home next week.

[Gene M.]

Re: oil pump ------- what is it?

Gene-------


Well, regardless of whether the last two digits are 96 or 88, I'm sure we're talking about the same casting. 9,6,8 and 3 can be extremely difficult to differentiate on many castings. I'm virtually certain there were never main body castings for small block oil pumps that began with 37327 ended in both 88 and 96. This kind of casting number confusion crops up all the time. I'll check more on this, though, when I get home next week.

Joe,
Thanks for any efforts to decipher this casting. Check out the photo in Mike Eby post #21 "melling oil pump correct spring" is very clear to read casting number GM3732796 and the same as mine.

[Joe L.]

Re: oil pump ------- what is it?

Joe,
Thanks for any efforts to decipher this casting. Check out the photo in Mike Eby post #21 "melling oil pump correct spring" is very clear to read casting number GM3732796 and the same as mine.

Gene------


Yes, you're correct. The casting number is 3732796. I don't know how I came up with that 3732788. In fact, I've reported the number previously as 3732796. I have an NOS GM #3821979 oil pump (used for most 63-73 small blocks). The one I have was manufactured about 1965. I'll double check it when I get home.