I have a 66 coupe that i am looking at replacing the 6 cylinder with a 289 I know i will have to replace the coil springs and radiator. Will I also have to replace the rear end?

 

yes, and the suspension and the transmission and pretty much the entire drivetrain. che ck the FAQs, there is a few links in there that will show you exactly what you need to convert your car correctly.

 

I edited your heading to say I6 instead of V6. There were no V6 Mustangs back then. This has been done a lot, and can be done with a lot of time and effort and money. Basically, the front suspension has to be upgraded to a V8 suspension with 5 bolt hubs, and if you have a 3 speed manual, that tranny will have to be replaced because it is a weak 3 speed that came with the sixers. The rear end has to be upgraded to at least an 8" rear with 5 bolt hubs. The 7 1/2 inch rear in the six is just too weak for a V8. The engine wiring harness will have to be replaced. This is just the tip of the iceberg. Usually, it is cheaper to start with a V8 car and upgrade from there than it is to replace all the sixer stuff to make it a V8 car.

 

Thanks

 

and if you have a 3 speed from your I6 (200ci, i'm guessing?), i know someone who will gladly take it off your hands *wink, wink* *nudge, nudge*

 

thanks for thinking about me first clu7ch, but im looking for a 5 speed

 

Clu7ch was talking to Jeremy. Go back to sleep.

 

dont have to tell me twice. how did you know i was napping??

 

cause you totally missed the humor in my post. wait, there was no humor. i really am looking for a three speed for my I6. [&o]

 

Too bad I didn't know that earlier. There's one in the Weld County land fill if you want... And it was from behind a V8.

Personally, go for the 4-speed WR. You'll really appreciate that extra gear ratio right before straight through...