"build" me a 500hp LSX that runs on 87

[OffshoreDrilling]

I am toying with the idea of building a motor for my boat. It is definitely more of a "what would i build if i could?" idea than anything right now. My 496 mag has really low hours and is worth around $8k with all the accessories still hanging off of it. At that price, i could probably build a motor and have it be a wash or close to it.

500hp is the most i'll be able to get away with while hopefully keeping my drive happy. Upgrading to a more stout drive is big bucks. The torque difference of a BBC vs SBC at low RPMs should be fairly gentle on it.

-500hp crank
-must run on 87 octane
-Naturally aspirated
-gobs of low RPM torque, average power>peak
-utilize as many factory parts as possible. Keeps it cheap to repair and parts plentiful.
-RELIABILITY. This thing will run at WOT for extended periods of time. 20+ minutes

Click to read more...

 

[syP]

DO WANT

 

[OffshoreDrilling]

Personally, I am thinking something along the lines of an L92/LS3 stroker. I don't even want to fuck with a factory crank, rods, or pistons. The increased stroke will be great for torque as well. The active fuel management will help with economy as well, if i decided to stick with a GM computer.

-416/417 rotating assembly
-Factory heads/intake
-Custom cam
-Double roller timing set (can you even get one for an l92?)
-Hardened pushrods
-Upgraded valve springs
-Roller bearing upgrade on the factory rockers
-ARP head studs

I dont think that would be unreasonable to acquire for $5-6k

 

[Smokinhot]

I'll be rocking one as soon as I get my cam and tune from brandon.... Actually I'm just heads away from it, but real close

 

[Smokinhot]

*edited

or at least get my 243's ported and polished

 

[Yaj Yak]

hhhmmmm

Forgive me just cuz i don't know but how would this mount up to your outdrive?

and also- exhaust what would you do for your manifolds...?

 

[OffshoreDrilling]

the merc bellhousing bolts right up to it KJ. You can bolt a powerglide or a th400 to a BBC and an LSX. the 496 is the same 8.1 found in the late model GM trucks.

Hardin, Indmar, and ilmor all make headers or manifolds for it.

 

[OffshoreDrilling]

There is a skater 28' cat with two bone stock 5.3's in it that does over 100

 

[Yaj Yak]

That's Fucking nuts. Ps we are an ilmor and indmar dealer for when you do this

 

[Yaj Yak]

Maybe also look into what ilmor does? They are running all lsx motors in mastercraft. 5.7,6.0,6.2,7.4

 

[Yaj Yak]

the merc bellhousing bolts right up to it KJ. You can bolt a powerglide or a th400 to a BBC and an LSX. the 496 is the same 8.1 found in the late model GM trucks.

Hardin, Indmar, and ilmor all make headers or manifolds for it.

I didn't realize the 496 mounted the same as older bbcs. I know the 496 is same as 8.1.. They are in Fucking everything too

 

[Euro]

 

[OffshoreDrilling]

You were the first person i thought of when i was looking at ilmor and indmar. I know they both do engines in ski/wakeboard boats.

 

[Soulonfire11]

Now, I'm not positive, but don't you need a marine block and all that jazz? And why not be the first boat guy to use E85? Seems like the cheapest easiest way to reach your goal without worrying about accessive knock.

 

[RICH17]

Fuel economy on it wouldnt outway the cheapness of E85.

Doesnt the boat motors use different castings of the same motors but allow for bigger bearings and such since they rev for long periods of time?

 

[Lord Tin Foilhat]

Why wouldn't you spend the extra $10 on 93 and get the extra power out of it....

 

[Yaj Yak]

Now, I'm not positive, but don't you need a marine block and all that jazz? And why not be the first boat guy to use E85? Seems like the cheapest easiest way to reach your goal without worrying about accessive knock.

I would hate having to find e85 on the water. Cuz you couldn't. And there are some offshore guys running it.

 

[1quick]

I would honestly build another big block or raylar your 496, there are dudes with 500hp small blocks on alpha drives if your bravo can't take 500hp/500tq your beating the living fuck out of it, just let off the throttle when you get air and your drive shal live a long healthy life

 

[OffshoreDrilling]

Now, I'm not positive, but don't you need a marine block and all that jazz? And why not be the first boat guy to use E85? Seems like the cheapest easiest way to reach your goal without worrying about accessive knock.

No sir. It would be close cooled. Meaning the engine still uses coolant, and that is cooled by a heat exchanger using the raw (lake/river/ocean) water. With a mix of an iron block and aluminum heads, there would be horrible dielectric corrosion.

I doubt there is a pump anywhere in the world for E85 on the water. The fuel economy and range would absolutely kill it anyways. A boat gets in the neighborhood of 1-2mpg cruising. I have an 80 gallon tank, switching to E85 would be a joke.

Fuel economy on it wouldn't outway the cheapness of E85.

Doesnt the boat motors use different castings of the same motors but allow for bigger bearings and such since they rev for long periods of time?

See above, and no, same blocks utilized in either application for the most part.

Why wouldn't you spend the extra $10 on 93 and get the extra power out of it....

80 gallon tank sir. Spend $4000 on gas for a season, then add the increase of premium on top of that. Premium isn't available a lot of places on the water either.

 

[OffshoreDrilling]

I would honestly build another big block or raylar your 496, there are dudes with 500hp small blocks on alpha drives if your bravo can't take 500hp/500tq your beating the living fuck out of it, just let off the throttle when you get air and your drive shal live a long healthy life

I wouldnt build a big block for this thing unless i found a smoking deal on one. Its been done a million times, id like something off the beaten path a bit. The Raylar kit is almost $7000. I can sell my 496 in stock form and get a brand new motor out of it.

This is only dreaming anyways.

 

[1quick]

Those lsx headers are pretty big money for nice ones, but say we're dreaming here I'd go with an lsx 454 and just change the cam to a marine spec and use a fast ez- efi on it

 

[OffshoreDrilling]

I cant imagine they are any more or less than a set of performance headers for a BBC at somewhere around 2 grand.

Im dreaming up something buildable with a reasonable budget. Id build a big block if i was going that many cubes. Parts get just as expensive.

 

[1quick]

The only ls headers I could find were lightning Marine and they are 4k you can buy stock manifolds for 1500 tho but you won't put 500hp through those, budget and marine ls motor don't go hand and hand

 

[OffshoreDrilling]

Lightning Small Block Chevy LS1 Mercury Headers - KE Performance

 

[1quick]

Ah yeah these were the only ones I could find but I'm out in the garage on my phone lol, CP Performance - Small Block Chevy