Tall deck oil pump shaft

[Craig]

OK, a friends putting together his Dart tall deck. Shop says to use the standard length oil pump drive shaft, ~6 11/16". When you use this and test fit the MSD distributor (no intake on)the distributor appears to bottom out, yet it still won't engage the notch on the top of the oil pump shaft :confused: Now if we put the intake on, I'm sure that would lift the distributor slightly and make the problem worse. If we use a long drive ~7 3/8" it appears to work OK. Just wondering if the shop was off on the application? Infomaniac, which shaft did you use on yours?

[Infomaniac]

Used a Moroso 22080. I measured it for you from the top of the installed shaft to the block inside the intake valley. On the left side of the engine it measures 3.080.
Sounds like you are trying to use a small block shaft. It will need a longer shaft if using a raised cam.
[ March 15, 2003, 02:22 PM: Message edited by: Infomaniac ]

[Craig]

The block doesn't have the raised cam. Took the oil pump, shaft and distributor and stuck it on an old 502 block, fits up fine :confused: WTF? The oil pump shaft is the same size as one that cam out of another 502. Infomaniac, that measurement is from the top of the oil pump drive shaft to block. Did you get you top measurement at the area in the lifter valley?

[RandyH]

Just a thought but MSD offers a billet unit specifically made for tall decks . It has a slip collar that allows for 1.5 inches of adjustment. :confused: My merlin didn't need it but I read about it. Good Luck,
Randy

[Craig]

Yeah, he has a slip collar one and a normal tall deck one. What's strange is we took the rear cap off of the Dart and one off of a GM. The mounting surface on the Dart is a little over 1/4" taller than the GM. This would place the oil pump that much further away from the distributor.

[RandyH]

For what its worth I just measured mine for you. Shaft lenght out to out is 6 - 11/16", shaft sticking out of the oil pump is 1-5/16", stub shaft below the Bronze gear teeth is exactly 1 inch. ALl dimensions out to out.
This is a Merlin II Standard Chevy Deck Height and Standard MSD Pro Billet. Single Plane Merline intake.
Hope is all works out for you.
Randy

[Infomaniac]

Craig:
The block doesn't have the raised cam. Took the oil pump, shaft and distributor and stuck it on an old 502 block, fits up fine :confused: WTF? The oil pump shaft is the same size as one that cam out of another 502. Infomaniac, that measurement is from the top of the oil pump drive shaft to block. Did you get you top measurement at the area in the lifter valley? Yes, I said intake valley but meant lifter valley.

[Infomaniac]

I've been there before with the small block shaft in a big block. Years ago a guy at the engine shop slid me a hardened shaft. I put it in installed the pump and pan and put it in the boat. Went to prelube the engine and the preluber would not engage the shaft. Talk about pissed off.

[Craig]

Thanks for the info guys. Man, this ones weird. I'm missing something. If we use the long shaft it engages the oil pump, but appears to ne a little too long. Now we could machine the top of the shaft down slightly and be OK, but it bugs me that what is supposed to work, won't.