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Thread: Opinions on this camshaft please

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    98Dak408's Avatar
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    I tend to be a little more conservative for daily drivers since people tend to over-cam their engines. The cam explanation in regard to operating rpm is called out for a 360 engine. That same grind in a 318 will act as a larger cam and in a 408 as a smaller cam. If you truly want low rpm torque then I would consider either the HPT218XR, HPT220XP, or HPT224XR. I initially ran my 408 with the HPT220XP on a 108 lsa which moved peak torque to a lower rpm, which helps get a heavier vehicle moving. A wider LSA on that same grind would be a broader power band and produce a little more peak hp, but not have as much peak torque down low. This HPT220XP produced a lot of low rpm torque in my 408 but was pretty much done around 5500 rpm (the engine is still producing power past 5500 rpm but at diminishing returns). The following are a couple of vids with the HPT220XP on a 108 lsa:

    https://www.youtube.com/watch?v=z-P4QgaT25k
    In-cab opening exhaust cut-out

    https://www.youtube.com/watch?v=PbkwFjqnzfE
    Outside cab with open headers.

    A wider lsa will help smooth out the idle and create more engine vacuum.

    I currently have a customer’s 1997 Ram to produce items such as an x-brace, front and rear driveshaft loops, panhard bar, etc. He is a running what amounts to a 224 intake duration on a 114 lsa since I believe he is considering a blower. It too has very good low rpm torque and a broad power range.

    So if you want low end in a 408, I would consider something around 218-224 intake duration.

    However, if you are going to run a 1.7 rocker, that usually puts the lift higher than can be accommodated by the engine without more serious work being done to it. You are better off with a 1.6 ratio since there are more available cam profiles for it. If you are insistent about using 1.7 rockers, I can try to put some specs together that will keep the lift to a reasonable level. However, for instance, the HPT236XFI is a great cam but not for low rpm power. With the 1.7 rocker ratio, the lift would be .615/.612 and .579/.576 with 1.6 rockers. The Eddy springs are good for .580 lift.

    Note: You should always check your clearances to be sure, at the very least, that you didn’t miscalculate or screw something up.
    Last edited by 98Dak408; 10-11-2016 at 01:55 PM.

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