1980 road bike vs 2008 TT bike

it will help a ton... if all you do is ride on flat ground.  TT bikes are not designed for climbing hills, therefore it will be more work on a hilly course than the old road bike.  i am jealous of both though, i have done several tri's just on a mountain bike.... ya know poor college kid syndrome!

The last triathlon I did was in the early 80's and I had a nice (at the time) Univega. After I dusted it off and replaced a few things like tires, chain, and everything else that had deteriorated over time. I was ready for my comeback.

At about two months into my cycling I was able to cruise along on flat surface at about 16-17 mph for about an hour. My wife is training with me and she has never done anything like this before. She was using her mountain bike and really struggled to keep that pace for any length of time so I bought her a Quintana Roo Tequilo. She than chuckled as she followed me because I had to pedal so hard and she just glided along. After a comment from her about my bike having square wheels or something, I bought a Quintana Roo Lucero (all carbon). I think I got the last laugh.

Bottom line, on the 80's road bike I was riding at 16-17 mph and with the same effort I'm now riding at 19-20 mph. The comfort is also much greater. The P2C will be amazing compared to what you are riding.

The other issue is fit - bikes have indeed progressed quite a bit in the last quarter century, but if your current bike is too small, you are not getting all the leg motion and body position advantages that you will find on a bike that fits. Plus I would think the old bike uses friction shifting.  (My wife's old bike that she refuses to part with has friction shifter on the top tube).  Not having to move your hands off the bars and fiddle around to get the right gear will also pick up your pace quite a bit.

Thanks for all the insight. I'm really excited about starting to look for a new bike. I'm thinking of going to Cadence Cycling in PA on my bosses advice for my bike fit.

Definitely get the fitting done.  But also realize that the benefit of the TT position is that it saves your legs for running.  It is much easier to run off of a TT bike than it is a road bike.  Bike weight and geometry aside, the TT position will also reduce your "wind profile".  This won't be much of an issue for shorter races, but the more time you spend on the road, the more aero matters.