I have just fitted a new Antec PSU and the problem is that the chip is located next to the intake of the PSU, so its drawing air from heatsink and chip. However, the temperature of tbird has risen to 65oC from 53oC. All I want to know is this a safe temperature? Or do you think I need a new heatsink and fan?

The only thing i can think of is the intake fan on your PSU is affecting the flow through the CPU fan,antecs do move alot of air.
65 degrees is a bit high,,in fact real close to too high.
i would thing getting a more powerfull CPU cooler/fan would help with your problem.
good luck

Ya could try a bit of ducting from the CPU fan to the outside of the case. That way it gets cool air, and it's not robbed of air by the PSU.

Remember that T-Birds run extremely hot, even with decent cooling. although 63 C is hot, it is still safe for the t-bird. In fact, the t-bird can operate quite normally at 75 C, provided that is an accurate reading.

If you don't mind spending the money, I'd definately suggest getting a higher quality heatsink and more efficient fan for that tbird, just in case that temperature reading is inaccurate.

If you are someone interested in case modding, a simple mod to improve airflow is to mimic the P4 cooling standard for cases. Drill ventilation holes in the case side panel above the CPU, and put a funnel over the holes. This will allow the cpu fan to draw air from directly outside the case.