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· Founding Member
6,741 Posts
Texas has basically the same rules. The assumption is that emissions have been improving year by year and so an engine from a newer model car should pollute less than the older original motor that you are replacing. For instance, you can put an 87 mk3 turbo motor into an 85 mk2 chassis so long as you also transfer the ecu and smog equipment that was in the 87. Then you have to pass the standards for tailpipe emissions that were set for 1987 and not 1985. What they frown upon doing is putting an older motor into a later model car. I can't think of a Supra example, but for instance it is very popular among the 79+ Fox chassis Mustang owners to install a simpler and much more powerful carburetted 351 windsor motor from a late 60s to mid-70s montego/torino/LTD etc in place of the 255 or 302 V8 motors they came with. They also further restrict you to engines from the same class of vehicle which basically means that you can't pull that 4.7L v8 out of a Tundra pickup and drop it in your mk2 even tho it is newer because trucks are held to a lower emissions standard than passenger cars. The 6m engine that is so popular for mk2 owners is technically not legal since it was never certified for sale in any vehicle in the US. However, since they are externally identical and will pass the tailpipe test so long as all the 5m EGR equipment is transferred in the swap, then they are overlooked. I've never seen anyone post a problem getting a 6m past smog in the 7 years I've been on the SOGI and mk2 lists. Hope that answers your question.

Phil D.
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