X-heads / 6 Barrel combo porting

Decent numbers on the heads!

I'd be careful with the cam if you're going to run 3.55's, especially with tall rear tires.

I ran 3.55's in my Duster for awhile, with a larger cam than what you're looking at, and 26" tires. I went with the 3.55's because with the 26" tires that was about the best I could do and still manage decent freeway speed without running around at 4k+ rpm all the time with the 833 4 speed I was running. Anyway, the 3.55's and clutch slip to take off got old after not very long at all. Sure, if you drive it like you stole it and drop the clutch at 3k all the time it's fine, but that doesn't exactly work in traffic.

Anyway, my set up is with a stock stroke 340, .060" over, with a Lunati HFT with duration @ .050 (Int/Exh): 234/242; Gross Valve Lift (Int/Exh): .513/.533; LSA 110. Lunati recommends 3.73's, all I can say is I'm a lot happier with my current 4.30's, 27" tires and T56 Magnum. Advertised RPM range is 2200-6400, I think 2200 is a little optimistic. Below 2,500 there isn't a ton of power. Over 3k and she's a beast, pulls all the through to 6k+.

Compression is 9.8:1 with 308 heads, ported and flowing what you see below. Just the intake side, I don't have the exhaust numbers

So anyway, long story short if the plan is 3.55's and any rear tire 26" or taller you want a smaller cam than what I run for sure, unless you like pedaling to get it going.