A very reputable engine designer has recommended 605 c.i. with 9:1 compression, 4.625 B. x 4.5 S. normally aspirated with tunnel ram and 2 custom 850 carbs. Build specs are Dart tall deck block, Callies crank, Crower billet rods, CP blower pistons ceramic coated, Hellfire rings, Clevite coated bearings, AFR 357 hard anodized heads with Jesel shaft system, inconnel valves, Isky tool room springs, custom cam with .741 lift. This should 800hp @6000 rpm, 734 @4600. The idea is to build a platform that blowers could be added to later. My goal is reliability and good docking manners. Anyone got anything like this?

On Isky springs...

http://www.offshoreonly.com/forums/s...1&postcount=19

I had a 632" motor built in 2000 that was very similar to what you are thinking about. It was 10.5:1 4.60" X 4.75" stroke, Heavily worked Dart 360 heads, Dart tunnel ram, 2 X 775 Demon carbs, 272/278 @.050 ~.770" on 114 (first cam) grew to 280/288 @.050 ~.785" on 115. Motor made 900hp on pump gas at 6600 and was a beast. (also a lifter breaker) A good friend of mine has a 598" built about 4 yrs ago, 10:1 4.60 X 4.50" Dart 355 CNC heads, Dart tunnel ram, 2 X1050 Dominators, ~264/[email protected] .730" lift on 114 7/4 swap that has been almost bullet proof...(both motors had/have JE flat tops in them) Here is what we learned and I would suggest and you are well on the right track with the parts, etc you listed. Valvetrain will be your biggest issue as a 600" NA motor needs a lot of cam to make the kind of power you are looking for. Isky makes a solid roller lifter called an EZ wheel.. it has roller bearings, not needle bearings....Run them. Also, try to keep lift @.730" or below and be sure the cam has "soft ramps" (IE slower valve opening/closing speeds) Don't know the spring he is thinking, but you only need about 250# on the seat and roughly 700# opening...don't get into the ~330#/ 1000# triple springs either....I personally would not bore a brand new block to 4.625" in case you need to bore it again later...if you want to go above 598" initially then go to a 4.75" stroke, just my opinion. Should be a reliable combo for you with reasonable docking manners...I'd suggest staying in the 114-115 area on LSA to help with the idle vs say a 112.
For fun...see what your builder thinks of the new 18 degree Dart 370 oval port heads...I hear they make stupid power...only problem is you'll have to go to a sheet metal intake.
You putting these in your DCB?

Yes the motors will go into the DCB. Valve train durability is the issue I have been concerned about. The designer feels this set up with Morel Hydraulic rollers should last 250 hours. I think I may be willing to give up some HP for more lifespan. But I really want to make 800hp. How often would valves need to be checked/adjusted with the solid roller cam? How much are the valve spring oiler systems? The other issue I'm concerned about is the two carbs, I was really just wanting to deal with one. The tunnel ram would look good though. I'm excited about the project but I have heard advice on the board of sticking with proven combinations!

I like the idea that you're using the Jesel shaftmount rocker arm system vs a stud mount....especially if you're persuing reliability. Also, I think you're going to appreciate it more by sticking with a hydraulic roller cam better as well vs a solid.

Are the 357 AFR heads CNC ported???

Sounds like a nice project...keep us posted.

CHEAP insurance. These are a good value- http://www.newcenturyperformance.com/Valve%20Covers.htm

Eickerts are expensive but a nice application- he sandwiches a mount plate between the head and the cover and ports the oil thru it.

If you go with Jesel shafts, theirs is integral to the system- maybe a $500 add-on.

Imco makes a set that allows removal without taking your exhaust loose- the lower edge is tapered. Easy to set up- you just tap from your remote filter or block adapter.

My opinion is that you are going to have to run such a large hydralic to make 800HP (and thats a stretch IMO with hydralic) that it would probably be more reliable going with a "relatively small" solid. I would be thinking ~6400ish as cats love rpm and prop speed. I used to run my valves once a season with the Jesels and they never moved after that...if you run a set of the 2 piece Keith Eickert valve covers its a breeze...A tunnel ram is an easy 40-50 free hp and once you get the carbs dialed in its no big deal...I ran Demon carbs off the shelf that were set up for a "TR" at Demon, simply changed jets and dialed in the idle in the boat...otherwise flawless. Can probably expect 125hrs+ from solid set up and you DO NOT need spring oilers. Get with rmbuilder...Bob Madera to discuss the cam and his thoughts on solid vs hydralic.

Here's a pic of my old 632" to get you going....

I use morel hydraulic rollers in my 582 motors making 800hp 5900 rpm,one thing that the big cube motors like is a set of big tubes,2.125 id or 2.25 id inner tube diameter,they sre expensive but engines really like them,pull out the heat and make power,the mechanical roller makes more power but reliabilty is at stake,motor makes no power when broken.It will be great when they can make a bulletproof mechanical roller set up,a lot of people trying different set ups now,only time will tell

I already have a 600 cu in package that will make 850 - 900 HP N/A on pump gas. Please feel free to contact me, there is no need to try an reinvent the wheel.

What do you think of the Isky EZ Wheel lifters? I've heard a lot of good things about them...