Author Topic: th350 to 700r4 swap  (Read 11903 times)

Offline chrpmaster

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th350 to 700r4 swap
« on: September 29, 2008, 08:46:47 am »
How big of deal is it to swap out a th350 and put in a 700r4?  I have a 76 c10 LWB 2WD with 350.  I would like the overdrive for highway driving and have located one cheap locally.  Do I need different cross member and drive shaft?  I know I need to do some wiring to make it shift properly but will get some help from a local tranny shop.  What should I look at before I buy the 700r4?  The guy is selling it for $50 so I figure it needs rebuilt and said he didn't remember what it was out of so I don't know the year, engine etc.  Are there serial numbers on it somewhere I could match up that would tell me more info before I buy a boat anchor?

Thanks
Andy

Offline VileZambonie

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Re: th350 to 700r4 swap
« Reply #1 on: September 29, 2008, 10:12:03 am »
I've posted a few times where to look for the date codes. Try searching. Also you can look for the casting line around the cooler fittings. If you remove the pan you can see if it has the auxiliary valve body.

For the swap you'll need to move the crossmember, the torque converter, TV cable and brackets, and depending on tailshaft length driveshaft modification.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline dumbucket1

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Re: th350 to 700r4 swap
« Reply #2 on: September 29, 2008, 01:02:51 pm »
search function isnt working right now
Chevy and GMC trucks ranging from 1973 to 2007

Offline 80stepsideguy

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Re: th350 to 700r4 swap
« Reply #3 on: September 29, 2008, 01:27:21 pm »
I heard from like 87 n up the 700r4s were good from 86 down the pump is notorious for letting go. I had a 83 k5 blazer that the pump let go on me and ended up putting in a th350. But i couldnt afford at the time 1,000 for a 700r4 (back in 1993) but i say for that price snag it and have a tranny shop look at it and figure out what it came out of and have it rebuilt.

thanks
pat

p.s. I found a 700r4 myself in the local craigslist that came out of a 88 formula firebird that was bolted up to a 383 for 175.00 s ofor 50.00 thats a steal itself.
1980 Chevy c10 restomod:  350/700r4 12 bolt 3.73 rearend iris blue metallic
1998 Chevy 1500 S/B 2wd
1970 cougar convertible: triple white 1 of 1
1931 Ford Model A roadster(family inherited)
2014 Hyundai Tucson Limited(my daily driver)
2023 Kia Sportage X Pro (her daily driver).

Offline chrpmaster

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Re: th350 to 700r4 swap
« Reply #4 on: September 29, 2008, 06:57:06 pm »
I got more info from the seller though I'm not sure what it all means.  He said there was MD8 in large letters and he thought the serial number is TD4508101.  He didn't know what it came out of but he thought it might be a van due to the large mount on the tail shaft.  Any info you can give me would be appreciated.

Thanks
Andy

Offline Captkaos

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Re: th350 to 700r4 swap
« Reply #5 on: September 29, 2008, 07:32:04 pm »
The number is on the rear passenger side of the transmission above the pan.  It should start with a number not a letter.

Found Viles Post..
http://forum.73-87chevytrucks.com/smforum/index.php?topic=3840.msg17681#msg17681

Offline VileZambonie

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Re: th350 to 700r4 swap
« Reply #6 on: September 29, 2008, 07:55:59 pm »
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10