I can run a few reasons past you that make the whiplash a good choice.
The 1.92 valve size calls for a LSA that is very close to the listed 109. I’ll have to get to my papers to show what is about the best for a given valve to displacement LSA.
The duration @050 is very good for 3.21’s (I did this before) and better with 3.55’s. To tall of a tire will kill it some.
The lift of the cam is about right in line with Magnum heads. Charlie Servedio’s YouTube channel covers the flow rates of my personal Magnum head.
I do think they have a roller version for the Magnum engine in mind.
I agree. Though a 2200 wouldn’t be to bad with those cam specs. But I don’t know where his converter is from or year so I can’t look it up though I’m sure he did. For his sake, it would be great if it is such the case.
Did you happen to notice the specs of the cam? 218 on the intake. I’ve used an old Crane some time ago (a split duration stick) and used it in a low compression (7.8-1) ’79, 318, 904, 3.21, 1974 Duster rolling on stock tires.
I did manage to find 18 mpgs. Ran high 14’s. This fellas plan is 3.55’s with a bigger tire. If he losses 1 mpg, I’d call it a lot.
But a bonus resides in his favor, the Magnum is a 9.0-1 ratio with a better head. Though the increased cubic inch size may have him in the high 16 mpg range.
The cruddy thing about the Crane I used was the 112LSA. The 109LSA, increased compression, better cylinder head and intake that what I used, being the OEM 318 head with only a valve spring upgrade and a LD4B intake. I used a 500 cfm carb and couldn’t find a difference between the Holley and Edelbrock at this low power level. Typical 1-5/8 headers were used - FWIW
BUT! The 109 LSA will create more torque over the 112 & the higher lifting valve on a better head will add good power. This increase torque below maximum torque found in the mid rpm range will add drivability & mileage.
I also - somewhat disagree on the 3.23 is better than 3.55’s. Having been there and done that twice.