350 Mag engine wake up
 

350 Mag engine wake up
I now have about 60 hours on my Jasper 350 mag and want to wake it up with a cam and set of heads. Any suggestions. Also I thinking about reprogramming the ecu .

Need to talk to someone that has made good running programs for modded 350's and get the parts they used for when they wrote that programming.

If you or someone else is going to tune it on the water ( MEFIBurn is the software one can purchase to do the programming if you have one of the MEFI computers of course.) then many of us can recommend parts depending on your hp goals.

To elaborate what SB said, we'd need a baseline of exactly where your current engine stands in terms of performance, specs and parts.

What pistons/crank do you have?
What is the current compression?
What is your current injector size?

What is your HP goal?

Which ECM do you currently run (MEFI 1, 2 ,3, 4a, 4b, 555, other?)

Do you have a budget or financial number that shall not be exceeded?

put a carbed big block in it.:D

Kind of off subject , but on subject question.

If a 525 SC is basically a 420 with a little blower., what about a small blower on a 350 magnum.

What size blower a250 or a 420. ? And what kind of horsepower you think it would produce?

Just called Jasper Marine and they said they the mercruiser block number OL 316394 for a rebuild.
All the tech said is that is was built to factory specs... The 350 Mag in 99 was a 300hp motor.

I can call proboat to see what they would recommend but I want add a cam and heads to give me 350 or so hp.
They will probably want $2000 to do the work and thats half way to a procharger...

Procharger says that everything is linear so the stock block could take up to 5 psi.

Could not see what ecm I have

'99 350 mag should have vortec heads which are good for up to 400 Hp. If you just want a 50 Hp wake up, a mild cam with around .500 lift, custom tune, and stronger springs with a ghetto grind on the retainers should get you there. But you probably won't even notice a 50 Hp gain.

Spending $12-1500 on a good set of aluminum heads with everything else being stock is not worth it IMO. You'll gain a little on the top end but increasing flow with larger runners will sacrifice torque at lower rpm's, something we don't want to do on a marine engine. It's really hard to beat the stock vortec heads for a stock or mild marine build.

If you want noticeable gains without increasing displacement and you have the budget for it, do a supercharger, long tube headers and through hull exhaust. At that point you also need to make sure your drive is up to the task. By the time you spend that kind of money, you can just buy another boat that has the power you're looking for.

What ?

Don't let the guys with the big and old boats suck you into this thought .

50hp will be more than noticeable on a good running (already) smaller I/O.

My hull's not as fast but I'm in the same age range and weight.

I'd rather have the torque than Hp and, to me, 50 Hp ain't much but I guess that's subjective. My wife would notice a 2-3 mph increase but I don't. LOL When I'm testing it takes a GPS for me to tell if I'm going any faster or slower if we're only talking 2-3 mph. I can't notice a difference between 52 and 54 but I can notice a difference between 40 and 50.

Right now I'm getting 51 at 4700 rpm, I want to get 60 ish...Will a Alpha 1 Gen II take 400 hp ?