454/425hp mercruiser
 

Hi everyone,

Have 1990 Baja 370es from 2012 with twin Mercruiser 454/425hp ''performance series'' for this year,
this week need refresh engine but i think both engine have already been redone but don't think with original parts !bore .020, have head casting 14096188, roller rocker 1.7, hydraulic lifter, intake is not original seems like air gap because clear 3'' under (carb), carb holley 850 dp, camshaft B&M 3646 ( unable to find specs for this camshaft !) but when i bought this boat there were 2 gauges as if he had already had blowers !!

Question : this is the right set up ? beacause need to replace camshaft and lifter (broken)

Thx for reply !

Engines may have had blowers at one time and that cam might have been purchased as package from B&M.
Heads and roller rockers are correct. Stock carb was a Holley 800cfm.
Stock cam for the Merc 420/425hp engine was a Crane 132561.
Crane is out of business, but here are the cam specs Crane Cams 132561 H-228/312-2S-14 T1.2 Camshaft
I would upgrade to roller cams though. Flat tappet cam's of today are junk and 50/50 if they break in correctly. This would be a good choice Teague Custom Marine | BBC Mark IV Billet Camshaft - Stage 1

This!!

And even if they do break in correctly, the risk of failure later is still a factor.

OP, you said a lifter was broken? Depending on what you mean, you could be looking at a bigger issue (a worn lifter/wiped cam lobe means a full rebuild… metal will be everywhere).

All engine disassembly and all cylinders are perfect, crankshaft perfect, pistons set perfect, no issue other just 1 lifter and lobe camshaft,

as i refresh, bearings, seals, rings set, oil pump, new lifters, and cam, would there be a possibility to increase some HP with a hotter cam?,
i have a HI-Rise aluminum intake manifold, head 14096188,

If you don’t use a roller camshaft, you’ll be rebuilding it again.

Griff already recommended a cam.

The cam I recommended is the same spec as the old Crane 168731 and is very similar to the 500efi cam. I wouldn't go much bigger for your boat. You need the low end/mid range torque.

So I would have no advantage in installing roller lifter?

That is a roller cam that he suggested.

There is always an advantage to going with a roller lifter over a flat tappet.

Originally, the idea was that there would be more power for the given lift and duration compared to a flat tappet, but these days, the primary advantage is around keeping the engine together.

The cam that Griff referenced is close copy of the Crane 168731 used in the Merc HP500 502. The 168731 cam did have some issues with reversion so if you go that way, make sure your exhaust is up to the task.