The engne is 5.0 litres (307 cu in) LV2 V8, 140 hp.
As others have suggested, better intake, cam, a bigger carb, and dual exhaust will go a long way toward waking that 5.0 up, but if it were me, I'd find a 5.7L LS engine from a more modern vehicle, swap it in and be done with it. The 307CID V8 isn't the best platform to start with for a performance motor. But, with the right speed parts, you can get decent power out of it. But an LS series would have a lot more potential.
Anything you do might move the power band one way or the other, but you are not going to make this mid-eighties engine a high performance engine. In that era a lot of American cars were severely choked down by smog equipment. Their power was cut in half or more.. Star with a better engine and adapt it to the car. Still, it's just a big, sloppy Cadillac that could hardly make the speed limit when it was new when you used the air conditioner.
Get a new carb, intake manifold, headers and a cam.
make sure to match the headers with the cam you intend to use ( lenght depends on duration and rpm of the exh lobe.
I would replace the carburetor and intake manifold and maybe the exhaust too.
Give it a good tune up. Replace all plugs with OE AC/Delco plugs with the correct number for your engine. Also replace plug wires with OE spec [7mm or 8mm] wires. Clean the throttle body with a chemical cleaner. Drain and change the auto trans fluid and filter. Change the fuel filter. New OE spec air filter, don't waste your money on K&N etc. A Fram or Delco or similar will do just fine. Add a couple of plastic cans of Techron fuel additive to the tank. Techron is cheapest at Walmart. Change the engine oil and filter. Suction out the power steering fluid with a syringe and replace. Do this a couple of times after driving to get a good mix of new fluid. Also have the brake fluid flushed - it out-dates every 24 months. Then enjoy driving grandpa's car the way GM intended. Quiet, smooth, slow.
Nothing you do to it will make any noticeable difference. Don't throw your money away on it.
You can do wonders to get the HP up but in the end you have a old lead sled Cadillac.
The car is a 1988 Cadillac Brougham
The engne is 5.0 litres (307 cu in) LV2 V8, 140 hp.
