Sorry for the confusion. I was talking about the gearing and cam in my 340 Duster when I said I didn't want to tow it with my 318 D100. The 318 has Speedmaster heads on it. The gear in the Duster needs to be somewhat highway friendly (65mph?)
I'll proceed with the Z and O 1.88 cylinder heads that are on the 340 now and just keep an eye out for a deal on some W2's. Meanwhile I will be reading a lot about them.
