the 2600 was the mistubishi motored (and carbureted) 2.6 made in 87-88. The 2600i was the fuel injected Mazda 12valve 2,6 made from 90-93 (a few 89's). To tell the difference, look at the cylinder head. The exhaust manifold will be on the passenger side of a 2600, on the drivers side of a 2600i. Also, the valve covers on the 2600i will have "12 valve" cast in them on the 2600i.
I have seen a one 2600i without a bubble hood, but it was because the truck had been wrecked and the hood had been replaced. I had one that was a 90 (late 89 production) and it had the bubble hood, two others ( a 91 and a 92) had the bubble.
I always assumed all 2600i had the bubble, nice to learn otherwise. As its been mentioned, the flat hood fits the injected motor just fine, so if you find a 2600i bubble with the same color as yours........ hahaha
I was at Tenkiller lake a few weeks ago and right outside the lake on 82 there was a 4x4 std cab reposing in the back forty of a repair shop. Thought about stopping and seeing the deal, but didnt. Heads up to all you OKIES.
i thought the bubble was on the 4x4 2600i only and the 4x2 was flat the years mentioned above? either way ive got my hands on only 2 hoods, one is good and the was in a wreck, but i kept the hood ne ways to cut out the bubble after i wrecked it.there geting harder and harder find.i found a 93 2600i ext cab last week for $900. if the guy comes thru im geting it for $700.