since ls motors naturally fall off after 5000 rpms or so. what would the first steps be to help breathing capabillities without drastically altering geometry, ildling, and other things? could you get a port and polish and use stock cam, etc.? havent come across much info on this. any insight is appreciated

 

Take a look at this dyno graph:

http://forums.evans-tuning.com...=402t

I'd call that a dramatic difference in breathing capabilities. Take note of the parts used.

 

Search search search. there are plenty of high HP LS mills out there

 

ls heads dont fall off at 5000k... they drop off after about 7200k if you want to be able to rev higher to about 9k i would go with a good set of turbo cams and at least do a mild p&p to the head because after i did that with my setup after 7200k it just went up and didnt drop off until about 9k but the power went up and stayed steady and also upgrade your springs and retainers i will try and scan my dyno graph and post it up for you