Hey guys..

I have a 67 c4 auto in my car and will be putting in my new motor this week which by desktop dyno could be pushing close to 450HP (new 347 Stroker short block with forged internals, TFS CNC Ported Twisted Wedge heads, TFS Stage 2 Cam .542/.560 lift 224 duration at .050, etc etc)...

From what I understand, a stock 67 C4 has fewer spline than a 70 and up.(?) Do I NEED to upgrade this? A local performance tranmission shop first told me to upgrade to the 70 and up 28 spline, but then said if I'm not running slicks that I don't need to upgrade that and just a band upgrade, clutch kitupgrade, shift kit and new converter will do the trick.

Anyone have any good input on this? I want to make sure I do this right the first time. I will not be racing the car, I just want to make sure I take this old stock tranny and make it capable of running this new higher HP with no issues, plus get a better ride from the 2500 stall and shift kit.

Thanks in advance

 

With what you have done to the motor so far,, If I were you ,, I would definately put in a 5 Speed.. It only makes sense..

 

nah..keeping the auto...