the evap has a temp spec of like 40-50 or higher before it will test, and 1/8 to 7/8ths of gas.
alot of people are going to ls based engines, if you got the money the car ones with a t56 trans is a great upgrade. but the cheapest are the 2wd 4.8 and 5.3 truck engines with the 4l60, these are getting real cheap and in a car its over 300hp and over 20mpg sometimes mid to high 20'*. only downer is you need to have hpt or some tuning software to make it all work together. you can have the pcm sent out and done for you but for what they charge it seems more reasonable to just buy the software for yourself. i am sure that even if they want to plug in to your obd2 port on the swapped engine, with the tuning software you can make the IM monitors look good even if those systems were not swaped
1998 Bonneville SSE
2007 Monte Carlo LT-KYB, Clarion, Polk audio, Kicker
1999 Yukon SLE-KYB, Air lift, Reese dual-cam, Tekonsha
1987 Firebird-355/th400-nothing stock