I recently purchase a 76 TA with a 455 4 speed.  It is all orginal with only 36K miles.  I want to upgrade the motor without spending a great deal of money, primarily looking for low end torque.  I know the HP on these motors was around 200 so my guess is that it could be brought up through headers, etc.

Any advice or acticles that I can go to?

Many thanks!  

If you're not worried about keeping the car exactly original and want ot increase your driving enjoyment, I'd recommend getting a set of Edelbrock's aluminum 455 heads for the motor. They flow much better than the stock 455 heads, and will take about 50-65 pounds off the front end replacing the cast iron heads with aluminum ones.

After that, the next thing I'd look at is a good high-flow cat converter to replace the factory unit. That along with headers will have your T/A running nicely for nto a huge investment.  

Several years back, Car Craft or one of the street machine mags ran an article on just such an animal. They found that the biggest gain came from the camshaft as Pontiac used either the 066 or 067 cam in these motors and it was way out of breath before the heads or the intake and exhaust manifolds became a restriction. To go the cheapest way, I would look for a set of 6X or 5C heads of a mid 70's 400 to bring the compression up from 7.6:1 to around 9:1 and swap out the small cam for something a little stouter like the 068 or 744 or equivalent aftermarket sticks. Keep the stock intake and exhaust manifolds with a good set of dual exhaust and no one will any the wiser. Oh yeah, spend the rest of the money buying new tires, you'll need'em!
Steve