"budget" engine build...

[Boatally Insane]

Looking in to building the engine for my new project.....

The boat is a 1979 Excalibur..."24 x 7"


I would like to make 850 hp or so for it but I'm trying to do the best I can with what I have and also trying to staywithin my budget with is almost nothing....

I have a gen IV 454 mag shortblock with a forged crank and a gen VI 454 shortblock with cast crank and rods.

I also have a a set of Carrillo 6.535 rods...

I found what I think is a pretty good deal on an M3 procharger.... $1500 for the head unit, mounting bracket, pulleys, and belt....
No intercooler but have found them pretty reasobly priced at http://frozenboost.com


Soooo, what I was thinking of building is a gen IV 468 with the GM forged crank, the Carrillo 6.535 rods and JE flat top pistons. O ring the block and pick up a cheap set of alluminum 119cc heads which should bring the compression to approx. 8.5:1 running the M3 making about 14 pounds of boost or so...

This engine will be fuel injected most likely running a megasquirt III system with a holley throttle body and multiport injection...

I'll go with a solid roller cam if needed or get a custom hydraulic roller cam built.....

What do ya'll think????


Will I be able to meet my 850 or so HP level with this setup????

ANY info appreciated.....

Also, I'm still looking in to drives... I wanted to do an Arneson setup but am worried how this hull will work with a "surface" drive....

I DID however find someone who can build a "Bravo" style drive that will hold up to this HP level so I might just go that route....



Doug

[insanity]

Sounds like an interesting build. I've got a Megasquirt kit I put together about 4 years ago that I've yet to use. It will be interesting to see how it works in a boat.

[ROGUE]

"Budget" ceases to be a workable word after around 450hp.

[PatriYacht]

Doesn't sound bad but a couple of suggestions: first don't o-ring unless you're going for 20+ lbs. of boost. Second the rod length is odd for this engine build. Standard pistons made for a 4.25 stroker will be sticking out of a zero deck block by .025. You should be able to get a set of custom Cometic gaskets to make up the difference and hold the boost. You should get close to your goal with 12-15 lbs. of boost. This will require better gas than pump premium. Good luck

[Boatally Insane]

JE does make a piston (pn 257960) for a 6.535 rod with a 4" stroke in a short deck block..

A friend of mine had them laying around out of an old tall deck Merc. race engine so the price was right... Also, according to my machine shop, the longer rod will help the engine live longer at higher rpm...

The limiting factor is DEFINATELY going to be fuel as I don't have race fuel readily available.....


Doug

[DAREDEVIL]

JE does make a piston (pn 257960) for a 6.535 rod with a 4" stroke in a short deck block..

A friend of mine had them laying around out of an old tall deck Merc. race engine so the price was right... Also, according to my machine shop, the longer rod will help the engine live longer at higher rpm...

The limiting factor is DEFINATELY going to be fuel as I don't have race fuel readily available.....


Doug

Rod ratio is ok,,,all merc supercat engine have this in them...4 inch stroke an 6.535 rod...turning @ 7600 + RPM !!!!!!!!!!
But i would go billet crank..the forged will not last long and 100% buy a real good balancer and aluminum flywheel !!!!

[Boatally Insane]

"Budget" ceases to be a workable word after around 450hp.

That's why I put it in "quotes".



Doug

[fixxxer22]

Yeah, "budget" I spent about 6k this winter on my 502 mag using the right stuff from RM Builder. I did consider it a budget build. it is now a 509 with internals chosen by Bob. anyways, he said to expect 560-570hp out of it. so... You are easily going to spend more than me to get to that 850hp mark.

The boat also looks like it might need some more things to be safe with 850hp pushing it.

just my 2c

[MILD THUNDER]

I would go to a different drive than a bravo style if you are rerigging and truly want 850HP. Also, keep in mind, these old hulls, were never intended to see real high speeds. A 850HP single in that boat is going to be ALOT of power, and could give you some real high mph. Could also give you a real scary handling ride.

Thats a real cool hull. If it were me, i'd build a nice little motor out of your current mark IV 468 using the GM steel cranks, dimple rods, 088 heads, nice roller cam, keep compression around 8.5:1 or below, and add a small blower like a 177 or 250 series. 550+HP and last you a long time. A nice budget motor that wont destroy drives. I would think 550-600HP in that hull should give you a 80mph boat.

[MILD THUNDER]

Also, I would look into a new trailer, or modifying that one before you get a hook in the hull, if there isnt one already.

[Boatally Insane]

It was only sitting on the trailer like that for the ride home, then I re-braced everthing to support it better.

As soon as I get time it's going to be turned upside down so I can blueprint the bottom and start spraying some gelcoat...

My last boat was a 21' Checkmate with a 600 hp 516" engine that ran in the mid 80's....
I'm hoping to see better than that out of this hull...




Doug

[PatriYacht]

I agree that long rods are good for the engine. Just didn't know that JE had a std. piston for this build. Just trying to help keep the price down.

[jeffswav]

Also, I would look into a new trailer, or modifying that one before you get a hook in the hull, if there isnt one already.

x2 The bunks should go all the way to the end of the boat. You should not have any hanging over. It looks like the trailor is too short for the boat.

[jeffswav]

No need to have 850HP in a boat that size. Last year I was running 70MPH with 500+ HP with a 24' boat. You may want to check your xdim, I raised mine over the winter and expect some big gains from the setup. Bravo drives are not made for that much HP, anything over 550-600HP and you are pushing it. I try to take it easy on mine out of the hole.
I use the Holley MPI kit, if you have any quesions on it let me know.

[Boatally Insane]

Yes, I know the trailer is too short..........

As explained in an earlier post, it was only on this trailer to get it home from Oklahoma as it didn't come with one.
That trailer was from my 23' Checkmate Enforcer.
The boat is now laying upside down so I can work on the bottom....


The boat originally had a TRS drive so I DO have to redo the transom..
My "X" dimension will be somewhere between 17.825" and 18.325"

There is NO WAY 500 hp will be enough for this project.. As mentioned before I had 600 hp in my Checkmate which ran in the mid 80's....
I am trying to get this hull over 100.... ....Yes I know I'm not quite "right"
My wife is the one who named my "Boatally Insane"


Doug

[DAREDEVIL]

Running this boat 100 MPH is safer then the checkmate at 80 !!!!!!
The X is probably good at 17.5 i would not go lower for speed !!!!!

[Boatally Insane]

Any idea what kind of HP I could expect out of a "purpose built" 468 with a 6-71 blower and an intercooler running 93 octane?

I may have come across a deal but don't know if it is enough.....

Thanks,


Doug

[MILD THUNDER]

Any idea what kind of HP I could expect out of a "purpose built" 468 with a 6-71 blower and an intercooler running 93 octane?

I may have come across a deal but don't know if it is enough.....

Thanks,


Doug

650-700HP should be doable with that setup. Get in touch with "biggus" on the board here. I believe he runs that setup.

[CRT]

The TRS Setup that is on the boat will Hold the Horsepower better then a standard Bravo, just my 2 cents. Then you could always upgrade to Konrad down the road. Seems to be quite a few TRS drives for sale lately, you could pick up a spare pretty cheap. I ran 675 HP through them for 100hrs. with good results. Then I went Konrad on a 12000 pound mistress.

[MILD THUNDER]

The TRS Setup that is on the boat will Hold the Horsepower better then a standard Bravo, just my 2 cents. Then you could always upgrade to Konrad down the road. Seems to be quite a few TRS drives for sale lately, you could pick up a spare pretty cheap. I ran 675 HP through them for 100 with good results. Then I went Konrad on a 12000 pound mistress.

I agree. ^^^^^^^^