Inline dual fours

[Gaz64]

Originally Posted by Zoom This

I believe that any motor with a high lift cam and long duration will never pass a smog test. Motor is way too lumpy at idle to be clean. I had my 418W sniffed by the smog police when I lived in California (a requirement for record purposes only) and was told that at 2500 rpm the motor was clean enough to pass as a 1965 Ford. At idle I was told that I was a gross polluter. The best you can do, in my opinion, is to set the carbs so the motor runs at its best at idle, transition to the high speed circuits, and full throttle. If you are required to clean up the motor to pass a smog test you could have trouble. Has your car been on a chassis dyno with a sniffer up the exhaust? Your plugs will always tell you what's going on inside your motor. Clean up the plugs by proper jetting and you're good to go.

All good advice.
High rpm cams will not pass emissions with carbs, period.

Sequential EFI or milder cam with less overlap.

I'd be throwing the 1850s in the bin, fit a pair of 600 Edelbrocks.