carbed turbo?

I dont know a whole lot about the carbed turbos but buy the car, pull the engine and anything else valuable then scrap the rest. Between selling the good parts and the money from the scrapper you'll get your $150 back.

The first thing to remember is that the carb turbo resondes to the same mods that make the EFI turbo gain more power.

You can buy a wastegate bypass kit to build more boost
http://www.boostvalve.com/infofaq.html

Then you need better spark. Something like a MSD-6 and a very high energy coil would be good. Large low impedance plug wires are a must to deliver max voltage.

A turbo profile cam in a ported and polished head will gain a large power increase. I would also get a multi keyway cam sprocket. I dont recommend a adjustable cam sprocket for street use as they have a tendancy to slip.

You need to port the exhaust manifold, then get a 2.5" crossudner pipe and get it Jet hot coated to retain heat. The larger size will be less restrictive and the Jet Hot keeps the heat in the pipe which keep the pressure up (hot air expands, keep it warma nd it takes more volume). By keeping the pressure up you eliminate alot of the turbo lag which the main complaint with the arb turbo cars.

Also a good 2.5" good flowing exhaust will help make more power.

You can use the stock 32/36 DGEV style Holley 5200 but the primary side needs jets bumped up usually two sizes and secondary side usually needs bumped by two to three sizes.

If it were me I'd also duct in cold air to the carb and sue a K&N airfilter.

It is also recommended to add a water injection setup which reduces the intake charge temp, works like poor mans intercooler.

With all teh mods most boost would be in neighborhood of 12-15lbs depending on where you start getting detonation. IIRC stock is 6lbs.

After motor is broken in synthetic lube is recommended sine this will lower operating temps and reduce friction, making more power.

Just guessing but I dont think 225-250hp would be unreasonable

For $200-$300 budget I would concentrate on super energy coil and rejetting carb.

If you have any money left over get big cross under pipe.

After you bump boost you will need to get a high flow exhuast ASAP to see any real performance.