Question About Difference In Pulley Diameter? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69sixpackbee · 05-17-2002, 05:58 PM

I have a couple of 402's and both have power steering pulleys. The one in my truck now (original '72 engine) has a power steering pulley that is the same diameter as the other crank pullys. The one I am putting in (1971 engine) has a pulley that is about 1" in diameter smaller. Could this possibly be one for a higher revving engine? The pushrods in the '71 engine are 3/8" dia. and has valve springs that have inner damper coils. My orig. engine has 5/16" pushrods and single coil springs. I am curious about this. I will put my original P/S pulley on the engine I am putting in my truck and will figure out what to do with the other.

69sixpackbee · 05-20-2002, 10:03 AM

btt

Longhorn Man · 05-20-2002, 11:36 AM

If you have dual springs, there is an aftermarket (or a huge stock) cam in it. Not typical stationwagon/truck motor. The pully is probably G.M.'s way of cutting costs and using a 'universal" pully that fits 5 models instead of one part number per model.
Just a guess on the pully, but it makes sence.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
E-mail longhornmail@yahoo.com
My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough?
Columbus Ohio

CraigS · 05-20-2002, 03:01 PM

Both of the 454s that I had for my truck came stock with dual springs. Granted, they weren't stock motors for the truck, but I don't think it was uncommon for big block GMs to have dual springs. Both had 5/16 hardened pushrods and guideplates.

05-17-2002, 05:58 PM	#1
69sixpackbee Registered User Join Date: Jan 2001 Location: Sabinal, Texas Posts: 1,706	Question About Difference In Pulley Diameter? I have a couple of 402's and both have power steering pulleys. The one in my truck now (original '72 engine) has a power steering pulley that is the same diameter as the other crank pullys. The one I am putting in (1971 engine) has a pulley that is about 1" in diameter smaller. Could this possibly be one for a higher revving engine? The pushrods in the '71 engine are 3/8" dia. and has valve springs that have inner damper coils. My orig. engine has 5/16" pushrods and single coil springs. I am curious about this. I will put my original P/S pulley on the engine I am putting in my truck and will figure out what to do with the other.

05-20-2002, 03:01 PM	#4
CraigS Registered User Join Date: Dec 2000 Location: Gresham, OR, USA Posts: 106	Both of the 454s that I had for my truck came stock with dual springs. Granted, they weren't stock motors for the truck, but I don't think it was uncommon for big block GMs to have dual springs. Both had 5/16 hardened pushrods and guideplates. __________________ 72 GMC K20, 454, TH350 00 GMC Yukon 66 Ford Bronco

05-20-2002, 10:03 AM	#2
69sixpackbee Registered User Join Date: Jan 2001 Location: Sabinal, Texas Posts: 1,706	btt

05-20-2002, 11:36 AM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	If you have dual springs, there is an aftermarket (or a huge stock) cam in it. Not typical stationwagon/truck motor. The pully is probably G.M.'s way of cutting costs and using a 'universal" pully that fits 5 models instead of one part number per model. Just a guess on the pully, but it makes sence. ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite. E-mail longhornmail@yahoo.com My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough? Columbus Ohio



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.