To answer the question....... as best I can.......
I havent used that Lunati cam, but it looks like a suitable choice for the direction you’re trying to go.
I also agree that for operating range you’re running the motor in, 200/500 springs loads should be plenty.
To put my .02 in on things that weren’t asked.......
for that operating range, I think the MW sized ports and manifold were a mistake....... but you have what you have.
Even at 500”, they’re likely tuned for a higher tq peak than 4800.
(I realize the choices for MPI BB Mopar intakes is pretty limited. Looks like there is a std port EFI Victor though.)
I also feel the 2.25” primary is too big for the operating range you’re targeting.
If you could have whatever you wanted, considering the size of the heads/intake...... I’d have gone with 1.875.
Thanks fast68plymouth for the reply. Funny now that you mention it, Hughes was the one who recommended porting to MW in order to move the TQ up on the dinky cam, so I had him strap them to his CNC machine before shipping them. But after reviewing a couple graphs with the Lunati cam, it appears the porting don't hurt the 4000-5000 rpm TQ, in fact a little higher than say the RPM head graph I looked at...but that could simply be a difference in the dynos and testing conditions.
I thought the 2.25" was too big as well and specified 2" on the order, but the Hi-Tek aussies assured me that the 2.25" will yield the most power due tests they performed with a Mercruiser 496 HO (a mild mannered Chevy based engine), and I gave them the benefit of the doubt since I've learned that marine exhaust systems are much different than a dry system on land, plus they've been building marine headers long before I built this boat. The reason why Hughes specified the dinky cam was due to the short length of dry risers that were originally on the Hi-Tek headers when I purchased them off the shelf at CP Performance, but since then I TIGed on an extra 9" section of jacketed dry-pipe to ensure that water reversion won't drench the O2 sensor. When I talked to Hi-Tek about the dry-pipe I added, they assured me that I can run a much larger cam than I am running now and are incorporating the long riser on the 2.25" custom set. At any rate besides Hi-Tek, I've talked to CMI, Basset, Stainless Marine, Lightning, and a few SMEs such as Alex Haxby @ Haxby Speed and Marine, and they all agreed that the 1.75" headers are holding this motor back, and I'm likely to gain at 4500 with the header being the only swap.
FYI, after the exhaust mixes with the cooling water at the end of the risers, the exhaust goes though 4" Hardin transom tips equipped with salisbury flapper valves. I've also added a pair of 4" stainless Flowmaster 854040 Super 40 Delta Force mufflers, outside the transom to tone down the bark into a mellow tone...and they do so with no negative affect on performance according to the Holley datalog. Most marine mufflers are nothing more than very expensive stainless steel taters shoved into the pipe, which drastically cuts down WOT rpm.
