Technical SBC oil pump shaft length

There are long and short pumps with different rods. Early 265-283 use a different pump than your run of the mill SBC. Maybe a mis match of parts. Ran into this with my 1957 283 when summit send me the catch all 350 style pump. Since you didn't build it you can't be sure what's in it.

 

Only the nut welded to the top of the shaft. With no weights, etc., the shaft can extend further through the housing to engage the pump drive slot.

 

The oil pump intermediate shaft length changed somewhere around 1959. The height of the oil pump drive itself may have changed around the same time too. Sounds like you have a mix and match of parts that comes out with the pump short of the distributor. I had the opposite problem years ago when I redid my 57 283 with the distributor that wouldn't fit all the way down because of a too long intermediate shaft.

 

I just checked 3 differant dist one cast iron one HEI and one alum point dist and they are all the same. Sounds like it has to be the pump drive shaft. Does the oil pan gasket look fresh? I would be thinking about pulling the pan and checking out the bearings and crank there is no way that that engine could have been running with oil pressure ever.

 

The engine, from a buddy's truck, had a miss he couldn't find, so I bought it, years ago. Found a flat cam lobe and replaced the cam, lifters and all the gaskets approx 6 yrs ago.
Had it stored until I dropped it in my 56, and now that I'm trying to get it running, things have gone downhill. If I replaced the pump drive, I don't remember, but that would be when it got a shorter shaft (SOMEHOW!)

Thanks for all the input, time to pull the shaft, I reckon.

 

I have two part numbers for the intermediate shaft. The 64-67 Nova 2 used a different shaft. Apparently it is shorter. Chevy PN3790872. Nova 2 from 1964-67 (or at least some of them) used a front sump pan and a different pump and shaft.

Standard small block shaft is Chevy PN 3998287.

At least those were the PN in the dark ages.

I learned something today, now I can go to bed!

PS, I would be very suspect of a motor that had a flat cam issue. The filings fall down on the piston skirt as it is exposed at the bottom of the stroke and cause all kinds of hell on the cylinder bore as the piston goes back up. Just ask me how I know.

 

I just did this with my shoebox. Got a free small block and never ran the number to find out the year or anything just knew it was an 80's truck motor and a small block was a small block….. no its not.

If the small block is 86 and up before the center bolt style motors, the deck height is different and it takes a longer oil pump shaft. (Your oil pan is different as well so make sure you get a gasket for the same year motor I screwed that up as well haha) Your HEI will work fine when you switch the rod to the pump out.

 

Oil pump intermediate shaft part numbers from my 64 and earlier Chevrolet parts book.

Listing is for small block Chevrolet V8.

55-57 Shaft 3836624

58-59 Shaft 3739826

59-64 Shaft 3998287

No lengths are listed. These are old numbers and are probably superseded. Any parts store worth a damned should be able to cross reference these numbers to whatever brand of engine parts they sell. Don't believe anyone when they tell you.... "oh, they're all the same".

 

Interesting. I forgot about the centre bolt versions. I was always hunting the early 70's truck blocks. I didn't realize they had different deck heights.

 

I'll wait for more proof on the differing deck heights if you don't mind.

 

you could have a pump shaft from a 64-7 nova they are 1/4" shorter as the pump set higher on the block. i put a nova pump and pan on a motor and used a stock shaft and the dist set 1/4" off the intake.

 

Any updates? The only thing I can think of is the Chevy II deal There is definately a different pump and intermediate shaft that is shorter for the front sump set up on the Chevy II's. I've never heard of the deck heights being different on the newer blocks either, I just built one using all standard SBC parts. (except the timing set which is a little different for clearance due to the roller cam provision under the timing cover and the pan because of the one piece RMS) but same intake, dist, heads, rods, pistons ETC...

 

Off topic...

A 348/409 dizzy is longer than a SBC...

pdq67

 

Why not just measure from the top of the shaft in the motor to the dist. seat on the manifold and measure that against the distributor. JW

 

I think it's the other way around Paul.

 

I just read this in one of my manuals.
55-57 use a longer shaft because the pump sits lower because of the deeper pan.

I know you said the block is not original but could somebody have put a 56 oil pump in it?

Last sentence on left. Pics a little big

 

348/409 is shorter than SBC/BBC, but the housing is larger in diameter. Hence the ability to use the latter in the former with an adapter sleeve.

 

I'm putting together a 400 sb for my '66 Nova with a Melling standard volume (M-55) pump and was wondering if it takes a 6" pump-shaft. I'm using a six qt. Milodon rear sump pan. Milodon says to use Milodon pumpshaft #23050 but it doesn't tell the length.
- 62-67 CHEVY II NOVA DEEP SUMP -
#31060
This rear sump pan is a requirement for any racing or high performance use, replacing the poorly designed stock front sump configuration. Will not work with stock power steering. High strength magnetic drain plug included.
Pan fits a 3.750" 400 stroke crank with steel stock rods. Eagle's 400" rods may need slight fitting.

Pan Capacity is 6 Quarts Plus Filter - 9 1/2" Sump Depth

Left Hand Dipstick (1955-79) 31060
Right Hand Dipstick 1980-85 & Dart SHP block, passenger side stick, 2 pc rear main 31061
Right Hand Dipstick (1986 & Up) 31062
LS Chevy - All LS series engines 31063
Oil Pump and Pick-Up Required:

Milodon 18755, (M55) 18310
Milodon 18750, (M55HV) 18313
Oil Pump Shaft 23050
Oil Pan Gasket 40100
Oil Pan Gasket, Drivers side stick, 1 piece 41000
Oil Pan Gasket, Passenger side stick, 1 piece 41001
Windage Tray - 350 Left side stick, Street / Strip, Louvered 32100
Windage Tray - 400 Left side stick, Street / Strip, Louvered 32101
Windage Tray - Right side stick, Street / Strip, Louvered 32102
Windage Tray - Race, Screen 32250
Windage Tray Install Kit 81150
Rear Pan Baffle 32500
Oil Pan Bolts, vibration resistant 85000
Oil Pan Studs, vibration resistant nuts 81300
Oil Pan Dipstick - Up to 1979, drivers side 22000
Oil Pan Dipstick - 1986 & Up, passenger side 22005

 

Does it have a Melling high volume pump? I just put one in my late 350 and it needed a different shaft.
I know it's un likely but....

 

Just found out the right one is a Melling intermedate shaft #IS55E. I'm going to use a standard volume pump

 

I believe it's 5.96" or 6" Melling makes both. This one is at O'Reillys.

Melling - Intermediate Drive Shaft
Part # IS55E
Line: MEL
Online:
Available

Store:
Available

for this item only

Add to Printable List
$8.99 Each


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Melling - Intermediate Drive Shaft
Part Number: IS55E
Line: MEL

• 1 year limited warranty
• UPC: 729295115212
• Length (In): 5.96 Inch
• Shaft Diameter (In): 0.483 Inch

Detailed Description
5.96" length by .483" round stock replacement drive shaft. Includes steel shaft guide, eliminates nylon guide. Meets or exceeds OE specifications. Made in U.S.A.



Additional Details

• Type: Round
• Material: Medium Carbon Steel
• New Or Remanufactured: New
• Heat Treated: No

 

I used a pair of 12" forceps I bought at harbor frieght today pulled it right out