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09-27-2017, 08:50 PM | #1 |
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Ditching th350 for sm465 questions, maybe GV OD
I have a 71 long bed with a 350 sbc and th350. The trans is tired and I'd rather have a manual in the truck anyways. The low geared manuals have interested me for a while but I haven't been able to find a decent one for sale locally until recently.
Found a guy selling an sm465 with most of what I need for the swap except the high hump and clutch pedal. The 465 came out of a 72 c20. Parts seller has listed: Bell housing, the clutch, pressure plate, splash shields, shifter, manual transmission cross member and all the original clutch brackets and linkages. My driving usage is: I haul loads locally for house projects (Lumber, soil, etc), and cruising locally. Due to where I live, it does see the highway some, so I think it's good that I have a 3.08 rear. Now for the questions...
Thanks for any of your input. Project started out straightforward then is now appearing to be much more than anticipated.
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71 Long bed C10 w/68 front clip, 350 SBC+HEI, TH350 06 Yukon XL Denali - Stock |
09-27-2017, 09:30 PM | #2 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
I have a nice hi hump if you need one, pm me
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09-27-2017, 10:24 PM | #3 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
I've got almost the exact setup you have, except I'm using 73+ engine mounts. I think that the driveshaft will be the least of your trouble with what you're trying to do.
My truck was born with an SM465, and the z-bar bracket and trans crossmember stubs are still there. If I put a 465 back in, NOTHING would line up due to the engine setback. If you want to use all the original linkage and crossmember, you'll need to move the engine back to the forward position. Drilling the holes for the bracket and crossmember will require an angle drill, short bit, contortions, and lots of cussing. Or cab removal. If you want to keep the engine setback ( better handling ) you'd want to consider a hydraulic clutch along with a 73+ SM465 ( with rear mount ) and an auto trans crossmember. I'm going hydraulic when I put a manual back in. As far as the driveshaft, grab the C20 part. You can get conversion u-joints to match the shaft and diff yoke. It will also be long enough to shorten to whatever length you need. Sorry for the looooong post. |
09-28-2017, 09:31 AM | #4 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
Long posts are ok. Gives me more info!
I am ok with moving the engine forward if I have to mess with the drive shaft anyways. When I did the motor swap, I had to move the auto trans cross member forward a 1/2", so I had to drill the frame. I dont have an angle drill, so I assume it was ok with the drills and bits I have on hand. The can is staying on. The truck is a driver now, and hoping to do the swap in less than a month (or maybe two) worth of weekends. Anything longer and the wife will get annoyed with it taking a spot in the driveway. Ball park, about how much is it to do the driveshaft work I am looking at needing? I have no idea if it is $200 or $2000.
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71 Long bed C10 w/68 front clip, 350 SBC+HEI, TH350 06 Yukon XL Denali - Stock |
09-28-2017, 09:33 AM | #5 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
Here are the photos I have so far. Plan to see it and whatever else I can get my hands on this Sunday and take some measurements.
Anything stand out that I should take note of?
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71 Long bed C10 w/68 front clip, 350 SBC+HEI, TH350 06 Yukon XL Denali - Stock |
09-28-2017, 01:08 PM | #6 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
if you don't put a clutch kit in it while its apart you,ll regret it
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09-28-2017, 09:28 PM | #7 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
If you're stuck on the 465 you will be better off to get everything you can from the seller. I don't think I would ever do one though. The NV4500 would net you OD and a manual that is far better suited to anything less than a heavy hauler. Just my opinion mind you. If you're going to be doing a driveshaft and all, you might as well get the OD for your trouble.
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The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" |
09-29-2017, 07:51 AM | #8 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
to answer your questions:
1- you want a specialized driveline shop. in our area there are several driveshaft only shops 2- can't answer but Id leave it where it is. 3- fixed yoke means you bolt the u joint to the trans, not slide the shaft in. you need to get the 2 piece off him so you have some movement in the driveshaft for suspension travel 4- get the shaft 5- no there is nothing with the rear end to stop you from using the driveshaft 6- forget the GV. if you want OD look for an NV4500. my .02 unless the Gv unit was absolutely dirt cheap, you will have way more into it than finding an nv4500. I would swap the sm465 now, then if you want OD start looking for a NV4500 and swap it in later. |
09-29-2017, 10:36 AM | #9 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
Thanks. I've decided on dropping the GV idea. It was a long shot anyways.
Also will try to get the shaft. Talked to a shop and they told me I'd be better off with the c20 shaft if it's longer. An NV would be nice, but the cheapest I've been finding them around here is more than 7x as much and is just the trans. I'd be 10x or more into it after all was said and done. One day it will make sense, but not for where I'm at now. It does not see a lot of miles. I am just waiting on a pic of the high hump from bcowan and a couple guys to get back to me on the pedal. Ratty has me a little worried on doing the linkage, but I'm sure I can figure it out eventually. Or I'll be asking more questions if I can't find the info on here in other threads.
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71 Long bed C10 w/68 front clip, 350 SBC+HEI, TH350 06 Yukon XL Denali - Stock |
09-29-2017, 12:37 PM | #10 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
hump pics coming tonight
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09-29-2017, 07:06 PM | #11 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
I did exactly what you are doing, 350 to 465. I found a member on here parting a truck and got everything from the steering coiumn to clutch linkage to drive shaft. It worked out really well and I still have 3.08 posy rear end with a 350 powering everything with no issues. The truck with 235/75-15s will run down the interstate at about 2700rpm @70mph.
All that being said I am swapping in an NV4500 and should drop my rpm's right in to a nice sweet 1900 RPMs cruzeing down the interstate. (i have a RV cam with go low end) I do not regret doing the swap to the SM465 and if I lived where the speed limit was 65 I doubt I would change. At 70 he my doors get blown off by soccer moms. If you are happy with your RPM with the turbo you have now you will be fine with the sm465. I would recommend spending a few extra bucks on a new clutch kit, I dropped a summit special that was under $100 and it has been awesome, but I would have hated to pull the trans because i didn't drop in a new clutch. |
09-29-2017, 08:06 PM | #12 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
I went from 3sp on the tree to 4sp sm465 conversion, due to my old 3spd was shot. Get the c20 drive shaft, you will need this for the conversion. You will also have to get the center mounting bracket that is riveted to the frame, once cut off a donor truck you can bolt it up to your frame. Both of the shafts will be modified, rear lengthened and front complete new. I have 550.00 into the driveshaft with new everything, and balance. Tell the driveshaft shop what rear you have now, the rear ujoint is a adaptor one that connects to the rear. Your going to need the speed corrector piece for the speedometer that bolts to the transmission.
Getting the trans in place and bolted in is a some a beach. Your bell housing is the crossmember, there are no bolt holes in the rear of the 465 for a standard cross member. Install a new clutch assembly and throw out bearing, install disc facing the correct way, install a pilot bushing in the rear of your crank. Allow yourself 4-5 days in the garage, a couple hours at a time. You will curse at some point. |
09-29-2017, 11:42 PM | #13 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
Good info. Thanks. I'll be checking out my frame in the morning. I have a decent idea of where the frame mounts should be for the linkage and cross member. Hoping I lucked out and holes are already there. If not, I'll make it work. Seller has been real helpful with sending me pics from when he tore the donar down to help out.
Definitely going to grab the c20 shaf. He wants some more money for it, but that's expected. Talked with a shop that I was referred to with good reviews and talked out where to go with it. I'll need to save up a little more cash than I was expecting but feel good about it all. They ballparked it from 3-425 but a better number once they get the shafts. I'm definitely going to get a new clutch kit. From what everyone says, the trans is near bullet proof, so might as well put a new clutch in and not worry about it. She will see the highway a bit, but not a lot. I keep her around 2700 which is around 70-74 mph according to my GPS speed. Speed is shot and bounces between 90 and maxed out when cruising the highway. Anyways, I'm ok with the little bit of miles at that speed. Pretty excited to finally get the feel of a stick in the truck. It's been the main thing missing whenever I take her for a spin.
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71 Long bed C10 w/68 front clip, 350 SBC+HEI, TH350 06 Yukon XL Denali - Stock |
09-29-2017, 11:45 PM | #14 |
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Re: Ditching th350 for sm465 questions, maybe GV OD
Also, getting the trans in should be fun. Might try to get a friend or two to lend a hand. I don't want to pull the motor but don't have a trans jack. I have a scissor jack and hydraulic jack that helped a lot when I was working the th350 in place when I swapped motors and that was all done by myself. And yes, I'm expecting to cuss a lot and take breaks to cool off. It's a part of the experience.
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71 Long bed C10 w/68 front clip, 350 SBC+HEI, TH350 06 Yukon XL Denali - Stock |
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