i jusst bought a 1984 z28 for 1200 bucks. all i know is the car has a 350 that came out of a truck a comp cam 260 edelbrock rpm intake edelbrock 600cfm carb,heddman hedders flowmaster muffler, 373 gears and for some reason theres mildly ported 305 heads. i took the car to the local dragstrip and it only did high 17s at 89 miles per hour spinning tire. im sure the heads are killing me but what other mods would help me. the pistons and carnk are stock

 

the heads are probably #601 heads, which would be 52cc chambers to raise compression and drop volume. Or #416's with 58cc chambers as apposed to the 64cc that come on 350's i believe, which would also raise compression. If you have a misfire, you will make the difference between 13 sec and 17 sec. Also if you dont have enough backpressure you would get a horrid start from that setup, but it seems like you would have plenty.

The Edelbrock RPM intake and carb should be fine, unless the carb needs tuned or rebuilt, if the secondaries aren't opening your moving less air and fuel, resulting in poorer times, or if they are opening to early. Check for vacuum leaks, they can bog, stall out, and cause poor drivability.

The cam may be too big or too small for the car, It looks to me like it might be big, I think that setup would like more of a .3xx/.3xx dur. But I am far from an expert at cams.