fender headers

Homeboy,

I have had a number big block A bodies, all 440s and have never had any problems with structure issues.

That being said....

You will tweak the frame even if you dont use fenderwell and don't reinforce the unibody. Common sense says that if you pick the front wheels up off the ground and with the body naturally twisting something will give. Nothing else but a tweaked frame will occur without stiffening up the frame.

Headers on a B motor, as opposed to RB, will hang lower due to the fact that the heads sit lower on the b block.