The Long and Short of it - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**1970 CST Short Wide** · 06-03-2002, 10:18 AM

What determinds the use of a Long or Short water pump on a big block convertion. I have 72 motor mounts so what pump would I use.

Pont · 06-03-2002, 10:35 AM

I would think you can use long or short. I have a big block in mine that originally had a short water pump but now has a long water pump. Just make sure you have radiator clearance for the long water pump. It's easier to get brackets and pulleys for the long water pump if that matters to you.

tom hand · 06-03-2002, 11:01 AM

Short was original,so use short if that is important. Long is off 73 up,but is much easier to find and actally better,IMO. On both the big block and the small block when they went to the long water pump they moved all the accessorys in closer,so the setup uses shorter belts,which is much better if you want to build a high reving motor. A long water pump setup works best if you set the motor back about 1.5 inches on a 2WD but you can make it work without doing that.

bouncytruck · 06-03-2002, 11:30 AM

I have a small block with a short on it. I'd like to convert it over to a long when the pump goes out. The belt to the alternator is much longer and slips easier on the short pump than on the long.

**1970 CST Short Wide** · 06-03-2002, 02:36 PM

Tom
If I set the motor back 1 1/2 inches then I have to move trans mount and cut driveshaft RIGHT? If I dont move it back what problems do I run into?

Thanks for the info
Steve

tom hand · 06-03-2002, 03:17 PM

If you don't move the motor back a stock clutch fan will be very close to the radiator [or actally hit the radiator depending on what thickness radiator you are running] and the fan will be too far in the shroud. So you can use a flex fan with a shorter spacer,[which I do not recommend,they have been know to come apart] or switch to an eletric fan. Moveing the motor back works best and looks completly stock when finished IMO.

06-03-2002, 10:18 AM	#1
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,185	The Long and Short of it What determinds the use of a Long or Short water pump on a big block convertion. I have 72 motor mounts so what pump would I use. __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

06-03-2002, 10:35 AM	#2
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	I would think you can use long or short. I have a big block in mine that originally had a short water pump but now has a long water pump. Just make sure you have radiator clearance for the long water pump. It's easier to get brackets and pulleys for the long water pump if that matters to you. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

06-03-2002, 11:01 AM	#3
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Short was original,so use short if that is important. Long is off 73 up,but is much easier to find and actally better,IMO. On both the big block and the small block when they went to the long water pump they moved all the accessorys in closer,so the setup uses shorter belts,which is much better if you want to build a high reving motor. A long water pump setup works best if you set the motor back about 1.5 inches on a 2WD but you can make it work without doing that. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

06-03-2002, 11:30 AM	#4
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,038	I have a small block with a short on it. I'd like to convert it over to a long when the pump goes out. The belt to the alternator is much longer and slips easier on the short pump than on the long. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

06-03-2002, 02:36 PM	#5
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,185	Tom If I set the motor back 1 1/2 inches then I have to move trans mount and cut driveshaft RIGHT? If I dont move it back what problems do I run into? Thanks for the info Steve __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

06-03-2002, 03:17 PM	#6
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	If you don't move the motor back a stock clutch fan will be very close to the radiator [or actally hit the radiator depending on what thickness radiator you are running] and the fan will be too far in the shroud. So you can use a flex fan with a shorter spacer,[which I do not recommend,they have been know to come apart] or switch to an eletric fan. Moveing the motor back works best and looks completly stock when finished IMO. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS



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