Redline rpm for 3.0

[Pearl Beach]

Assuming 3.0 and LX 3.0 are same block, why is LX rated for 4800 max and standard motor only 4600?

 

[Jim Wirth]

LX has different heads than the standard 3.0, so maybe different ports, valves, valve springs.

 

[Lazy Daze]

The non-LX "labelled" 3.0L is still rated for 4,800. However, you may be comparing a much older 3.0L to a slightly newer one. Comparing across different years isn't a valid way to compare.

 

[Pearl Beach]

The non-LX "labelled" 3.0L is still rated for 4,800. However, you may be comparing a much older 3.0L to a slightly newer one. Comparing across different years isn't a valid way to compare.

 

[Pearl Beach]

Number on block:
MII268RA
Sticker on rocker cover:
Max rpm: 4200-4600
130hp.
There has been an engine swap before I owned this boat. Engine ID sticker on valve cover is unreadable, but block casting is stamped as above near distributor. I don't know how to decode this number, so Year is unknown.

 

[Lazy Daze]

Number on block:
MII268RA
Sticker on rocker cover:
Max rpm: 4200-4600
130hp.
There has been an engine swap before I owned this boat. Engine ID sticker on valve cover is unreadable, but block casting is stamped as above near distributor. I don't know how to decode this number, so Year is unknown.

Since you didn't mention the year of anything (you should add this to your signature), I took a stab and was thinking of the most recent Sea Ray "175" which would have been 4,800. If memory serves, on the V6's and V8's, an LX designation meant a 4bbl carb within the same model year. I'm not sure on the 4cyl. Unless you're comparing older with newer, which of course isn't valid.

What you could do is go to an online parts store and compare various years and designations of the 3.0L and see what components are different. But you also run into the issue of "who knows" since it's been swapped - meaning, "who knows what it's been swapped with and how much of the engine was swapped".