Camshaft for mercruiser 383

[Offthepath]

It looks like we will be replacing the engine in our boat this winter. I am weighing the options of how to proceed. One option is to rebuild the current 350 Mag MPI into a 383. Due to very limited tuning options, I want to basically recreate the drop in 383 offered by mercruiser.

Can anyone tell me what cam the mercruiser 383 uses, or the profile so I could select a similar aftermarket cam. Is it the same cam as the 350 mag?

Thanks

 

[tpenfield]

Don't over look the ECM re-programming or replacement, in addition to the cam.

 

[Scott Danforth]

It looks like we will be replacing the engine in our boat this winter. I am weighing the options of how to proceed. One option is to rebuild the current 350 Mag MPI into a 383. Due to very limited tuning options, I want to basically recreate the drop in 383 offered by mercruiser.

Can anyone tell me what cam the mercruiser 383 uses, or the profile so I could select a similar aftermarket cam. Is it the same cam as the 350 mag?

Thanks

first, why duplicate the poorly built motor that mercuiser built. same cam as the 5.7, just different rocker arms

for the cost, you can build a much better engine that not only has forged internals, however will spin 6000 RPM all day without a hickup

 

[Offthepath]

Thanks I thought it was the 350 cam.

The engine build is limited because I have the Motorola ecm. Although you could easily build a bad ass engine, without options to live tune it, coupled with the fact only 1-2 places in the country offer tunes for the 555 ecm, it would likely be a crap shoot if you could ever get it to run right, or to it's full potential.

If I go this route, I would reuse the cam and add 1.6 roller rockers so I can just use the 383 tune and ensure it runs right. I would however keep a tight quench with d-dish pistons, but that would be the extent of the build.

I just need something with more torque and some more HP. Its a family boat used for water sports, so this engine would be just fine.

 

[Scott Danforth]

your change to proper pistons over the GM flat-tops will require a re-tune
a change to anything in the combustion mix will require a re-tune

so.....there are sources to re-program the 555..... start with a call to them, then plan the build

or upgrade to the MEFI-4 ECM

I personally would be tempted to say go to a carb and abandon the choking TB, the inefficient intake and the inability to tune it......... a pair of 383's can put out 450hp each all day long with 750 CFM holleys on top