Leaf Spring Questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Super_Dave · 01-07-2016, 02:00 AM

On my '74 C20 project, I am going with the C20 to C10 2.5" drop spindle kit. I am removing the 14bolt rear end and swapping in a '79 12bolt. I got the '79 after the dude cut off the spring perches, so I have to order a set. My questions:

(1) If I remove some of the leaves from the C20 leaf pack and delete the overload springs, can I use the C20 springs or should I go with some C10 springs?

(2) If I go with C10 springs, are the eyes the same width and diameter? Do I have to swap out the hangers and shackles or can I keep the C20 hangers and shackles?

(3) Are there differences in the spring perches that I need to consider before ordering?

Thanks in advance.

Dave

74CustomK20 · 01-07-2016, 11:02 AM

They might not be the same legnth. You Either Have 56" Springs Or 52" Springs. Truthfully I would think taking out some c20 springs would ride better. But that's an opinion, take it as you want ya know. I'm taking out about 6 springs from my c30 pack and gonna see how that works. And in regard to width they'really both 2-1/2" wide. Same bolt size and all. All hangers the same you might just have to move the rear hanger assembly either forward-backward, or nowhere.

Super_Dave · 01-07-2016, 12:09 PM

Thanks, I think I will do exactly that... remove some leaves and the overload springs, add shorter u-bolts and spring perches to the 12 Bolt and call it good.

1970pelle · 01-08-2016, 10:26 AM

74CustomK20 is correct in that C20 main rear leaf spring is longer than the main leaf on a C10. So it would be a easier job over all staying with the C20 spring and reducing the spring pack. And replacing the hangers and shackles. Don't forget new center bolts, they will be a larger size than the C10 center bolts.

Ken

Super_Dave · 01-08-2016, 12:07 PM

Quote:

Originally Posted by 1970pelle

So it would be a easier job over all staying with the C20 spring and reducing the spring pack. And replacing the hangers and shackles. Don't forget new center bolts, they will be a larger size than the C10 center bolts.
Ken

Hi Ken,

So, if I keep the C20 leaf springs that are on the truck and remove the overload springs and a few leaves from the main pack, do I have to replace the hangers and shackles?

Replacing the bolts with new makes sense given the 42 year old age of the current bolts.

01-07-2016, 02:00 AM	#1
Super_Dave Registered User Join Date: Jul 2014 Location: Sherwood, Oregon Posts: 974	Leaf Spring Questions On my '74 C20 project, I am going with the C20 to C10 2.5" drop spindle kit. I am removing the 14bolt rear end and swapping in a '79 12bolt. I got the '79 after the dude cut off the spring perches, so I have to order a set. My questions: (1) If I remove some of the leaves from the C20 leaf pack and delete the overload springs, can I use the C20 springs or should I go with some C10 springs? (2) If I go with C10 springs, are the eyes the same width and diameter? Do I have to swap out the hangers and shackles or can I keep the C20 hangers and shackles? (3) Are there differences in the spring perches that I need to consider before ordering? Thanks in advance. Dave __________________ --Project BABA YAGA!... http://67-72chevytrucks.com/vboard/s...d.php?t=655783 --Project BABA YAGA!... http://67-72chevytrucks.com/vboard/s...ghlight=Belair "Life is tough - wear a cup!" "Old Enough to Know Better - Too Young to Resist" "Junk is something you will need three weeks after you throw it away."

01-07-2016, 11:02 AM	#2
74CustomK20 Registered User Join Date: Oct 2014 Location: Tell City, IN Posts: 637	Re: Leaf Spring Questions They might not be the same legnth. You Either Have 56" Springs Or 52" Springs. Truthfully I would think taking out some c20 springs would ride better. But that's an opinion, take it as you want ya know. I'm taking out about 6 springs from my c30 pack and gonna see how that works. And in regard to width they'really both 2-1/2" wide. Same bolt size and all. All hangers the same you might just have to move the rear hanger assembly either forward-backward, or nowhere. __________________ Big Nate Carp. Local 224. Buy made in the USA! 03 F350 6.0 Daily Race Truck. 79 C70 366 Project Dump.

01-07-2016, 12:09 PM	#3
Super_Dave Registered User Join Date: Jul 2014 Location: Sherwood, Oregon Posts: 974	Re: Leaf Spring Questions Thanks, I think I will do exactly that... remove some leaves and the overload springs, add shorter u-bolts and spring perches to the 12 Bolt and call it good. __________________ --Project BABA YAGA!... http://67-72chevytrucks.com/vboard/s...d.php?t=655783 --Project BABA YAGA!... http://67-72chevytrucks.com/vboard/s...ghlight=Belair "Life is tough - wear a cup!" "Old Enough to Know Better - Too Young to Resist" "Junk is something you will need three weeks after you throw it away."

01-08-2016, 10:26 AM	#4
1970pelle Registered User Join Date: Sep 2007 Location: N.E. Florida Posts: 500	Re: Leaf Spring Questions 74CustomK20 is correct in that C20 main rear leaf spring is longer than the main leaf on a C10. So it would be a easier job over all staying with the C20 spring and reducing the spring pack. And replacing the hangers and shackles. Don't forget new center bolts, they will be a larger size than the C10 center bolts. Ken __________________ 1985 IROC Z28 190HP TPI 305,700r4,T-tops,rear trac lock, Black on lite gray, 16in Z28 wheels 2007 Lexus ES350 (wifes) 1984 CJ7 with 1995 HO4.0L MPI, 2 1/2 OME YJ Lift “There is no limit to the amount of good you can do if you don't care who gets the credit.” ― Ronald Reagan Last edited by 1970pelle; 01-08-2016 at 10:28 AM. Reason: added more info



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