i have a 65_289 with a 8" rear. i plan to get my engine up to 350HP+. i want posi but i dont know if the 8" can stang that much power? if it can what do i need to do? or should i get a 9" posi. ?

 

get a 9" the 8" won't last long

 

Ditto.

 

Disagree 8" are excellent rear ends. They will handle all kinds of power. If you are building the rear end with gears and a posi, put new bearings and seal on it. It will be plenty strong as long as you are not dumping the clutch everytime you start out.

 

Also if you have an 8" now you are half way there. It will be much cheaper to build your 8 than to convert to a 9.

 

Not true, you can build an 8 inch and have it handle 350 hp with no problems.. I just did mine, did a complete rebuild with 3:55's and a richmond locker. It should handle up to 400hp with NO problems at all.

 

They 8" is plenty. You know it all ready fits your car and with all the disc brake conversions now days for these rear ends you can do pretty much what ever you want with it.

 

depends.... I found a 9" that just needed sand blasting and some brake work for $250 it won't cost you that much more to just go 9" and you'll feel more confident in it.

My theory is why do all the work for something that should be good enough when its not that much more expensive to go with something you KNOW will work.

 

I have broken two 8's with nothing more than a warmed over 302. It's not the gears, it's not the carrier, it's the case. They crack at the pinion pilot bearing boss. That's why Ford put nine inch rears behind HiPo 289's.

 

well i guess i'll wait until i find a good priced 9" because i dont want to risk it...