I’m new to boating but not to engines. I have a 383 Mag Stroker that is unmodified, but was wondering if it would accept a COMP 218/224 cam without other upgrades. So far, technical details are hard to find. I found the part number for the valve springs that come in the engine, but no details about them. Does anyone know if the MPI 383’s valvetrain is built stout enough to handle a cam like this? Thanks!

Carb or EFI?

You would need to run wide band to check AFRs and modify the fuel tables if EFI. That would be your biggest hurdle. That cam, without knowing the LSA or lift, is likely not going to give you any noticeable improvements for the amount of trouble you will have tuning the motor if it has a Merc 555 controller.

Ayuh,..... The thread title says MPI,.....

What are the specs of the current cam

So I don’t know the specs of the current cam other than .497 lift on both intake and exhaust. The COMP cam has .495/.503 with a lobe separation of 112°. It’s actually meant for a 305-350 with an operating range of 1200-5200, so it may be on the small side for a 383. I’m just afraid of putting too much cam to it because I know it’s not as easy to get away with as it is with an automotive engine.

Not exactly sure what your plans are, but if this is a marine motor with water jacketed exhaust manifolds, you need to be careful with cam lobe overlap, because it can cause reversion where your engine will suck in exhaust water... Obviously this isn't a consideration on automotive engines. I'm not exactly sure what the limits are for overlap before reversion becomes a problem, but I'm sure lots of people here could chime in on that.

As Trash mentioned above - not worth it.

Enjoy it for what it is.

then....... its a 3/4 race cam for you.

Assuming the stock valve springs can take it with no coil bind, And you have the clearance under the valve covers, And there's no issue with piston to valve clearance, ..it would be faster and cheaper to just upgrade the rockers to a 1.6 ratio from the stock 1.5
That would increase the lift up by about .030. So in essence you would be getting a higher lift cam without actually changing the cam..

Not worth it. It would have to be re mapped as well.