[Mrwalrus295]

I already hear everyone screaming bloody murder over tossing originality out the window, but I intend to keep all the original stuff protected and stored.

It's a 200 i6 coupe with a 3 speed auto and an open diff. All original currently with <60k original miles. I'm the second owner.
End goal? 351w, 5 speed stick, and a posi rear. I don't want to do anything that requires body modifications (cutting, welding, etc).

For the sake of cost, I'm planning to do it all a little at a time. The auto is being a piece of sh*t anyways, so unless my buddy who does transmissions finds it's a super easy, cheap fix, I'll probably just retire the cruise-o-matic and slap in a 5 speed manual. I was gonna go with the T-5 but it appears to only have a max torque rating of 300 lb-ft. If I go the 351 route and mod the engine further in the future, I'm gonna break that 300 lb-ft fast. So I guess if I want to stick with Tremec I should go with the TKO 500 or 600?

Main question: Idk enough about mechanic stuff to know what would happen, but if I end up just TKO swapping it for now and leaving the 200 six, that seems like super overkill for an engine that small. Would it be a pain to drive with a tranny like that coupled with my current engine?

Second question: Since I'll have to switch to 5 lug wheels at some point anyway (and LSDs are just nice to have) I guess I'll go from my stock open diff to a Ford 9" rear and maybe get a 3rd member from Currie or something? (unless I just find a whole axle, diff combo) Any recommendations for parts for this would be a big help also.

 

[coupster]

Doing the conversion piecemeal, part by part will cost more time and money. You would be better off to accrue all parts and then swap with a PLAN. Swrapping in a 5 speed with 6 cylinder drivetrain will cause you to duplicate your work and cost more. To get the 5 speed to work with 6 cylinder rear and driveshaft you would need to modify the 6 cylinder driveshaft (if you can get a yoke that works) which you won’t use with V8 swap, money spent unnecessarily. Just swapping in a V8 engine, trans, and rear is not enough for a 66. You should also convert to 5 lug V8 suspension and steering. I would convert to v8 front/rear first before engine and drivetrain. youll need better brakes to stop the V8. I’ve been down your path with several 68s that I convertEd, and they are easier than a 66.

here is my approach, I don’t know the condition of your car, but most 50 year old cars need EVERYTHING. I assume you want to drive while restoring, so with that in mind….

get car running properly first. Make engine fire, idle, etc. ensure good brakes, tires, then test drive to asses next issues. Disc brakes, steering and front suspension should be done at the same time. You will need V8 parts. Then convert rear to V8, redo brakes on rear, and install new leafs. After all steering and suspension is good, move to engine/trans swap, driveshaft and z bar stuff needs to be sourced. Upgrade radiator, exhaust,. this is a quick list….

 

[Crash8212]

For your main question; SWAP IT! The Tremec would be an improvement no matter what. Yes its is "overkill" for the I6 but it is a direct bolt in for your 351 or basically any other small block you would put in. It puts you one step closer without taking any steps back. One thing to consider though is i believe the TKO requires tunnel mods in the 65 and 66. Check into it.

Im in the same exact boat as you actually except my T-code is a 68 that I got over the weekend. I am already hunting for a Tremec but have to choose which one (and a Coyote). To the guys that say "keep it original", thats easy for them when they started with a GT or at least an original V8 car. No one really wants that sixxer in there! Mine is immaculate and runs like a top but a very weak slow top. Its your car, its your money. Play with each how you want to.

Oh, and as far as the other parts go that will require upgrading, remember the golden rule. Make it stop first, make it turn second, make it go last. Start with brakes and driveline before you swap the engine. Swap your rear end before you do the trans though, no sense in cutting two driveshafts. Do as little work over as possible.

 

[22GT]

Well, the piecemeal idea is probably not workable. Attaching the TKO to an I6 would be a major project by itself.

If you want to aquire parts for the V8 conversion, do that picemeal. Don't forget the front brakes, too. And if the car is a 65-66, the steering linkage. Not to mention the electrical system, fuel system, cooling system, exhaust system…

 

[sheza65]

I already hear everyone screaming bloody murder over tossing originality out the window

Huh, what? I don't hear anything.

The 351W I put in my '65 T code was pushing 500 hp with a T-5z with a few upgrades. It was fine and it took a beating. Lack of traction was an issue, but I wasn't speed/power shifting, dropping the clutch, etc. either.

 

[Tombo]

I'm thinking of/planning a V8 swap into a 1966 as well, wondering if anyone might know if the 1985 AOD transmission would fit inside of the 1966 trans tunnel?

 

[awhtx]

I'm thinking of/planning a V8 swap into a 1966 as well, wondering if anyone might know if the 1985 AOD transmission would fit inside of the 1966 trans tunnel?

Yes, the AOD, 4R70W and T5 will all fit without mods to the tunnel. It's the TKO that requires mods.

 

[cj428mach]

I'd do the rear end and front suspension first. Then the engine and transmission together if you can't swing the whole thing at once.

 

[Tombo]

Yes, the AOD, 4R70W and T5 will all fit without mods to the tunnel. It's the TKO that requires mods.

Thank you for the post ! ! ! One more "problem" solved . . .

I understand that there is an issue with some of the front end parts and pieces that will need replacing to fit a V8 (5.0/305) in the where the six cy,inder currently resides. Something for another post.