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03-04-2021, 06:02 PM | #1 |
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71 C10 auto crossmembers
Doing a frame off on a 71 shortbed. The original truck is a 250 with a 3 on the tree. Because of the condition of the frame I bought another 71 frame and it had what I believe to be an auto trans crossmember. The new truck will have a 292 and auto in it. So my question is are there different auto crossmembers? And how would I tell which is which? Thanks guys
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03-05-2021, 08:01 AM | #2 |
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Re: 71 C10 auto crossmembers
Far as I know, you can use the same cross-member for various transmissions. Just slide it (back normally), drill mounting holes if they don all exist and you are good. I would get the proper tranny mount, bolt it to the cross-member and adjust, then drill
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Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
03-06-2021, 09:45 PM | #3 |
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Re: 71 C10 auto crossmembers
Six or V-8, 3-speed or automatic, cross members are the same and in the same location. And drive shafts are the same length.
At least that's the case with a TH350 and 3-speed Saginaw, as well as Muncie 4-speed.
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Mike 1969 C10 LWB -- owned for 34 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 23 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; 03-06-2021 at 09:55 PM. |
03-06-2021, 09:50 PM | #4 |
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Re: 71 C10 auto crossmembers
I swapped the factory Th400 for a th350 using the same crossmember just moved forward and bolted in a different set of factory holes.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
03-06-2021, 10:18 PM | #5 |
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Re: 71 C10 auto crossmembers
Isn't the 3 speed manual trans cross member riveted to the frame and the bell housing bolts to it.
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03-06-2021, 11:01 PM | #6 | |
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Re: 71 C10 auto crossmembers
Quote:
I thought it was only pre-1958 vehicles that used front engine mounts, and bellhousing mounts. At least that was the case with Chevy cars. Like this:
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Mike 1969 C10 LWB -- owned for 34 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 23 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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03-07-2021, 02:30 AM | #7 |
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Re: 71 C10 auto crossmembers
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03-07-2021, 10:19 AM | #8 | |
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Re: 71 C10 auto crossmembers
Quote:
Did it use front or side motor mounts? Was the trans supported, or just hanging out there like pre-1958 cars?
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Mike 1969 C10 LWB -- owned for 34 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 23 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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03-07-2021, 10:43 AM | #9 |
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Re: 71 C10 auto crossmembers
For the 67-72 trucks there are auto cross members 6 manual and V8 manual trans cross members and 4 wd are their own animals , Depending on each application determines where they are mounted in the frame. The stock cast iron manual bell housings are rubber mounted to the cross member with the cast iron trans 3/4 speed hanging off the back with NO tail shaft mounts . The frames are all drilled for the different stock cross members . There are multiple drive shaft lengths be it 1 piece , 2 piece , long bed /short bed . There are no front engine mounts used on the 67-72 trucks
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1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop |
03-07-2021, 12:08 PM | #10 |
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Re: 71 C10 auto crossmembers
The old frame has a bell housing mounted crossmember for the 3 on the tree. The new frame has one mounted much farther back, I’m assuming it’s an automatic crossmember. So depending on the location it should fit whatever automatic I choose?
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03-07-2021, 12:22 PM | #11 |
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Re: 71 C10 auto crossmembers
This is a pic of the V8 and 6 manual trans cross members , V8 on the bottom .
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1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop |
03-07-2021, 01:29 PM | #12 |
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Re: 71 C10 auto crossmembers
Grumpy old man I’m trying to post a photo of what I have but being unsuccessful. It looks as though it’s the V8. Will this work with the 292? It’s that a manual crossmember?
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03-07-2021, 01:41 PM | #13 | |
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Re: 71 C10 auto crossmembers
Quote:
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03-07-2021, 01:41 PM | #14 |
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Re: 71 C10 auto crossmembers
I had a 6 cylinder I used with a V*, just had to drill 2 holes in frame for mounting that didn't line up, so I would assume it works the other way also.
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Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
03-07-2021, 02:07 PM | #15 |
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Re: 71 C10 auto crossmembers
Thank you old51sedan I have the 292 mounts and perches. How does it do with the 200? What gears are you running?
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03-08-2021, 10:13 AM | #16 |
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Re: 71 C10 auto crossmembers
That's a good question. It has a 3.73 rear end which should be fine. I'm currently in Florida for the winter. I have it all together, running, but haven't had in on the road because of no exhaust. Since I've been hear I have bought a 4 barrel intake and a 550 Holley for it. Also have a new set of cast iron headers, so I will be installing all of that when I get back, then the exhaust. Hopefully it will run out fairly well. Good luck with your project.
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03-08-2021, 10:23 AM | #17 |
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Re: 71 C10 auto crossmembers
Thank you. You as well.
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