Need opinions on 66 Chevy 3/4 frame disc swap questions... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMCMG · 01-31-2010, 12:19 AM

I have read every FAQ and thread I can find, and still don't have enough information to answer these questions without input from people who know better.

A brief summary of my build to add context to my question: I am building a 64 GMC 1/2 ton LWB on a 66 Chevy 3/4 ton frame, so I have trailing arms for the air ride setup. I have a 62 GMC donor truck that was converted by the PO to front discs/5 lugs using front parts/rear axle from a 78. I want to convert the 66 3/4 ton frame to disc/5 lug using parts from the 62 (which is at this time a complete truck). I want to make this as easy as possible/do it right, keeping in mind that I will be working around body/engine on the 62.

Questions: should I swap the entire front cross member, or parts? If just parts, which ones? If the entire cross member, does anyone have any good suggestions for easy ways to get to the crossmember bolts without taking everything apart? I don't mind pulling the engine out of the 62 - I have a friend that wants it anyway. Any other bright ideas/something I might not have thought of/etc. would be appreciated. This is my first attempt at something like this, and I don't want to screw it up or generate more work for myself than I have to. Any and all input is greatly appreciated. Thanks!

ruffrida2005 · 01-31-2010, 02:14 AM

I would just unbolt the control arms and swap them over, dont take the spindle or brakes off. Much easier then swapping the crossmembers. Since the crossmembers from 63-87 are the same you dont need to swap them.

**Captainfab** · 01-31-2010, 02:27 AM

With one exception....I would seperate the control arms from the spindles, and leave the spindles, rotors and calipers together. All together they are way to awkward to handle. Also I would recommend upgrading to the larger lower control arm u-bolts on the '78 disc assembly.

If you need adapters for the power steering or power brakes let me know.

**Chevy Fleetside** · 01-31-2010, 10:06 AM

3/4 ton crossmembers are differnt. The lower control arms bolt up with 4 bolts not two U bolts. At least they did on Highlanders truck. I have a 66 3/4 ton and I think is also has 4 bolts and not the 2 U bolts. The later model 3/4 ton crossmembers use U bolts. http://67-72chevytrucks.com/vboard/s...d.php?t=357610

GMCMG · 01-31-2010, 10:53 AM

Quote:

Originally Posted by Chevy Fleetside

3/4 ton crossmembers are differnt.

So are you saying I should swap the whole crossmember?

**Chevy Fleetside** · 01-31-2010, 11:47 AM

Look and see how the lower control arms are bolted up. They they are using 4 regular bolts then the 1/2 ton control arms will not work as they used U bolts. If that is the case then you probably will have to swap out the crossmembers. I am going to put 1/2 ton suspension in my 3/4 ton and will be swapping out the whole crossmember. If you look through that thread I posted a link for we do point out the holes that need to be drilled. The 66 perches should just bolt right up to the newer crossemember also.

GMCMG · 01-31-2010, 09:47 PM

You were right; 4 bolts instead of U-bolts. Turned out it was pretty easy just pulling the whole crossmember! Plus, I lucked out. Found a guy about 3 hours from here with a 82 1/2 ton chassis for cheap. Going to pick it up this next weekend, and that way I won't have to tear apart the 62 (hated to anyway). Well, here's the frame:

jason65 · 01-31-2010, 10:01 PM

The cross shafts on the lower control arms will swap out. I have 1/2 ton lower control arms on 3/4 ton cross shafts. You just need to make sure there clocked right. But the new crossmember is a better way to go I think. Some say the older control arm bushings have less deflection that the 80s style.

**Chevy Fleetside** · 01-31-2010, 10:09 PM

ahhhh memories...

jason65 · 01-31-2010, 10:11 PM

Yep. Makes you want to do it all over again. But on your other truck.

**Chevy Fleetside** · 01-31-2010, 11:01 PM

I wouldn't mind but it takes to much time and money. I am going to get it on the road and use it for pleasure and work.

**Chevy Fleetside** · 01-31-2010, 11:03 PM

and one more.. OH geez. I just relized I hijacked the thread. Sorry dude...

ruffrida2005 · 01-31-2010, 11:07 PM

well that's good to know about the 4 bolts on the lower control arms. Learn something new every day.

**Captainfab** · 02-01-2010, 02:25 AM

Yes the older C20's had bolts on the LCA shafts, I wasn't thinking about that when I posted. It may be better to change the crossmember since the saddles for the LCA shafts won't be there on the C20 crossmember.

GMCMG · 02-01-2010, 08:42 PM

Quote:

Originally Posted by Chevy Fleetside

ahhhh memories...

Maaannnnnnn, I can't wait until my frame has some paint and a motor...

BTW, thanks to everyone for information/comments/suggestions/input!

01-31-2010, 12:19 AM	#1
GMCMG Registered User Join Date: Nov 2009 Location: Center, MO Posts: 121	Need opinions on 66 Chevy 3/4 frame disc swap questions... I have read every FAQ and thread I can find, and still don't have enough information to answer these questions without input from people who know better. A brief summary of my build to add context to my question: I am building a 64 GMC 1/2 ton LWB on a 66 Chevy 3/4 ton frame, so I have trailing arms for the air ride setup. I have a 62 GMC donor truck that was converted by the PO to front discs/5 lugs using front parts/rear axle from a 78. I want to convert the 66 3/4 ton frame to disc/5 lug using parts from the 62 (which is at this time a complete truck). I want to make this as easy as possible/do it right, keeping in mind that I will be working around body/engine on the 62. Questions: should I swap the entire front cross member, or parts? If just parts, which ones? If the entire cross member, does anyone have any good suggestions for easy ways to get to the crossmember bolts without taking everything apart? I don't mind pulling the engine out of the 62 - I have a friend that wants it anyway. Any other bright ideas/something I might not have thought of/etc. would be appreciated. This is my first attempt at something like this, and I don't want to screw it up or generate more work for myself than I have to. Any and all input is greatly appreciated. Thanks! __________________ GMCMG 1964 GMC 1/2 ton LWB project - 1982 GMC 6.2 diesel engine/suspension donor - 1966 Chevy 3/4 ton frame/doors/fenders donor - tons of parts - cause you can't build a truck without 4 of everything! 2001 3/4HD Duramax Diesel extended cab lwb4x4 1984 Chevy C30 6.2 diesel lift truck (project) 1962 GMC w/5 lugs, 350/350 auto (was for parts, but couldn't bring myself to do it!) glascock.m@hotmail.com

01-31-2010, 02:14 AM	#2
ruffrida2005 Member of the longbed union. Join Date: Feb 2009 Location: Killeen, Tx Posts: 2,158	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... I would just unbolt the control arms and swap them over, dont take the spindle or brakes off. Much easier then swapping the crossmembers. Since the crossmembers from 63-87 are the same you dont need to swap them. __________________ Paul 88 GMC Crew Cab dually, 454/T400 64 LWB 400 HP 350/350T Bagged, under construction! Sold most of it! 92 S10 Iron Duke 5 speed, 5/7 drop for now. soon to be bagged. Sold http://67-72chevytrucks.com/vboard/s...59#post4637759

01-31-2010, 02:27 AM	#3
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... With one exception....I would seperate the control arms from the spindles, and leave the spindles, rotors and calipers together. All together they are way to awkward to handle. Also I would recommend upgrading to the larger lower control arm u-bolts on the '78 disc assembly. If you need adapters for the power steering or power brakes let me know. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

01-31-2010, 10:06 AM	#4
Chevy Fleetside Registered User Join Date: Sep 2006 Location: San Francisco Posts: 4,782	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... 3/4 ton crossmembers are differnt. The lower control arms bolt up with 4 bolts not two U bolts. At least they did on Highlanders truck. I have a 66 3/4 ton and I think is also has 4 bolts and not the 2 U bolts. The later model 3/4 ton crossmembers use U bolts. http://67-72chevytrucks.com/vboard/s...d.php?t=357610 __________________ "A man and his truck, what a beautiful thing" 65 Short Fleetside BBC 65 Long Fleetside 283 3 on the tree for now. my build thread http://www.67-72chevytrucks.com/vboa...d.php?t=259536 Last edited by Chevy Fleetside; 01-31-2010 at 10:21 AM.

01-31-2010, 11:47 AM	#6
Chevy Fleetside Registered User Join Date: Sep 2006 Location: San Francisco Posts: 4,782	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... Look and see how the lower control arms are bolted up. They they are using 4 regular bolts then the 1/2 ton control arms will not work as they used U bolts. If that is the case then you probably will have to swap out the crossmembers. I am going to put 1/2 ton suspension in my 3/4 ton and will be swapping out the whole crossmember. If you look through that thread I posted a link for we do point out the holes that need to be drilled. The 66 perches should just bolt right up to the newer crossemember also. __________________ "A man and his truck, what a beautiful thing" 65 Short Fleetside BBC 65 Long Fleetside 283 3 on the tree for now. my build thread http://www.67-72chevytrucks.com/vboa...d.php?t=259536

01-31-2010, 09:47 PM	#7
GMCMG Registered User Join Date: Nov 2009 Location: Center, MO Posts: 121	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... You were right; 4 bolts instead of U-bolts. Turned out it was pretty easy just pulling the whole crossmember! Plus, I lucked out. Found a guy about 3 hours from here with a 82 1/2 ton chassis for cheap. Going to pick it up this next weekend, and that way I won't have to tear apart the 62 (hated to anyway). Well, here's the frame: Attached Images __________________ GMCMG 1964 GMC 1/2 ton LWB project - 1982 GMC 6.2 diesel engine/suspension donor - 1966 Chevy 3/4 ton frame/doors/fenders donor - tons of parts - cause you can't build a truck without 4 of everything! 2001 3/4HD Duramax Diesel extended cab lwb4x4 1984 Chevy C30 6.2 diesel lift truck (project) 1962 GMC w/5 lugs, 350/350 auto (was for parts, but couldn't bring myself to do it!) glascock.m@hotmail.com

01-31-2010, 10:01 PM	#8
jason65 Registerd User Join Date: Sep 2008 Location: Oklahoma Posts: 2,118	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... The cross shafts on the lower control arms will swap out. I have 1/2 ton lower control arms on 3/4 ton cross shafts. You just need to make sure there clocked right. But the new crossmember is a better way to go I think. Some say the older control arm bushings have less deflection that the 80s style. Last edited by jason65; 01-31-2010 at 10:04 PM.

01-31-2010, 10:09 PM	#9
Chevy Fleetside Registered User Join Date: Sep 2006 Location: San Francisco Posts: 4,782	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... ahhhh memories... Attached Images __________________ "A man and his truck, what a beautiful thing" 65 Short Fleetside BBC 65 Long Fleetside 283 3 on the tree for now. my build thread http://www.67-72chevytrucks.com/vboa...d.php?t=259536

01-31-2010, 10:11 PM	#10
jason65 Registerd User Join Date: Sep 2008 Location: Oklahoma Posts: 2,118	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... Yep. Makes you want to do it all over again. But on your other truck.

01-31-2010, 11:01 PM	#11
Chevy Fleetside Registered User Join Date: Sep 2006 Location: San Francisco Posts: 4,782	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... I wouldn't mind but it takes to much time and money. I am going to get it on the road and use it for pleasure and work. __________________ "A man and his truck, what a beautiful thing" 65 Short Fleetside BBC 65 Long Fleetside 283 3 on the tree for now. my build thread http://www.67-72chevytrucks.com/vboa...d.php?t=259536

01-31-2010, 11:03 PM	#12
Chevy Fleetside Registered User Join Date: Sep 2006 Location: San Francisco Posts: 4,782	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... and one more.. OH geez. I just relized I hijacked the thread. Sorry dude... Attached Images __________________ "A man and his truck, what a beautiful thing" 65 Short Fleetside BBC 65 Long Fleetside 283 3 on the tree for now. my build thread http://www.67-72chevytrucks.com/vboa...d.php?t=259536 Last edited by Chevy Fleetside; 01-31-2010 at 11:05 PM.

01-31-2010, 11:07 PM	#13
ruffrida2005 Member of the longbed union. Join Date: Feb 2009 Location: Killeen, Tx Posts: 2,158	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... well that's good to know about the 4 bolts on the lower control arms. Learn something new every day. __________________ Paul 88 GMC Crew Cab dually, 454/T400 64 LWB 400 HP 350/350T Bagged, under construction! Sold most of it! 92 S10 Iron Duke 5 speed, 5/7 drop for now. soon to be bagged. Sold http://67-72chevytrucks.com/vboard/s...59#post4637759

02-01-2010, 02:25 AM	#14
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Need opinions on 66 Chevy 3/4 frame disc swap questions... Yes the older C20's had bolts on the LCA shafts, I wasn't thinking about that when I posted. It may be better to change the crossmember since the saddles for the LCA shafts won't be there on the C20 crossmember. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE Last edited by Captainfab; 02-01-2010 at 02:29 AM.



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