What are the adavantages to a 6 bolt pump compared to a 5 bolt? Was there a certain application of the 6 bolt pumps?

i'm assuming you mean the oil pump i think the 6 bolt is the original pump and any new replacement will have 5 bolts i don't think their is any difference in them I might be wrong tho.

In today's catalogs, a "6 hole" is the OEM oil pump with 5/8 impeller thickness. "5 hole" are the aftermarket pumps with the 7/8 thick impeller.

In the past, other manufacturers had 5 & 6 bolt hole pumps with any of the 3 impeller thicknesses so it is always good to measure before ordering a oil pump rebuild kit.
DD

Thanks

Besides the prevously mentioned differences, here is another.

Despite my best efforts when replacing a 6 bolt with a five, I had an oil leak at the place where the 6th hole was omitted. I didn't want to RTV it to death, and didn't want to overtorque the bolts. So I just marked the missing hole center on the pump body by placing a gasket on the back, then drilled the hole (using a drill press ) and created a 6 bolt pump. Worked like a charm, leak stopped at FSM torque.

rock
'64d100

Thanks for the info and tips.

Bernie Kuschel and Doc describe an oil pump gear oiling system using a modified 6-bolt pump
HERE

_________________
"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

Is there a good source for 6-hole pumps?

_________________
"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

I think all the aftermarket suppliers have now moved to the 5 hole version.
There are "NOS" 6 hole pumps still out there, start looking at suppliers that don't sell SL6 oil pumps that often.
These show up on ebag, there is one listed now at this link

As noted before, many of the early SL6 OEM pumps were 6 hole units and rebuild kits are available.
DD