I just installed a new HCR Head and Im getting gas under the head and not starting what have I done wrong ,,,,,This is on the 2.5 on my T-Maxx

What do you mean by gas under the head?

when you replaced the head did you replace the head shimms ???
if not this is why you are getting GAS under the head as it isnt sealing to good
if not thier is a good place to start also if it is a bigger head you will need to adjust the carbie settings
hope this helps a bit