Where are you racing and what are you up against? All the horsepower in the world doesn't mean a thing if you don't have the skills and tires to use it. Also, if you're hitting the corners, chassis and brake upgrades will give you more speed for your money than motor work.

Carguy, its all good I expect flack. I give my customers at work for hell running v6 mustangs. It came down to this car and an 87 305 automatic. I like my g forces sideways, so I chose the v6 for better weight distribution, a stiffer chassis, and the stick.

In the OPs shoes, I'd go lz9. 3900 v6. 240hp/240 torque. Huge power band. Strong internals. 350lb longblock

 

I know this is an old thread, but no one mentioned the 400 sbc. It would fit right in a third gen, and has potential for loads of torque and hp.

 

and has a tendancy to run very hot as it doesnt havent coolant jackets, but steam ports. the 400 is ok when left alone, but the cylinders are very thin

 

This makes sense. I had a mechanic try to sell me on a built 400 for my IROC. I was not aware of thin cylinder walls, and trouble keeping them cool.