More weird swap questions..... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

qksilver · 02-06-2007, 12:28 AM

Bought a 68 c-30 wrecker 2 months ago for 4 bills. You can imagine what condition it's in for that price.
I have all the sheet metal to get it back to good shape but have questions about mechanical stuff.
The truck orginally came with a 6 so the rear has really deep gears, thought about a 5 speed swap but don't have the money.
Found a complete C-40 truck cheap with a good running 350, 4 speed and a 2 speed rear. Frame and body are wasted but good running gear.
Question is can I install the C-40 rear under my C-30. It has the dually option so the wheels stick out past the body and the wrecker bed has fenders.
So width sin't a problem, I can trim the fenders if I need but are the spring perch widths the same the same on the rears and is it possible to fit 16 on the C-40 rear or can I use the C-40 wheels on my C-30.

I am not able to go to the C-40 and measure stuff for many medical reasons and if I don't buy the truck it is going to scrap.
Any help would be apreciated
Thanks,
Steve

qksilver · 02-06-2007, 10:28 AM

Ttt

**special-K** · 02-06-2007, 02:02 PM

I can`t say for sure,but I believe the rear will swap.Is it 5 or 8-lug?There were the heavy wide 5-lug 1 tons in a light truck body.Then,there were C/40s in the medium-duty body

*72lb4x4* · 02-06-2007, 02:35 PM

I think a bit of net research will show that the big truck 2 speed rear ends had lower gears than a C30 wrecker.

qksilver · 02-06-2007, 10:52 PM

..........what can i say, I was being lazy

*72lb4x4* · 02-06-2007, 11:19 PM

Come to think of it, I have a book that says that 2 speed rear ends are 6.10:1 and 8.10:1. I can't say if they all are, but it seems some were anyway.

jeffspower · 02-06-2007, 11:48 PM

IIRC, the GM 2 speed rears had 6.60/8.83 ratios. Your C30 probably has 5.13's or 4.57's. You can find 4.10's & swap the pumpkin easy enough.

rwgregory · 02-07-2007, 03:43 AM

I don't know what year your C-40 is but the rear gears are still probably too deep. According to the GM factory overhaul manual, October 1968 edition the gear ratios for the Corporation T150 2-spd. rear axle are 5.83:1 & 7.95:1.

qksilver · 02-07-2007, 03:55 AM

I was thinking with the larger diameter wheels it would work. It's a 71
My wrecker only has a Holmes 400 on it. If it had a 500 or up I would use the wrecker bed on the C-40 and part the 68 out.
I am thinking about getting the C-40 anyway and down the road make it into a roll back. I can get it really cheap

**special-K** · 02-07-2007, 08:00 AM

Get it.They stopped making these trucks only to bring them back more recently.What year is it?I know a guy with a`66 C/40 that is built off the light truck platform(10-30).I`ve seen the HD C/30 in 67-72s that have the wide-5 lug pattern and 19.5 rims.I`ve een 67-72 C/40s that are built on the medium-duty platform.

02-06-2007, 12:28 AM	#1
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	More weird swap questions..... Bought a 68 c-30 wrecker 2 months ago for 4 bills. You can imagine what condition it's in for that price. I have all the sheet metal to get it back to good shape but have questions about mechanical stuff. The truck orginally came with a 6 so the rear has really deep gears, thought about a 5 speed swap but don't have the money. Found a complete C-40 truck cheap with a good running 350, 4 speed and a 2 speed rear. Frame and body are wasted but good running gear. Question is can I install the C-40 rear under my C-30. It has the dually option so the wheels stick out past the body and the wrecker bed has fenders. So width sin't a problem, I can trim the fenders if I need but are the spring perch widths the same the same on the rears and is it possible to fit 16 on the C-40 rear or can I use the C-40 wheels on my C-30. I am not able to go to the C-40 and measure stuff for many medical reasons and if I don't buy the truck it is going to scrap. Any help would be apreciated Thanks, Steve

02-06-2007, 10:28 AM	#2
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: More weird swap questions..... Ttt

02-06-2007, 02:02 PM	#3
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,859	Re: More weird swap questions..... I can`t say for sure,but I believe the rear will swap.Is it 5 or 8-lug?There were the heavy wide 5-lug 1 tons in a light truck body.Then,there were C/40s in the medium-duty body __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

02-06-2007, 02:35 PM	#4
72lb4x4 Account Suspended Join Date: Jul 2006 Location: DFW Posts: 1,427	Re: More weird swap questions..... I think a bit of net research will show that the big truck 2 speed rear ends had lower gears than a C30 wrecker.

02-06-2007, 10:52 PM	#5
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: More weird swap questions..... ..........what can i say, I was being lazy

02-06-2007, 11:19 PM	#6
72lb4x4 Account Suspended Join Date: Jul 2006 Location: DFW Posts: 1,427	Re: More weird swap questions..... Come to think of it, I have a book that says that 2 speed rear ends are 6.10:1 and 8.10:1. I can't say if they all are, but it seems some were anyway.

02-06-2007, 11:48 PM	#7
jeffspower Well, Whoop-dee-do! Join Date: Mar 2003 Location: Easton, Mo. pop.- me & scarcely a few others Posts: 2,302	Re: More weird swap questions..... IIRC, the GM 2 speed rears had 6.60/8.83 ratios. Your C30 probably has 5.13's or 4.57's. You can find 4.10's & swap the pumpkin easy enough. __________________ '68 GMC shortbox 4x4 350/SM465/T221- bought it in '83 SOLD '72 K20 500 Cad/TH400/NP205 SOLD '92 Chevy 2500 6.5 mech TD 4L80E crusty daily driver '72 Monte Carlo... sweet low mile toy '11 Dodge Challenger IE 392 6spd... midlife car

02-07-2007, 03:43 AM	#8
rwgregory Registered User Join Date: Apr 2005 Location: Chula Vista, California Posts: 495	Re: More weird swap questions..... I don't know what year your C-40 is but the rear gears are still probably too deep. According to the GM factory overhaul manual, October 1968 edition the gear ratios for the Corporation T150 2-spd. rear axle are 5.83:1 & 7.95:1. __________________ rwgregory 67 GMC 2500 ,2w/d wide box 305 V-6, 4-speed

02-07-2007, 03:55 AM	#9
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: More weird swap questions..... I was thinking with the larger diameter wheels it would work. It's a 71 My wrecker only has a Holmes 400 on it. If it had a 500 or up I would use the wrecker bed on the C-40 and part the 68 out. I am thinking about getting the C-40 anyway and down the road make it into a roll back. I can get it really cheap

02-07-2007, 08:00 AM	#10
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,859	Re: More weird swap questions..... Get it.They stopped making these trucks only to bring them back more recently.What year is it?I know a guy with a`66 C/40 that is built off the light truck platform(10-30).I`ve seen the HD C/30 in 67-72s that have the wide-5 lug pattern and 19.5 rims.I`ve een 67-72 C/40s that are built on the medium-duty platform. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~



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