67 v8 swap - will tranny bolt up?

IIRC starting in 1967 Ford used the same 3-speed behind both I6 and V8 motors.

68RCodeConv is correct, the same 3 speed was used for V8 and I6 engines beginning in 1967. Yours will bolt up just fine with your bell housing and clutch, but since you are at it I'd buy a new clutch kit for a V8, and don't forget to change the pilot bushing and throwout bearing; always good insurance. Come to think of it you may have to buy a V8 equalizer bar though.

I once swapped out a 1966 I6 3 speed trans (diffent than the 3 speed you have) for a V8 Toploaded 4 speed tranny. I used my I6 flywheel and a V8 bellhousing and clutch and it all bolted up to my I6 block with no trouble. Best swap I ever made!

The equalizer bar is what pushes on the clutch fork when you press the clutch in. it is a bar that sits in pivots bolted to your frame rail and the driver-side engine block. It has an angled arm welded to the center and the clutch adjusting screw is held onto the other end with a cotter pin. Late model cars use hydrolic clutches so there is no bar on them. On old Mustangs there were different bars for regular V8 engines and Hi-Po V8 engines because the hi-po engine's exhaust manifold was in the way of the regular bar. I don't know if the V8 bar was different than a I6 bar though. Best to check the Mustang Parts catalogs and see if there is an I6 one. If there is you will need to buy a regular V8 one as long as you are using stock standard headers. If you plan to use Hi-Po headers you'll need a Hi-Po equalizer bar. If you plan to use Tri-Y's you'll have some clearnace issues as well; the Hi-Po equalizer bar usually works but sometimes you need to modify the bar and or header. That's the pain with equalizer bars, they get in the way of headers. I decided to just stick with standard manifolds since I'm not building a Hi-Po car and plan to use mine for shows and cruises. Good luck with your project.

I had the same set up (I6 3spd manual). When I put in the 351w, I kept the same clutch linkage and transmission. Mated up just fine with the bigger bellhousing.

But my $.02 is to trade out the tranny while you have it all apart. The 3speed never gave me a problem but with all the extra HP, it was a PITA because of the gearing. You'll have a lot of HP you'll never have access to. I just put in a T5 and it's like driving a different car.