Depressing Dyno results. Need advise

Before you start throwing expensive pieces at the car, do some detective work and find out where your problem really lies. You can do most of this yourself with a few basic tools and a couple test drives. Don't give that dyno shop any more of your cash.

Tools: Get a timing light, a vacuum gauge and possibly a fuel pressure gauge. You should be able to get all 3 for under $100, and you'll need these to do any sort of tuning. Oh, and a stopwatch.

Fuel delivery: Replace all rubber lines, especially anything on the suction side of the pump. Pull the pickup out of the tank make sure the sock isn't clogged with crap. A decent mechanical fuel pump will do fine, a cheap Pep-Boys special won't. Go electric if you want. 5/16" line should be OK, but the factory used 3/8" on 440 cars. If the line itself is in good shape, it's probably not your problem.

Test drive: Set the timing to something sane like 10 BTDC and leave it there for now. Make sure the FLOAT LEVELS are SET CORRECTLY on the carb! Splice the fuel pressure gauge in the line between the pump and carb. Where the fuel filter was is a good place. You want a long enough piece of line on the gauge so you can tape it to the windshield and watch it while driving. Start the engine and note the pressure. Now drive around nice and easy. Pressure steady, no leaks? Find a nice quiet country road and floor it in 2nd or 3rd until it breaks up. How's the pressure, does it drop off? You'll see a little drop, but if it goes below 3 PSI, you have a fuel delivery issue. If it stays around 5 PSI look to valve float.

Valve springs: When you say stealth heads, you mean 440 Source aluminum heads right? Not sure what springs they ship these with, but they should be fine with that "mild" cam. In fact an OEM 440 spring should do OK. How does that "custom" cam base circle compare to stock? Lifter preload?

Cam: Bear in mind that a stock 440 cam had about the same .050 duration, and similar lift. Therefore you can expect similar power/RPM with the cam you have now, but less low RPM torque, and a rougher idle. That said, 350 HP, 5000 RPM at the wheels would seem more reasonable. Who knows what the numbers that dyno shop would show. 14 seconds on a country road quarter mile would be ballpark.