DavidB
1/2 ton status
Thanks much guys. The Vortec in question would be a 7.4 (454) 1997 Suburban model.
uberbeans said:It only has to beat the emmisions of the original vin/vehicle. Plus you can't delete/modify any emissions equipment. I would think that you could keep the original smog stuff from the donor vehicle and pass with no problem.
All the compression (leakdown test) is coming out the crankcase (dipstick)
K10A'sBROinSLO said:I don't think the Vortec will bolt in. Not sure. The electrical, fuel supply, and emissions stuff is what bothers me. Need to get on the phone with some experts tomorrow.
bowtiepower00 said:If you run the Vortec injection then yes, you will need to supply HP fuel, and mess with the computer, etc. Also, I believe the ECM on the auto trans models controls the tranny too, so you'll have to work around that. If you're going to keep FI, I'd keep the OD trans too. You could just put a carb manifold on it and run it in place of your current 454.
y5mgisi said:FYI My burb originally had a 400 small block in it. I still had to pass the sniffer after i put the 500 in it. It Passed with flying collors and didnt even have the egr valve hooked up, no cats iether.

bowtiepower00 said:Do they actually check the engine numbers? If not, just build any old SBC, a 400 or factory roller cam block would be nice, and run a Q-jet with whatever factory smog stuff was required. I would think that an AIR pump would be all you need. My 80' K20 has AIR but no cats from the factory. I'm thinking about putting fuel only TBI on it eventually, I think I can hide it pretty well as it only has a couple of sensors and uses the factory large cap HEI. You could keep the 454 too, if you want the BBC. If the vortec is complete, just add cats and drop it in. Fuel delivery will be the biggest issue, running a return line and such, particularly if you are keeping dual tanks.
guess I'll just throw any ole 454 in for now and save for a supercharged 8.1 swap. 
But will it pass smog?K10A'sBROinSLO said:I don't want a big, heavy, slow-shifting bread truck, I want a high-hp, no-lag gas motor and auto for sand and the occasional mud.