1993 Chevy Silverado Strange rev issue

350ci silverado. For as long as I can remember I have had strange issues with my truck's rev; there is no tach so I cant accurately say where my truck stops revving, (i dont know if there is a rev limiter, but if I had one it does not bounce off of it) but it seems that it will not continue to rev if I hold down the accelerator while in park. If I hold down the accelerator steady it will act as if I let off and it wont rev right. I feel really stupid asking the question like this, but I don't really understand why my truck is like this or if anything is wrong. The truck will also misfire at idling and surge when the accelerator is held steady while driving. I have an aftermarket intake, an airaid tbs, bwd dist cap and rotor, bwd icm, holley map sensor, accel plugs, accel wires, duralast iac valve, bwd engine temp sensor, msd ignition coil, jegs headers, airtex fuel pump, wix fuel filter. Much of these parts have been an attempt to repair the misfire, but no luck; maybe my rev problem is related.