Not how I wanted my intro post to go, but I'm stumped on a cam question and figured I'd better ask the experts...
BLUF: Should I even consider a reverse split duration cam on a 318 roller build with Magnum heads?
I'm working on a roller cam 318 LA build from an '88 Fifth Avenue that I parted out. The plan is a bigger roller cam, EQ Magnum heads with stock valve sizes, a '71 340 intake that I picked up, and a rebuilt mid-80s Chrysler Quadrajet. This will all be going in my 3000lb manual everything no-A/C Volare daily driver. I'm looking for lots of mpgs with something that will still merge with traffic and put a smile on my face.
While perusing cam choices, I came across the Lunati 20200714. Unfortunately, sometime in the last few years since I bought a cam, it seems that all of the manufacturers have taken down cam cards off of their websites. I don't know why, but used to you could open all the info straight up from the product pages at Comp Cams or Lunati. Now they give you the pre-school numbers and leave the rest up to a call to tech support.
I figured I'd google the part number and see if I could find a cam card. When I did, the first hit was an Amazon Prime listing for that same Lunati cam part number for $140. I figured for that price, it was worth a shot to see if it was real or not, and potentially get a roller cam with specs that I liked for half price. You probably know about where this is headed now...
For reference, the cam page from Lunati is here: Voodoo Hydraulic Roller Cam - Chrysler 273-360 (W/ Long Snout) 258/264
It lists 207/213 .485/.485 with a 112LSA and 106ICL. Assuming those lift numbers are at 1.5:1 ratio, because it doesn't say.
Well, the cam came in today, and it is a brand new Lunati roller cam. The cam card part number is 20200714. So far so good. The number stamped into the back of the cam is 20200714. Even better. Then I looked harder at the cam card, and noticed something interesting...
View attachment 1715401773
Although the part number is the same, this cam card lists a 213/209, .480/474 on a 112LSA and 106ICL...
What gives? I would think if it was a custom grind, it wouldn't be carrying an off the shelf part number. I searched these cam specs and came up with nothing, so it's not some other grind that got mixed up. Either its a cam card typo, a custom grind with an OTS part number, or somebody botched the cam grind and boxed it anyways. I plan to call Lunati tech support tomorrow to see if they can answer those questions. I'm guessing this is why it was $140. I checked today and the price was $300 on the same Amazon link now, so maybe they were just trying to dump a botched grind on an unsuspecting customer.
Now, on to the meat and potatoes of the post...
Is there any merit to trying a reverse split duration cam with my build? It seems like there are a few posts here and there where certain individuals recommend a single pattern cam, or even a reverse split cam with magnum heads since their exhaust ports flow fairly well relative to intake flow. That makes sense, and I might even buy it with headers. Only problem is, given the extreme budget nature of this build, I had planned to run scrapyard magnum exhaust manifolds and save the header cash for gas money. So is it worth trying this thing, or should I go through the hoops to return/exchange it for the grind I really wanted (while probably paying twice the price in the process).
Thoughts? Opinions?
