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Discussion Starter #1
Hello All,
I am now ready to start motor work on my 1984 ELKY. According to the research I have done on this site the shape of the tranny pan indicates that I have a TH350. Will that tranny work with a mild big block motor or only with a small block?
I know a 350 sbc will drop right in but besides heavier coil springs, what needs to be swapped to make a big block fit?
I know I can get a new 350 $1499. I see 454 big blocks out of trucks for sale in Los Angeles for $750.00 tested for compression and supposedly from vehicles with less than 60 k miles.
Also, would my quadrajet carb from the stock 305 work with a big block?
Never done this before and need answers.
RTT
 

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You've double checked that tranny? The TH200 and the TH350 have similarly shaped pans. I assume you knew that, but you don't want to get too committed and find out too late.
 
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I'm pretty good when it comes to engine combo's but I have to say DO NOT HOOK a 454 up to a 350 transmission! A 350 transmission is a great transmission but if you're going for power,a 400 would stand up without a doubt even though it may be heavier. As for the swap,be prepared to do some stuffing and modifying to the suspension.:texas::beer:
 

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Discussion Starter #5
Sounds like a small block is the way to go. Will both the TH200 and the TH350 work with a 350sbc motor?
RTT
 

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Th350 will for sure fit. I have heard they a good one to use. Its either the th200, or th250 that has a bad reputation. Not necissarily a bad reputaion just some people with those switch to a different tranny.

Might i ask why no o/d? And a 3 speed is harder on the engine. Thats what i got a TH350 but an o/d wouldnt take as much gas.

Anybody know the advantages of having a non o/d tranny over an o/d tranny?
 

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Discussion Starter #8
I drive my elky mostly just to work and back 5 miles on surface streets. I was hoping to use the existing tranny. I dont see hydramatic stamped in the bottom of the pan? Thanks for all the info guys.
RTT
 

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Oh i guess i didnt read it well, i thought you were buyin one.

Oh TH350 has 13 bolts with a swuare and a corner cut out pan if thats any help
 
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I have a 350c transmission with a stall converter that's been beefed up to handle my engine. It has the optional lockup but I haven't used it yet. Seems like you won't be driving enough to use an overdrive so I say go with a 350 transmission!
 

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Discussion Starter #12
I did a little more investigation. Tranny pan has 13 bolts and is slanted across rear drivers side corner. There are no words like hydramatic or metric stamped into the bottom of the pan. Just kind of an x design in the bottom of the pan. Does that make it a TH 350?
RTT
 

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the factory put a lot of 350 s in thier trucks with big blocks it will live fine if its a good trans and not a race 454. truck 454 s are only 7.8 to 1 not a tranny killer. i ran a 350 behind a 455 buick in a 84 regal. and it lasted the 6 years i had it just fine. a 455 buick has twice the torque as a late model 454. i wouldnt be afraid to run it
 

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metric and an x across the pan sounds like a 200 or 250 not a good trans for a big block. if its a 250 it will have a external band adjustment screw on the pass side of the case about midway down the case. a 350 pan is smooth on the bottom with no stampings at all
 

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a 400 is a great bulit proof trans but such a hp hog it takes 35 more hp. just to operate it. the 350 if built with good parts will live fine behind a big block just fine.gm used them in the mid 70s 3/4 ton trucks with big blocks and were fine. i have put 700r4 s behind some pretty strong 454 s and had them live for years you just have to use all of the good stuff no cheaping out on them.my cost to build a 350 with the best parts compared to the to the high energy part i use normally is another 75$ and a little more for the 700r4 s
 

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Nobody mentioned you have a Computer Controlled Carb. Won't work without a comp.
 
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