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Discussion Starter · #1 ·
hey guys, :seeya:
I have 2 65's, both sport coupes, one with tri power. Currently restoring one, and I am looking to find a transmission to replace the 2 speed auto, I am open to options, so long as it is a 4 speed or better, preferrably something newer. The car is going to be a street driver, and hit the 1/4 every once in a while. So far I have found that I would most likely be going with a TH350 or 400. Are they both compatable with my 389 or will I have to do some extra work (shorten the driveshaft, move mounts etc)? I have also heard that the 400 is a little more beefy and requires more power. Planning on tri power, ram air, new cam, roller rockers, pipe and exhaust manifold, would that be enough to push the 400?

Any input is greatly appreciated, im just a 16 y/o kid lookin to get my dream car runnin again =) Next door neighbor is talkin about a 700-R4 tranny, sounds like it would be a little more work to get it to work though?
 

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it all depends on what you are realy looking for from the car......if u you want to run high gears, how streetable you want the ride to be and how much modify you want to do to the car.......And how much money your looking to spend......the 350 and 400 are very good choices for drag raceing and streetabality (depending on rear end choices) both are proven platforms, that require little or no mods to the car it's self. The 700r would not be a direct bolt on and may reqire modifing the trans tunnel of the car......(you would have to find an adappter for this choice due to the chevy patern).......anthor choice is to go with the 200r it has a universal GM patern.....(this trany requires a total rebuild to strenthen it for raceing).....just some thoughts.......what ever your choice would be your still looking to most likey replacing drive line, trans mounts ect.

ps this is a general answer to your question I don't know how much differnt your car is to a 68 but this is the problem I run into with mine thanx
 

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Discussion Starter · #3 ·
awsome, thanks for the info! I'll have to look into that 22r, most likely scrap the 700 idea, right now I am thinking 350 or 400 unless anyone else has some suggestions. I can fabricate minor things, I just dont wanna have to rip everything out, my main concern is the bolt patterns and clearance. I need to replace the gears in the back soon anyway, so that isnt a major issue.
 

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Discussion Starter · #5 ·
sweet,that looks like my missing link(age). Decided for sure now on the TH400, i know thats gunna mean moving back my crossmember and shortening the driveshaft, plus this handy shifter conversion 05 just showed me(thanks).

I know this has been done a few times, so im sure someone on here can tell me if they have run into any problems switching over to the 400, or any other info i need to know, thanks a bunch
 

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just rember to try to find the short shaft 400......if not U might run into problems with the E-brake cable.....also I think the short shaft 400 is the same lenght as the 2 speed and 350 meening all U would have to do is replace the yoke......it's been awile but I think there the same lenght.....
 

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Discussion Starter · #7 · (Edited)
That sounds very nice, about being fitting and all. i have 2 more questions, both thanks to my neighbor.

~Can i push the 400? the engine is being rebuilt, trying to punch 400 ponies, i think it would be fine but he has some doubts

~When you say the trans tunnel doesnt fit do you mean the casing of the 700 dont physically fit, or just the bolt pattern requires an adapter? if the cases fit i reckon i can go for the 4 speed 700 for the extra work, and got a free rebuild of a 700 courtesy of paradise chev. (if i do buy a used one)

Thanks a bunch!

Edited due to bad wording...thanks especially I2BE, youve been a HUGE help..beautiful car btw
 

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The problem so I been told with the 700r is it's gerth, (bigger in the middle) than say a 400 or 350, and yes U would have to find an addapter, it will bump the trany back 2 or more inches. look at the trany U now have in the car, and if U can't put hand between the tranny and the firewall then ither U need the moter foward (something I would't do) or U need to move the trany back. Where's the front of the 700r going to go......right in the firewall. Not to say stay away. I love the 700r, and if U want to go that way great, again I don't know how much work U want to do to the car.

And to answer your question about the strenth of the 400, I run a 400 in my car before I had kids it was my bracket racer 400 standard bore decked 6x heads about 9.5 and 200hp nitros shot makeing 475hp and 460fpt. running at the track on 10in slicks, broke the stock driveline. Had kids, reheaded and recamed the car, still running the same tranny and that was 7 years ago still shifts HARD........Yes some might say the 400 is a good trany. :lol:
 

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Discussion Starter · #9 ·
hahaha awsome, that settles it for sure. the edelbrock performer rpm kit alone should get 420 hp, so i think i'll have the power!

I FEEEEL THE POWAH! front end of GTO is completely off, gettin ready to pull out the engine and tranny, and get some real work done :cheers
 
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