Okay, I've read through some of the posts on shift kits, but nothing really answered my question.

I just bought a 70 mustang from a guy. He had the engine rebuilt, and I'm still in the "break-in" stage. He also had a shift kit installed on the C4 transmission. I didn't really think much of it, so I didn't ask him what kind it was, etc.

When I go from P to R, it really shifts hard, and has killed my engine a couple times... I mean, the whole car shook forward a few feet. I had to fly through to D if I didn't want it to kill. Is this normal for a new shift kit?

 

i had a B&M stage II kit in my first C4, it hit gears hard but nothing like that. I have a TCI streetfighter valvebody in my current C4, and its very close to the B&M.

what are your RPMs when shifting from park to reverse? too high maybe?

 

my park to reverse also shifts really hard. I have a shift kit in my C4 too but I think the reason that it is shifting hard is bc my rpms are a little high bc I need to rebuild my carb. But once the RPMs are lower I think it will still shift hard but probably not with the shudder and everything

 

mine shifted the same way. i did lower my idle soeed and it went away for the most oart. do be sure to have enough aft in that thing!

 

Your idle is definitely too high....only option