ticking noise and down on power...help

Ok, my car is actually not a mustang, it is a 91 cougar, but it has a 5.0 in it, so hopefully someone here can help. The motor is out of a 95 mustang GT and I swapped in a B-303 cam and GT-40 heads, bypassed the smog pump, and deleted all the A/C stuff. Here is the problem. There is a ticking noise that sounds like it is coming from under the passenger side valve cover, and the car is seriously down on power. Also the oil pressure is kind of low when idling (15psi in gear, 20psi in neutral) but comes right back up as soon as I get on the gas. I clocked my 0-60 yesterday with a stopwatch, and it was about 10 seconds. Considering it was 8.1 when the car was completely stock with 200,000 miles on it, it should be much faster than it is. Also the car is not producing a lot of vacuum. It gets about 10" at idle out of gear, and about 5" stopped in gear. I don't know what the bcam is supposed to pull vacuum-wise, but I get the feeling it should be more than that. Anyone have any idea what is wrong with my car? Thanks.

Mike

Well the original motor is gone and this one only has about 65000 on the bottom end. The rocker arms are stock ones for a 95 GT. They are not roller rockers, and when I put the heads on I torqued all the rocker arms to 22ft-lbs. so I don't think they are causing the problem, but it could be. The ticking noise happens all the time, and gets faster/slower with rpms. The car does start and drive every day, and I have put probably 2000 miles on it since swapping everything. It also gets pretty bad gas mileage (like 13mpg average) but I don't know if that is to be expected because of the cam that is in it. What could cause it to be this down on power? It's just painfully slow. I've messed around with the timing but I can't get it any better. As soon as I advance it more, I start getting detonation (running 93 octane gas) but the power is still pathetic. I don't know what to do next. I am tired of tearing this thing apart then putting it all back together over and over again and still having the same problem.

Well, I didn't rotate it when I tightened them. If that causes the symptoms that I have, then I'll pull the valve covers off and adjust the rockers. Thanks for the help. Hopefully this will solve my problems. Would that cause me to be down on power this much too?