link to Dave's thread on his mini-jig

the original jig was built by James (bigblockranger)in texas, his spanned the entire head, and bolted to it using the accessory holes on the front and back. he did the same thing as Dave, built it off of an old LA head (accessory holes are in the same spot between mag and LA heads)...Dave's is a pretty neat and simple design, too.

since you're on a budget, I'd use Dave's suggestion, redrill, and tighten to 25-30 ft-lb...one caveat with the edelbrock magnum intake is the water neck is in the magnum position (biased towards the pass side)...you may run into interference with it if you're running A/C in an older vehicle, most likely a '80-91 vehicle.

as far as cam, the biggest cam I'd run with stock spring is MP part number P4452757, which is 248/256 adv, .410/.425 lift with 1.5's (which is essentially a stock 360 cam). with the 1.6 mag rockers it'll actually be more like .437/.453. even at that, the stock mag springs will start to float at about 5000-5200 RPM. the 340 cam is 267/276 adv duration, .429/.444 lift with 1.5's, or .458/474 with mag rockers. it'll float the valves sooner, and you may have coil bind issues with the stock springs.

Here's my post in the archives about the GM3100 springs

I'd defintitely spend the $140 and get some GM 3100 springs and retainers from gmpartsdirect.com. or if you're cheap, start pulling them off of cars at the junkyard with a valve spring compressor for heads on the car. with these springs, If you're set on a MP cam, I'd use the 260/268, .430/450 lift cam. a comp 260 duration high energy cam would be good, as would a comp XE256. if you're cheap, either summit cam kits would work ok, the smaller one would work better on a street and/or heavier car.