Hey,
Just let you know, I just finished a 3.0L upgrade in my 98 SVT (this weekend) using the 2.5L heads. I used the 2004 3.0L short block from Ford. I plan on posting the complete run down of parts used and things I had to do to the block to get it to work. I had to do a fair amount of modification, but nothing a average DIY guy couldn't handle.

Feel free to PM me if you have any specific questions.

I haven't broken it in yet, but it sounds great, much deeper and very very smooth. I put a new clutch, pressure plate and release bearing assembly in that I got on ebay for a very good price and it feels great too.

Marty
98 SVT 3L