converter change

I was wanting to find out if a \6 converter fit in a v8 904, The \6 is a 63 and the v8 is a 66 904 or do they have different spline's.It act like it will work but won't slide all the way back. I have a newer model 904 out of a \6 and it will go right in but the end that goes in the crank is to big.Thank's for any help.......

The crank snout got larger ~1968, both in the slant and small block engines. You can get an adapter ring to go from early converter to later engine, but not vice-versa.

You must keep rotating and wiggling the converter until it goes all the way in. I think the 2 tabs on the front pump drive are what must align to allow this. When all in, the snout should be at least 1/2" back from the front of the case. The manual shows holding a straight edge across to verify. If you don't do so, it won't bolt up correctly to the engine, and you risk destroying the pump if you force it. Tranny rebuilders install a strap to keep the converter seated, and also to support its weight when shipping. Don't remove until the tranny is almost installed.

I don't know if slant and V-8 converters interchange.

Slant and small block converters should interchange in that range. There was a change in input spline count as well but I forget when that happened. Flex plates have different bolt patterns though on the crank flange.

In 727s the spline count changed in 67.
IDK about 904s.I can't recall a spline change until the loc-ups came out.
The 904 input shaft doesn't care about /6 or V8. However a/6 TC will have a higher stall behind a teener

I think Bill's on the right track. Sometimes they are tricky.

Sometimes it's easier if the tranny is out, to have it standing on the tailshaft so the convertor can drop straight on it.

you still gotta wiggle it. Actually, you rotate it: push it on and....in,clink.... turn-----klunk! Seated..You can bolt on a 1/2 box end wrench to the inspection boss to hold the convertor in.

That converter should fit that trans, its a matter of pulling it out slightly and pushing it back in and doing this while turning the converter about 1/2 inch at a time until the converter goes back all the way, kinda like of what pishta is saying. It's just a matter of lining up the pump and the drive spline.