I have started working on this project i am wondering if anyone has any advice on upgrades I'm starting with a fairly good body i want to use the th350 with a shift kit and ratchet shifter maybe a trans cooler? a hydraulic e-brake change to poly body bushings i have been looking at hotchkiss springs bilstein shocks any advice or help would be appreciated.
http://i778.photobucket.com/albums/yy63/crajg1971/IMG_0155-1.jpg (http://s778.photobucket.com/albums/yy63/crajg1971/?action=view&current=IMG_0155-1.jpg)

are you familiar with the bubba drift el camino? they competed and did fairly well in an 86 el camino with a th350.
http://www.bubbadrift.com/index.htm
and since you are interesting in drifting, im going to assume you are on a tight budget as everyone who wants to drift is....including me haha.

one of the first things i would do is put in a steering box with at least a 12:1 ratio, get some affordable 17inch wheels(soft 8s look good on an el camino/sprint) to open up your tire options. for the ebrake, im not sure what route you were thinking, but the popular/affordable inline "staging" type hydraulic ebrake might not work so well with drum brakes so you might want to look into upgrading your brakes, or going to a dual rear caliper setup. our cars are notorious for understeer, and in a sport where you are inducing oversteer this is a fairly large obstacle. I'd look into sc and c stage II kit. also, your are going be sliding everywhere in your stock seats, so add in seats and harness. some quality upper and lower control arms out back, and of course shocks and springs. circle track springs are very affordable and as long as you keep your spring rates under 550, the hotchkiss bilstein shocks are very good for the money. to pass tech inspection your steering gear is all going to have to be in good shape. i could keep going... unfortunately, getting older cars to be happy going sideways isn't cheap...but i completely understand you wanting to do it and i hope you do:) good luck. keep us updated.

mp4659 hit it well. Probably need a good rear sway bar so you can get it to oversteer. I've been looking into hydraulic e-brake setups myself and will be fabricating something soon. Looks like a lot of them are just a remote reservoir master cylinder inline. Read through some of the threads in here and you'll find most of the suspension info you need.