Well my 5.0 in my Formula doesn't need replacing just yet but I just blew up the 5.7 that was in my boat so I'm going to stuff a SBC 400 into it that I had layin around for emergencies.. Weight is a big factor in boats, so I was wondering if a set of alum heads off of a '95 lt-1 would fit?? Any thoughts? I would need an intake to use a carb for these heads.. This mission is strickly torque from idle to max 4600-4800 RPMs..Help! Thanx! BOB

 

The late model LT-x heads are reverse cooling. You would have to do a bit of work to get them to be right. To some, it's not that bad, to others, the ends don't justify the means.

Also, 400's like to breathe...a lot. They are a big motor. Keep that in mind.

What cam is in the engine? Or at least, what cam are you planning?

Any SBC intake (gen I) will work. Both Holley and Edelbrock make good marine carburetors.

On a side note....you have a 400 block sitting around...for an "emergency?"

::funny look::

Why wasn't it "emergency time" a while ago for your car?

 

The engine that's in the Formula works precisely from idle to redline so I couldn't justify retiring it..I learned something about the unpredictability of performance upgrades from my two ex-wives.
Boat engines have to have real grunt in the low and mid ranges, waiting for big heads and big cams to turn on at 4000 rpm is not a sensible option..
An aluminum head with small valves and 160cc runners would be ideal for torque-something like the 906 vortex, only alum.. The cam is mild RV..
As far as having a 400SBC laying around.. I sleep better knowing that I don't have to hunt for one when the time comes..Time better spent hunting for wife #3.. Thanx!

 

Weight is not that big an issue when it comes to boats.
The 40 lbs difference between a pair of aluminum heads compared to cast iron is not an issue to a boats performance. Over durability is a big boat issue. Get a performance cast iron head for your boat. The drag caused by a bad hull design has much, much more efffect on boat perfiormance.
A 400 will have a bunch more low/ mid range torque and easily get your boat "up on plane", if your old 350 could.
If you drasticly increase the power output of your boat you'll likely want to re-prop it.

 

This short block has the deep dish 8.5 pistons in it so I'm going to try and get a set of 64 cc Vortecs to bang up the compression almost a point and the newer chamber design should help overcome the poor combustion qualities of the original 882 heads that were on it with 76 cc chambers.. Thanx! Any thoughts?? BOB

 

A good choice for a upgrade from 882's on a boat. Mercury marine uses vortec heads on many of the gen 1+ small blocks they use like the 5.7 litre black scorpion ski boat motor. You'll really like the power increase over the 882's. two thumbs up....

 

I obviously didn't read the original post carefully enough.

You know the rules, boys...