75 Spider 1800 2000 engine parts swap for +BHP

I am trying to decide what parts to use to build a stronger 1975 1800 engine. I just bought a NEW 1800 complete short block for $500 and I am confused about what head to use? Do I stay with the original head and just get it rebuild and add a performance cam, dual 40 Webers, and a free flow exhaust, or do I put on a 2000 head? I know where there is a ported and flowed 2000 head for about $350 and although I was not planning on getting this head, I was not sure if the 1800 and 2000 heads give the same compression and flow. I will take any suggestions. I am new to a Fiat and so far I love it. Since the car will be a daily driver, I have decided to make the engine, suspension, brakes and electrical like new.

You would lowere the compression ratio by using the 2 liter head...

John R. Rushton
79 Spider 2000
my place http://pub79.ezboard.com/bfiatcenter

One easy way to produce more hp, since you seem to have access to the parts would be to use a 2000 block with an 1800 head. The added displacement comes from a longer stroke, so you may see some added compression as well as hp. The top end of your rpm range will be slightly lower ( 200 ?) but with the power gain you may see it as a good trade off. good luck!
John