Issues with swapping out 250/3speed with 350/TH400 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BigRed · 12-06-2002, 06:08 PM

Got a question for all the experts here. I currently have a '75 SWB Custom Deluxe 1/2 ton 2wd that originally had a 250/3 speed - column shift and was converted to a 350/TH400 at some time. Anyway, I will be getting another '75 that is a LWB with the same setup (250/3speed). Since the body on my truck is pretty eaten up with rust, I'm thinking of swapping my engine and Tranny out and putting them in the LWB.

Can anyone give me some info of possible issues and complications with this. As you can figure out, I already have an auto column on my current truck to put in new one and any mounts, etc. The one problem I can think of is the driveshaft. Will I be able to keep the existing drive shaft on the LWB or will I have to find a new one?

Basically, I'm trying to decide if I should replace my cab and body parts with that donor truck or would it be easier to put my engine and tranny into that truck?

Thanks for everyone's help!!!

79BIG10 · 12-07-2002, 10:34 AM

I would use the cab only and swap it over. I think it would be easier that way. Plus you could sell the truck for parts later of the donor truck. Just have to swap out vin plates to keep the titles straight. Plus you would still have a SWB which is more popular plus you wouldn't have to worry about the D/S being bad. Also no woory about the engine tranny problems coming out. Besides probably wouldn't take but a good weekend to swap the cabs over.

BigRed · 12-07-2002, 12:23 PM

Quote:

Originally posted by 79BIG10
Besides probably wouldn't take but a good weekend to swap the cabs over.

Well if that's the truth Brandon, then you're definitely invited when I do the swap!!!

For some reason, I still see it being harder to swap the cab, but then again I've never done it. Thanks for your suggestion!

Anyone else have some suggetions, thoughts?

matt67350 · 12-07-2002, 05:17 PM

I'm in NRH also, If you e-mail me your address I may be able to help or talk on Sunday. I'm off Davis Blvd. and Lola
Matthew

79BIG10 · 12-09-2002, 02:00 AM

I'm thinking that you just need to swap cabs thenthe only things that might need done then is removing cab mounts/bolts, hoses for heater/ac, column, wiper fluid hoses, tranny linkage, brake booster, distributor (take out and reinstall), electrical hook ups, speedo cable, anything else I'm forgetting guys???

low 84 · 12-09-2002, 03:27 AM

i think the whole front clip is gonna have to come off too

if i'm in town count me in

BigRed · 12-09-2002, 09:48 AM

Hey, thanks guys for your replies and support. This will probably happen after my tranny rebuild so it may be late spring or early summer. I'll definitely keep you informed!

Ryan, why do you say that about the front clip? Or, is there something I don't know about?

matt67350 · 12-09-2002, 10:59 AM

What trans are you Running?
Matthew

BigRed · 12-09-2002, 11:11 AM

I've got a TH400 (that's about to be rebuilt). The one in the donor is a 3-speed column shift.

matt67350 · 12-09-2002, 11:25 AM

I have a t350 cheap!

low 84 · 12-09-2002, 01:31 PM

i not positive, but i don['t think the cab is going to come off if you don't take the fenders off, so i guess i really didn't me the whole front clip, the grille and rad support wouldn't have to come off. i just don't see how the cab would come off with the fenders still bolted on to the truck

BigRed · 12-09-2002, 01:52 PM

Quote:

Originally posted by low 84
i not positive, but i don['t think the cab is going to come off if you don't take the fenders off, so i guess i really didn't me the whole front clip, the grille and rad support wouldn't have to come off. i just don't see how the cab would come off with the fenders still bolted on to the truck

Ok, I see what you're saying now. The fender's will definitely be replaced too so they'll be off. I'm hoping the fenders on this new truck are in good shape where I can use them too!

I'm definitely leaning towards a cab swap as I want to keep the SWB

bigblock73 · 12-09-2002, 02:03 PM

The hardest thing about the cab swap is the weight and the amout of time just un-hooking/hooking everything back up.

dont forget unhooking the E-brake cable/assembly.

The only drawback is that all the stuff you aren't going to remove from the "new" cab hopefully will work, otherwise you have to replace or swap out all that stuff too.

If it were me, I would definately keep the SWB and just swap the cab. Once you have taken off everything from the LWB...sell it or scrap it...either way you come out ahead.

I have done this before and if I wasn't up here in MN freezing my stones off I would come down and help!

-Jeff

12-06-2002, 06:08 PM	#1
BigRed Registered User Join Date: Jun 2002 Location: DFW, TX Posts: 1,680	Issues with swapping out 250/3speed with 350/TH400 Got a question for all the experts here. I currently have a '75 SWB Custom Deluxe 1/2 ton 2wd that originally had a 250/3 speed - column shift and was converted to a 350/TH400 at some time. Anyway, I will be getting another '75 that is a LWB with the same setup (250/3speed). Since the body on my truck is pretty eaten up with rust, I'm thinking of swapping my engine and Tranny out and putting them in the LWB. Can anyone give me some info of possible issues and complications with this. As you can figure out, I already have an auto column on my current truck to put in new one and any mounts, etc. The one problem I can think of is the driveshaft. Will I be able to keep the existing drive shaft on the LWB or will I have to find a new one? Basically, I'm trying to decide if I should replace my cab and body parts with that donor truck or would it be easier to put my engine and tranny into that truck? Thanks for everyone's help!!! __________________ Scott Shelbourne

12-07-2002, 10:34 AM	#2
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,775	I would use the cab only and swap it over. I think it would be easier that way. Plus you could sell the truck for parts later of the donor truck. Just have to swap out vin plates to keep the titles straight. Plus you would still have a SWB which is more popular plus you wouldn't have to worry about the D/S being bad. Also no woory about the engine tranny problems coming out. Besides probably wouldn't take but a good weekend to swap the cabs over. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

12-07-2002, 05:17 PM	#4
matt67350 Registered User Join Date: May 2001 Location: Benbrook, TX Posts: 1,060	I'm in NRH also, If you e-mail me your address I may be able to help or talk on Sunday. I'm off Davis Blvd. and Lola Matthew __________________ 69 swb stepside, rebuild and upgrade in progress

12-09-2002, 02:00 AM	#5
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,775	I'm thinking that you just need to swap cabs thenthe only things that might need done then is removing cab mounts/bolts, hoses for heater/ac, column, wiper fluid hoses, tranny linkage, brake booster, distributor (take out and reinstall), electrical hook ups, speedo cable, anything else I'm forgetting guys??? __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

12-09-2002, 03:27 AM	#6
low 84 Registered User Join Date: Jan 2002 Location: Houston, TX Posts: 2,144	i think the whole front clip is gonna have to come off too if i'm in town count me in __________________ '51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's

12-09-2002, 09:48 AM	#7
BigRed Registered User Join Date: Jun 2002 Location: DFW, TX Posts: 1,680	Hey, thanks guys for your replies and support. This will probably happen after my tranny rebuild so it may be late spring or early summer. I'll definitely keep you informed! Ryan, why do you say that about the front clip? Or, is there something I don't know about? __________________ Scott Shelbourne Last edited by BigRed; 12-09-2002 at 09:55 AM.

12-09-2002, 10:59 AM	#8
matt67350 Registered User Join Date: May 2001 Location: Benbrook, TX Posts: 1,060	What trans are you Running? Matthew __________________ 69 swb stepside, rebuild and upgrade in progress

12-09-2002, 11:11 AM	#9
BigRed Registered User Join Date: Jun 2002 Location: DFW, TX Posts: 1,680	I've got a TH400 (that's about to be rebuilt). The one in the donor is a 3-speed column shift. __________________ Scott Shelbourne

12-09-2002, 11:25 AM	#10
matt67350 Registered User Join Date: May 2001 Location: Benbrook, TX Posts: 1,060	I have a t350 cheap! __________________ 69 swb stepside, rebuild and upgrade in progress

12-09-2002, 01:31 PM	#11
low 84 Registered User Join Date: Jan 2002 Location: Houston, TX Posts: 2,144	i not positive, but i don['t think the cab is going to come off if you don't take the fenders off, so i guess i really didn't me the whole front clip, the grille and rad support wouldn't have to come off. i just don't see how the cab would come off with the fenders still bolted on to the truck __________________ '51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's

12-09-2002, 02:03 PM	#13
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	The hardest thing about the cab swap is the weight and the amout of time just un-hooking/hooking everything back up. dont forget unhooking the E-brake cable/assembly. The only drawback is that all the stuff you aren't going to remove from the "new" cab hopefully will work, otherwise you have to replace or swap out all that stuff too. If it were me, I would definately keep the SWB and just swap the cab. Once you have taken off everything from the LWB...sell it or scrap it...either way you come out ahead. I have done this before and if I wasn't up here in MN freezing my stones off I would come down and help! -Jeff



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