1993 7.4L Mercruiser / Bravo 1

[FuelishBehavior]

I'm going to attempt to build a mild replacement engine for my boat and I'm gonna mirror my current gen V mercruiser 7.4L. I've already found block and heads. My question is, does the current engine, the Mercruiser, specifically the cylinder heads, use "inconel" valves or are they just severe duty stainless steel. I intend to build basically the same engine between 300 and 350 horsepower. Maybe even stroke it.

 

[tpenfield]

Re: 1993 7.4L Mercruiser / Bravo 1

I am not so sure that the valves are any different than the truck versions of the 7.4. IIRC - the Gen V did not have self adjusting valves, which is a bummer.

You would have to verify the deck height to see if you could 'stroke' the engine. . . . and you would need a new crankshaft. Most often you will find those engines 'bored' not stroked. If you have or can find the 'rectangular port' intake and heads . . . that will do the trick versus the 'oval ports'.

 

[FuelishBehavior]

Re: 1993 7.4L Mercruiser / Bravo 1

Stroking it isn't really high on my list. I just want to build a replacement for my 7.4L/Bravo 1 with maybe a few more ponies...nothing huge. It's currently 300 and I'm looking at 350 as my goal. I'm really just wanting to get the torque higher honestly. So when I build the cylinder heads, I just want to make sure that severe duty stainless steel valves will be sufficient. I just want to build a nice, reliable, balanced and blueprinted engine over the winter.

 

[Bondo]

Re: 1993 7.4L Mercruiser / Bravo 1

I'm really just wanting to get the torque higher honestly. So when I build the cylinder heads, I just want to make sure that severe duty stainless steel valves will be sufficient. I just want to build a nice, reliable, balanced and blueprinted engine over the winter.

Ayuh,.... Strokin' the motor is where more Torque is found,...

Big valves, 'n free flowin' heads give more top-end horsepower...

Though as Ted notes, the peanut port heads run outa power 'bout 330 hp or so,...
If heads, 'n intake are in the budget, square ports are the way to go...

Find a local Machine Shop, 'n talk to 'em about what yer lookin' for,...
Tell 'em ya need a Gutsy motor for a Big dump truck,...
That's what a good boat motor is,... A Truck motor... Power from idle to 4800 rpms is Ideal....


Btw,... Blueprintin' is an ole 60s term that really don't mean squat...

Balancin' on the other hand is time, or money, very well spent....