Rebuilding a 454 74L have some silly questions

"My stock 454 has about 175 ho

"My stock 454 has about 175 hours on it, the engine is also 14 years old. I am looking into the following rebuild and would like some opinions on the path I am choosing.

Keep the stock short block(great shape)

Remove the small oval port heads and replace them with aluminum large oval port heads. (thinking about edelbrock marine heads $1600)
I already have a new edelbrock alum intake and 750 carb. I will also be switching to fresh water cooling to protect the aluminum.

New cam and complete MSD ignition system.

My main objective is to go from 330 HP to around 380HP.
Now heres the silly question, can a set of auto aluminum heads be used instead of marine heads?
This will be a freshwater/antifreeze cooled engine.

Thanks
Andrew"

If you keep it in fresh water

If you keep it in fresh water why not knock off some more weight and use alum. exhaust mans. and risers? Make it a full fresh water cooled engine by including the exhaust and not just the block.

Don't know about the diff. between marine and auto heads.

"You may want to do some resea

"You may want to do some research on the use of alum heads on big block engines, especially in marine applications. They tend to warp easy and will not take any overheating no matter how careful you are. When I retired, my shop had warped and cracked alum heads stacked to the rafters. I would stick to cast iron and enjoy a measure of peace of mind."

Bill has some good points... T

Bill has some good points... There are certainly durability issues.

There is also the factor of bolt holes for bolting up accessories to the heads. Make sure you've got all the right holes.

"You didn't mention the si

"You didn't mention the size of the hull.
You might windup spending a lot more money than you think you will. Just for argument's sake, let's say you get an honest fifty hp more out of the engine. You might realize 6 to 8 mph more.
Will you get the money back if and when the boat is sold? Doubtful.
The stock answer on these boat forums is, "If you're not happy with this boat, sell it and get a boat more to your liking."
Remember, this isn't a car, 50 hp is nothing to write home about."

"Just to add to what's alr

"Just to add to what's already been said, your actual speed increase will be the square root of the power increase.
In your case going from 330 to 380 hp will net you about a 7% increase in speed. So if you are able to make 50 mph now, you might hit 54 mph after the changes.
If you really want to make some waves you need to drop in something like a built-up and blown 502 making 700-800 hp. Using the same 50 mph base case that would get you about 75-80 mph.
Don't even ask about fuel consumption.

Rod"

"Currently building my 454 fro

"Currently building my 454 from a bare block... a few things:

1) stick with oval port heads, the rectangle's don't make enough torque in the RPM's a boat needs.
2) stock cast short blocks should not turn much over 5K.
3) Sticking with number 2, a high performance ignition is not required.
4) I would stick with cast iron heads. If you are increasing the compression, that's different - but your bottom end is staying the same. World, Dart and others will all outflow the peanut ports as well as the 781's, 049's etc... GM l29 heads are a decent upgrade if you can find them cheap.

Intake, heads, cam, exhaust should easily net you the 50HP, but at a steep price if all of those things are not needed.

An option for cheap exhaust is to use the 496 MAG exhaust and risers - they are a significant improvement over the 'ol 454 330...and you can find them fairly cheap if a HP seeking nut just took them off to upgrade to a multi thousand $$ exhaust.

I considered the Edelbrock marine heads, but over the last year I have been working on this - they seem to be getting removed from various suppliers web sites. Not sure if it's lack of sales or what - and don't hold me to any of this."

Why would you rebuild a 454 wi

Why would you rebuild a 454 with only 175 hours on it. I'll trade you for mine it has 1105 hours and runs like new. Since you wnt to rebuild. Might as well rebuild mine and ive me yours

How is the old outdrive gonna

How is the old outdrive gonna like this sudden increase in power? If it's running good leave it alone.Like everyone says 50 hp isn't worth talking about on the water.