Bought my first mopar 73’ Duster and the bottom of the air filter pan is black (right above the carb). Any tips on how the 4bbl should be adjusted

Thanks for all the great info. I guess I'll need to find where I put my compression kit. I bought it from a guy I believe was the second owner. He's had it for 10 years and was in his 70's. He kept every receipt and had 100's of spare parts that he'd pick up wherever he went. He only drove it to car shows so he put on less than 200 miles a year. Spent most of the time I believe in his heated garage. So I think the car was well cared for before me.

I should've browsed this forum more because the engine block number was extremely easy to find. It's a 318. The original owner looks to have put a few factory 340 stickers in the engine bay and removed the Duster emblem in the rear to replace with a 340 twister sticker. Looks to be numbers matching for a Gold Duster except the 4bbl carb and Edlebrock manifold. Also opted to remove the bench seat and put Bucket seats in. It sounds great but it doesn't quite sound cammed to me (though it very well could be).

I'm going through the plugs this weekend. Didn't notice any smoke or issues yet. Drove it for about 45 minutes. It is an automatic. It was converted from the column to the floor (they saved all the parts). When I went over to test drive it the first time the tumbler in the ignition locked up. He had it towed to a local performance shop and I believe they put a whole new ignition in but I need to doublecheck the bill.

Your last sentence hits home because last year I was working on an 87' Monte SS trying to get the idle speed correct with a friend who is a full time mechanic. Almost put it right through my garage door.