How much HP? on my 454
 

Hello-
I just got a 454 and was wondering what the estimated horsepower and torque would be.
454 bored .30 over SRP pistons(212135) slightly under 10.1 compression with
Merlin rectangular iron heads 320cc intake runner (2.30 intake valves)
Comp marine .575 hydraulic flat tappet cam w/crane roller rockers
Holley single plan high-rise intake w/ 850 dp
Cmi fusion tube headers.
Stock Merc Ignition.

Thankyou

id say 450 hp and 500 torque.

450hp

They are nice pistons, I have hit 4 valves with them and still no holes. lol
That flat tappet cam is leaving a lot on the table. I'll guess around 462.3HP

Thankyou for the quick replys. Any good gains by converting to Hydraulic roller? if so around what lift
Thanks Tom

I use to run solid roller cams 252°/264° 0.669"In 0.623"Ex, with fully ported and wedged Merlin heads with those pistons. I dyno'd 590HP/564TQ. They were pretty high strung and would not recommend that.
I would put something comparable to Comp lobe 3122/3113 on a 114. The engine builder I share a shop with builds a lot of Comp cams off this page.
Also, note by no means am I an expert on cam shafts. There are more people qualified on here for that. This would be my opinion and gut feeling with your setup that I am familiar with. It would probably put you over the 500HP and increase TQ.

Others please correct me if I'm giving misleading information. :)

How do we guess hp when all we are given cam wise is lift ? Or am I missing something.

10:1 CR seems a little on the ragged edge for an iron-headed marine engine. I would be careful with camshaft selection - you may raise your dynamic compression ratio if you go with a cam that has less overlap than the current one. Sometimes bleeding off some cylinder pressure can be a life-saver. ;)

I'm running a similar set-up as the op and per the prev owner they are right at 500HP@5K rpm.. Top speed confirms that HP to be close.
93 octane only!!!

I'm no expert but with his compression and cubic inch I'd tighten the lobes a little.

Curious what afr 315cc heads and 741 cam would gain horsepower wise? With slightly under 10.1 compression

That would be a upgrade to a roller cam and aluminum cnc ported heads

550-570hp,,540ish tq

467.9 on premium gas.

imo the 315 cnc head is not the head for a 454.i believe a 305 with cnc chaimber would work great.a 741 cam would be good but for the best cam i would call bob madera at marinekinetics.a lot of things in the setup can change what cam works the best.

What would you hope to accomplish by doing this?

Not blow it up if you got a bad tank of gas.

454 is a great foundation for a set of peanut butter ports.

Being that this is a tech section that people come to for information to help them with their projects, I think it's beneficial for people to explain themselves, right or wrong, so that everyone can learn. That's why I was asking what your thought process was on why he'd want to run a tighter lobe sep. I think, by your reply, that you've got it backwards. It seems to be a common misconception on the internet that a tighter lobe sep will decrease cylinder pressure. This is wrong. It will increase cylinder pressure, shorten your power band, and move peak torque to a lower rpm. If you have a different theory, please elaborate. Everyone benefits when good technical discussions take place. I'm laying in bed with a fever, so I need a distraction. Lol

I was thinking more along the lines of trying to help a poor cylinder head out that's going to have a hard time keeping the fuel suspended in air as it travels through the port and in return keeping it out of detontion. Right or wrong? Like I said not the expert. Please enlighten me on this theory.

The best way to make use of a cylinder head that is larger then optimal, is to increase the rpm of the engine. To increase the rpm, you're going to need more duration, more duration will move the whole power curve up, a wider lobe sep will flatten the torque curve and make a broader power band. This can help in an application like this, and make it easier to prop the boat for all around performance. Also, the bigger duration cam will effect the idle, a wider lobe sep will help here too.

Alex, if the lobe separation gives you a broader torque curve then why on engines that run in a small rpm window are they using 118-121 Lsa cams? Is it to move the torque curve way up in the motor? I don't know. Always wondered why.

Well, then let me help.

Both sets of these lobes, either when widened or put closer together, will increase pressure.

Guaranteed.

http://3.bp.blogspot.com/-WgozSmW2jO...nizales++6.jpg

454 semi closed chambered oval port 10.3-1 compr,vic jr oval intake.cam 230,236 ls110,flat tappet no less,made 527hp,517tq at 2 places,4100 and 5100rpm's.water dunoed at the end of the tails.carbs were 930 or 950cfm bolands,laws or something like that.anyone that rode in my boat could not believe how had the acceration was.any time from 30mph on up .
other thing they loved was blipping the throttle on the stand,,instant rev up,very,very responsive.
I loved those engines,,simple and fast.

Are you talking Pro Stock here ?

Let me take a stab - super effecient cylinder heads,chambers and domes, very high compression, and a ton of rpm.

oh and my tq curve was almost flat.
both engines after they were done in my boat were sold off to hot rod guys,,and they loved them.

seems like the ls guys go the other way,115 down to 112 or less

Years ago I did a GM headed 496. Just over 10:1 it had a 110lsa with more duration. Baker Outlaw billet carb. Boat went 75+ in a hull that normally goes 70 with an hp500. That thing pulled like crazy when you hit it.

Yep. I've seen a few of ex-prostock motors pulled apart some were 118 some 121

I was always told bad head needs help from the camshaft (tight lsa) good head doesn't.

Is that your wife or girlfriend the wife doesn't know about?

you know what I'm talking about then.and my oval ports worked really well,got over 600hp w/ them,,but he roller cam was crazy.for back in 2001.:D

thats every mans dream girlfriend.
then again,theres a guy out there that hates her fcking guts.

To a degree. No pun intended.

With a killer head you can shorten the duration, widen the LSA, and make the same or more power than a comparable motor with yukie heads. Yes, i said yuky. There is no better example than the LS motors vs the 23* motors.

Exahsut overlap can be called the 5th cycle on a 4 cycle engine. With limited induction and/or limited heads (basically same thing) that 5th cycle can be super important and thus why you'll see 102 or 104LSA cams installed advanced to say 98ICL or even 96 ICL.

Remember, dome interfering in the combustion chamber can effect this also....as the dome reaching into the heads combustion chamber for most all of the overlap period. Dome shape is very important for high performance motors and has come a long way in the last dozen years. Obviously combustion chambers too, as they work together.

Shhhh, secret. if it was, I would have died a long time ago......from over exertion but altleast extremely happy.

Back to peanut butter for a 454, I always wanted to see how a set of these would work out:

Brodix BBC-1 Raised Oval Ports (ported by HVH / cast by Brodix)

Intake runner: 305cc
Exhaust Runner: 120cc
2.250 / 1.88 valves

Lift // Int flow // Ex flow

.200" // 164 // 133
.300" // 245 // 182
.400" // 298 // 215
.500" // 349 // 244
.600" // 377 // 267
.700" // 390 // 280

those do look interesting.

Just had a conversation about these on a 509 went 715hp

Want intake fits on these ?

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Every time I get my spacers in (HVH cnc's them for me) they leave stickers, pens, and various cylinder head info that goes thru their doors.....these raised oval ports always get my attention. No price mentioned so i hate to ask, as most heads from there are huge $$$.

I don't know what intake it was a generalized conversation about how great Brodix heads are and how much power the make. I was told intake and heads were 5g's