It's been awhile since I've chatted here as I've taken many of your advices and have been getting my motor rebuild going. I have a 68 convertable with a 6cyl that's been in storage since I bought it, and I'm converting to a 289 from a 66. I haven't started taking apart the 68 so I don't know what's in it...except the 6cyl. I purchased the whole drive train from my friend with the 66, but I'm wondering if I'll need the tranny and rear end. My question is what are the chances of my tranny in the 6cyl 68 being a C4? Were there many different trannys and rear ends? Were the 6cyl and 289 rear ends both 9"? Should just change everything from my 68 to the 66. The 66 tranny is a C4. I have no idea if the 66 had problems with the tranny, but I doubt it as I think its fate stemmed from the spun crank bearing, however it's been sitting for 25yrs or so. If I should use the 66 tranny what should I do to resurect it properly?
Thanx.

 

If the transmission in the 68 is currently an automatic, then it should be a C4.
The rear ends from the 66 to the 68 are not interchangeable. The 66 is narrower than the 68's. Neither is a 9".

If it's been sitting for 25 years, I'd take it to a shop and let them overhaul it. New bands, new actuators, new seals...etc. It'll be worth it.

 

Should I just go with what's in there or try to find a usable rear end? I just dont' want to put the 289 in and blow-up the rear end. Is there a difference between the rear end in the 6cyl and the 289? What's in there now is working and what I bought has been sitting...so if the rear end will hold up to the extra power then I'll leave it, but if it can't handle it I'll have to swap it out
thanx for your help...

 

The 6cyl. rear end cannot handle the V8. It'll likely break on you. It's thje smaller rearend. To do it right, you need to get a 67/68 V8 Rear end.

 

Be advised that the 66 C4 has a different shifting pattern than a 68. It can be changed.
Jim

 

all 6 banger mustangs use a 7.5 rear end and its a 4 lug the smallblock ones where a 8 inch the big block where a 9 inch. yes you need the tranny too or yours rebuilt with different gears in it the c4 was used on the inline 6 and v8 but was gear differently