i have a 1985 firebird that i have been restoring and i am going to put a 383 in it with about 400 horse maby a little more. is there any major work that i need to do to my chassis so all that power won't tweak my fram. i have T-Tops also. thanks guys.

 

Big difference between the title of the topic, and your actualy problem. That 383 isn't going to do much to your suspension, but it will wreak havok on your unibody.

Weld-in subframe connectors should just about do it.

 

is what i think would be best. If you have ttops you may want to check out these sfcs as well..

click link

https://www.thirdgen.org/techbb2/sho...hreadid=335711

 

With that power, I would redo some of the bushings on the rear end too. Torque arm, panhard bar, lower control arms. I would replace them (I am with the L03) to make the car handle power in turns better. I would at least get some new polyurathane bushings if not replace the rods, bars, and arms themselves.
But that is just my .02.