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Discussion Starter #1
I have a 1967 coupe with a modified 289. The modifications are all simple and basic (think Edelbrock's top end performer kit). Also headers, dual exhuast and 4 disc brakes.

Currently the stock 3 speed automatic transmission is in use. One more step I want to make is to change the rear to 3.55 or 3.70s gears. This car is a street car only - but I do like to have a little fun from time to time. I do however plan on taking some highway trips with it.

This means that the new gears would run my rpms too high on the highway and I don't want that. So I'm thinking of swapping for a transmission that can handle the full range of what I want to do. I would prefer a manual but I don't know how much extra effort that will be or if it would be worth.

Any suggestions (on both automatic and manual) would be appreciated from what type to use, what's worked for you (or that you've heard of), websites I can order from and who I can trust.
Thank you in advance.
 

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here is a nice read on this from mustang monthly that might help ya,
i was going to do this (aod swap) before i had a c4 rebuild
a 1970 and later c4 can be made into a very solid tranny if you want to go that way , it has a bigger spline -26 and with some mods ( h servo added and the #9 thrush washer modded for better lubrication) can handle around 450 hp , cant go wrong either way :bigthumbsup
 

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Discussion Starter #4
Alpha Male - Can't thank you enough for showing me the link to that article. Just the first few paragraphs helped me make up my mind to do the swap. Now just have to decide between automatic and manual.
Anybody have any suggestions or advice in that deparment?
 

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Discussion Starter #5
Should have said thank you to Andrew as well. I'm reviewing all the links right now - didn't want anybody to think I didn't appreciate both responses. Thanks guys
 

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The AOD would be a great swap or a T5 just depends on if you want to change pedals, workout the clutch linkage etc.. if you are happy with an Automatic, get an AOD.
 

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it comes down to preference. do you prefer your performance vehicles to be automatics or manuals?? that will give you your answer. For me, i'd never EVER own any performance vehicle that had an automatic (unless I was building a bracket racing 1/4 mile track only car)

a t5 was the only choice for me, and it's a simple swap.

the aod is a great choice for automatics. Just keep in mind though, that a stock fox mustang equipped with a t5 will be a full second faster in the 1/4 mile than a a stock aod equipped fox. auto's and aods especially eat up so much power, it's not funny. To get that power back, you better put a shift kit in, a good torque converter, and a manual valve body doesn't hurt either. Also, depending on how much power you're pushing the aod's have a hollow input shaft which should be swapped for a solid one.
 

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Both a aod and t5 are kinda weak stock but build it up some both will take a beating.It just comes down to you want a auto or stick and how much you want to spend.
 

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Discussion Starter #9
Gonna go T5 with it. Just can't see completing a car I've always wanted and not making that final swap (always wanted manual). What do you mean by build up as far as the transmission goes? The only thing I know about a transmission is where it is and... okay, I know where it is.
 

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what is your aprox hp level?
 

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Talk to modern driveline he can build you a kit that will have a tranny to hold up to whatever power you tell him.Only thing you will have to do is maybe shorten your drive shaft or switch yokes.
 

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Discussion Starter #12
I can't answer the hp question right now. I still have to replace the heads and even that has to wait. Problem is I'm overseas and won't be home for a few months - will have been gone a little over a year. All this is just research so just before I get home, I can start making the arrangements to complete the work.
Who is modern driveline?
 

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t5's are so under rated, it's not funny.

the vast majority of people on this forum are still running the vintage 289 in their cars. that's 150 hp from the factory. Add a good 4 bbl setup and exhaust and MAYBE on a good day, that's 200 hp. That's still less HP than the 80's/90's fox mustangs had with a stock t5.

the fox mustang crowd are typically running heads/cam/intake combo's with their stock t5's, and HP in the 300+ level.

I'd say an extremely small percentage on this board has upwards of 300 hp+

a stock t5 will handle 300-350 hp all day long. that's double the HP of a vintage motor. A z spec t5 will handle up to 450 hp if you don't race it.

powershifting the t5 is the issue. never do that, and it'll last you a long time. IMO, do NOT waste your time on a built t5 (beyond a z spec t5) if you're not running a minimum of 375-400 horse. My unofficial rule is, 300ish hp and less, you're fine with an 85-93 stock t5. 300ish and up, i'd suggest a t5z, unless you never see track time.
 

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not sure what those are?
 

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modern driveline is the 2nd link i gave you.You could even go t56 if you got the money.A sequential tranny is more of a import thing and i doubt anything american would ever use one.
 
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