Panic,
I spoke to Dave Haugen at AERA today and he doesn't have the deck height specs.He will search his contacts and see if he can possibly come up with them.You understand the 270 is an inline and not a V-6.I have attached a link with some valuable information on your project .Feel free to contact me with any other engine related questions.
http://www.6066gmcguy.org/EngineData.htm


In the works 2006 GEN III 6.0 /4L80E/ 205 New process,A/C and power brakes .