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Ordering Parts for our 454 stroker Any Suggestions???

S

swampdonkey

Well-known member
We are ready to order parts for our 496 which we will be installing on a 18 foot Panther with 2:1 gear box. I would really appreciate your input before we order these part and get some feed back on weather we are on the right track. We're estimating to produce approx. 600 HP with this assembly. Also should have board range of power thoughout. I understand that airboat engine requirements are severe but how severe that is the question. Thats why I'm looking for some feed back.

First question? Cast crank or forged steel?
I can get a Cast Eagle 496 crank with I beam rods rated for 700 HP. Will this be sufficient or should I upgrade to forged steel 4340 assembly?

Second question? Hyperutectic Pistons??? or Forged????
Also my engine guy asked me"""""" to ask you"""""" what ring gap you would recommend.

Last Question for now. These are the specs for the Heads we planned on using. What do you think?
BRODIX aluminun heads RR BB-O
INTAKE PORT 270CC
CHAMBER VOLUME 119CC
VALVE SIZE INTAKE 2.250 EXHAUST 1.880
FLOW RATING IS 344 on the intake and 236 on exhaust.
For anyone that might have a Brodix catalog order # 2061001.
Once we determine the heads we are going with then I will be asking for your input on Cam Grinds. So feel free to suggest cam info.
FYI We have not ordered any parts yet!!! Before We Do
Would you change anything? I hope you can help me build my DREAM ENGINE.
I know I have posed several questions here but REALLY want to do this thing RIGHT
MANY THANKS
SWAMPDONKEY
 
Cast crank will be fine, hypereutectic will be fine.

Try to keep your RPM low. Shoot for 5200 max rather than 6000. Many people will tell you that you would be better with a lower gear box ratio (2.38 or 2.68 etc) so that you can turn a bigger prop slower (not the engine faster). It is something to think about as it will greatly quiet your boat down. Just don't get caught up in the mindset taht you have to turn your prop 3000 with a redution unit. Even a 2:1 should allow you to turn a fairly big prop with a 496, and your engine will be happier at lower RPM

I would follow the reccomendation of the piston and ring MFG. They usually have different specs for different usage''

I don't know enough about big blocks to comment too much about your heads except that you will probably want around 11:1 compression and it is better to do this with as little dome on the piston aspossible since domes can interfere with the flame travel.

Here is a good calculator that will help you later with your cam choice as well
http://kb-silvolite.com/calc.php?action=comp

I don't know if they make a head in your size range with 100cc chambers but I would think that would be a better starting point. Maybe you can look into having the 119's angle milled to reduce the volume.

Yes you can use domes and that is the easier way around....but if you want the best performance, small chamber is the way to go. It will allow fastest flame travel, need less ignition advance and have less surface area inside the chamber for less heat loss. This is assuming port design is not sacrificed, but if you can have both, it will be bad to the bone!
 
Cold, I was thinking of the Edelbrocks but IDK enough about it to recommend any particular head in this case

If I were building a 496 (which I may in the future, I do have a block) I think I would get the Edelbrocks too though

Too bad Felber isn't here to make a suggestion....
 
RD
We were thinking of keeping Max RPM at 4800 and hoping to be able to cruise at around 2500. That's why we what an engine with lots of grunt so we don't have to bring RPM up to high.
As far as the gear box we have 2:1 now but if we have to change it will be 2.68:1.
When it come time to select a prop I hope to find one that will be suitable for 2.68:1 upgrade in the future. I'm thinking four blade Sensenich but haven't done any research yet.
Hoping to run Regular gas in this baby. What do you think?
Which Edelbrock heads where you thinking of on that link? Was it the 110cc?

Thnaks
SD
 
They make a 100cc head that would give you 11:1 with flattop pistons, but again, I don't know if that will support the power level you want or not. If you are limiting to 4800 RPM I bet it would work but I would call Edelbrock and ask

You would most likely need to run 93 octane

I would go for the more compression as the 93 octane is not that much more expensive than 87 comprared to the performance you will gain. To run 87 I think you would want around 9.5:1 or less
 
Go with the RHS BBC head it's about the badest conventional BBC head out there! They use to be Pro Action until Com Cam's bought them out! I would run 11:1 on 93 and keep the quench as tight as possible you can run the tightest quench possible when you use a KB Hyper piston.
 
Waterthunder":2pnwkhab said:
Go with the RHS BBC head it's about the badest conventional BBC head out there! They use to be Pro Action until Com Cam's bought them out! I would run 11:1 on 93 and keep the quench as tight as possible you can run the tightest quench possible when you use a KB Hyper piston.
Click to expand...

WT
You didn't mention anything about the Cast Crank so I presume cast would be OK?
And when you say tight quench would that be in the 10/1000 range?

Well if we have to run 93 octane we'll have to keep some octane boost on hand for those times when we can't get premium gas.

SD
 
Thunder, you gotta admit that's a good question. Sometimes the only gas you can get is startin to get a little wormy .....
I've been in marinas where the stuff they were sellin even smelled bad.

olf
 
Theres a lot of info on the net about using toluene to boost octane. While that won't fix "bad" gas, it will give you more octane boost than the off-the-shelf brands of octane booster that don't do that much

Tight quench would be in the .030 to .040" range, and it works. I set mine at .037" and so far it is working great. Thunder's right the KB's don't expand much when they get hot so you can tighten your clearance and not worry about the pistons hitting the heads. Good rods help this too, and I think the Eagles are pretty strong stuff. Tight quench helps make combustion more uniform for more power and less chance of detonation.

Cast cranks are very strong and they are good at absorbing vibrations and lasting a long time. That's why they are used in OEM stuff. 4800 RPM is a very safe limit for the Eagle stuff.
 
My opinion if it's a 4 bolt block you can run a cast crank but if it's a two bolt I would run the 4340 crank. To be honest the 4340 ain't that much more I would go with the cheaper KB cast piston and spend the money you saved on a good crank. I don't like adding a 1/4 of stroke and use a cast crank to do it! Go with full floating pin's and bushed rod's. But most of all put the sever duty valves in it! The RHS head is a beast and their components if you buy them assembled are better quality then most assembled heads use. I would think a 1/4 arm with a good hydraulic roller with aggressive rockers and RHS head could make 700 easy on pump gas! The boat has a 496 in it and she is strong!
 
It also has the same set of heads but with a solid roller! It has ran flawless since it went in the boat and trust me the guy who own's is is a animal but he's fun to watch!
IMG_1106.JPG
 
I've never professed to be an engine builder, but one thing I kinda picked up on early was that you can't build a house without a good foundation.

If I was wondering where to spend MY money on a new motor, the crank and rods would be the first place.

K.
 
There you go. It doesn't matter what kind of horsepower your new engine will make ........ if the crank and rods can't take it then sooner or later you're going to be back to hauling scrap iron.

K.
 
Thunder, you ever see one of the cast Eagle cranks break under 6000 rpm?
 
I would rather sacrifice a few ponies for some reliability. If we get 600 HP I will be quit satisfied with that. If someone gave me the option between a 500 HP engine that I could beat on all day and could not kill it, verses a 600 hp engine that I will have reliability issues. I would pick the 500 hp. Currently running a 455 DD on a 18x8 air gator with a 72" Super Snapper. And I have to say that I'm amazed what this boat will do. Granted we don't have anything to compare to because its the only airboat in the area. Now with this new Boat even if we only get 500 HP, then add a gear box on top of that even though it is only a 2:1. Its going to be three times the boat.
The reason Reliability is our main issue, in the event of a break down only way out is by CHOPPER. Thats the only problem with these airboats only thing that can come to your rescue is another airboat. I'd love to have a real beast, but reliability is most important.

Thanks
SD
 
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