Which big block - 454 or 496?

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DJM2203
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Which big block - 454 or 496?

Post by DJM2203 » Mon Aug 01, 2016 8:33 pm

Thinking about changing from 454 to 496. Would it be worth it ?
Doug Massey, Big Block 468, 3 bladed R, Gearbox 237, Davie, FL

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Re: Which big block - 454 or 496?

Post by happy harold » Tue Aug 02, 2016 7:55 am

if you're riding free, keep you present set up. any upgrade is costly and time consuming. if you need more power to run the bad rough, or just want to be number one, go for it.

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Re: Which big block - 454 or 496?

Post by jeepinocala1111 » Tue Aug 02, 2016 9:55 am

DJM2203 wrote:Thinking about changing from 454 to 496. Would it be worth it ?
Is there a weight difference?

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406 JAMIE
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Re: Which big block - 454 or 496?

Post by 406 JAMIE » Tue Aug 02, 2016 9:58 am

hello and maybe think about keeping ur 468ci motor now but throw a different custom ground cam shaft from BULLET for ur set up on ur boat to wake it up if thats what u r looking for.if u have any questions plz feel free to cal RANK HIGH PERFORMANCE 321-727-1564 ask for Michael lil brother will help u. And we r setting up a flywheel Dyno wright now as we speak.hope this helps y all besafe :rebel:
Last edited by 406 JAMIE on Tue Aug 02, 2016 10:14 am, edited 1 time in total.
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SWAMPHUNTER45
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Re: Which big block - 454 or 496?

Post by SWAMPHUNTER45 » Tue Aug 02, 2016 10:04 am

A lot depends on the current engine your running as far as how much you will gain.

The 496 platform will safely yield 600 foot pounds of torque in the 4500rpm range if built using good heads and a moderate cam on pump gas. Should you be running a build similar to the GM 454HO crate engine now and switch to a quality 496 roller build it would be a very noticeable increase in torque and power. That said you can't just slap a crank kit assembly in and expect gains, a stroker needs better head flow, big valves and a well thought out cam selection to breath and bring power in at the right rpm.

It would be a cool build

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Re: Which big block - 454 or 496?

Post by Joe » Tue Aug 02, 2016 12:51 pm

Agree with most of what was said. But,are you talking about a stoked 454 to a 496 or the 8.1 gm 496? There very differant engines and in my opinion the 8.1 is a waist of money and time. There's not much aftermarket stuff out there for them.
But if you stroke a 454 with good heads,forged pistons a good cam,that's not always easy,and the right head set up it could be a bad mofo!!
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Re: Which big block - 454 or 496?

Post by akblackdawg » Tue Aug 02, 2016 1:08 pm

Weight is basicly the same, 496 stroker uses the same block, just bored out a bit more and stroked. If you go to search, Crowhater posted several years ago a parts list and build instructions for a very simple 496 with all new parts, etc that was a tried and proven set up for airboat, might do a search for that build and compare. Bud
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406 JAMIE
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Re: Which big block - 454 or 496?

Post by 406 JAMIE » Tue Aug 02, 2016 2:06 pm

Michael at RANK HIGH PERFORMANCE did a 414ci bbc for me have video of breakin and we got 475-485 hp and wright around 440-450 lbs trq on 87octane as dave says 7-11 best regular 87.made a hugh difference from 350ci/330hp sbc to that bbc i ll take the weight over the trq at low rpm.so ur 468 is a great combo custom ground cam shaft and some head work would really wake the 468 up.jmo hope i can help y all besafe :rebel: :rebel:
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Re: Which big block - 454 or 496?

Post by Waterthunder » Wed Aug 03, 2016 10:21 am

Thats Cool Jamie,, what Dyno did you all get we have a 1,600hp twin rotor Stuska with DEPAC system. I have heard two other people in town are getting one too.
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Re: Which big block - 454 or 496?

Post by SWAMPHUNTER45 » Wed Aug 03, 2016 10:31 am

Can you do a Cadillac on yours Dave ?

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Re: Which big block - 454 or 496?

Post by 406 JAMIE » Wed Aug 03, 2016 12:26 pm

SUPERFLOW dyno and swamphunter we can for u just give Michael a call321-727-1564.and yes we r talking of doing aircraft engines too. :rebel:
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Re: Which big block - 454 or 496?

Post by Debo75 » Wed Aug 03, 2016 2:12 pm

How pitched are your R blades? I went from a 454HO to a GTO/MAS 509c.i. and now I have a "good problem"..... I'm at the limit of my prop. I'm looking at several thousand dollars for four new blades haha. So something to keep in mind.

We need more info... Is your 454 already bored to a 468, like your signature line says? Aluminum heads? What kind of horsepower do you think you're currently making? And what are the specs on the 496 you're looking at?
20'x8' GTO w/ MAS 509 BBC, 2.38:1 Stinger, 4 blade Power Plus.

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Re: Which big block - 454 or 496?

Post by DJM2203 » Wed Aug 03, 2016 4:46 pm

I've got a 454 bored out to a 468; aluminum brodix heads, comp cam; I'm turning the R-blades at 2.5 5100 RPM. Thanks for your help and any more information ...
Doug Massey, Big Block 468, 3 bladed R, Gearbox 237, Davie, FL

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Re: Which big block - 454 or 496?

Post by Waterthunder » Wed Aug 03, 2016 4:52 pm

Years ago we thought of doing AC motors but the heat they put of will require about twice the venting/exhaust fans of a car motor. Also I personally don't believe many people will want to dyno their AC motors. Let me know how that goes for you we choose not to do it. Were doing some mods to ours. I had one of our 418s dynoed in town on a chassis dyno it was down 80HP from where It should be at the rear wheels. So we tried another dyno in town and it picked up over a 100HP same car same week zero changes. One of the chassis dynos in town is a POS. They had to have 4 people on the trunk just to try and limit wheel spin. And of coarse they said the motor was down on power instead of saying the tires were spinning. I just gave the customer his money back screw the BS and what ya know it makes over 200 HP more on a engine dyno than a chassis dyno. Not to mention over a 100 more HP by just driving 18 miles away to another chassis dyno. More the reason I put my trust in a prop you can hand somebody a dyno sheet that says what ever the builder wants. But bolt a prop on it and everyone knows the truth. Lately many dyno numbers are less believable than what Hilary Clinton says.
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Re: Which big block - 454 or 496?

Post by goldhunter_2 » Wed Aug 03, 2016 8:01 pm

Waterthunder wrote:Years ago we thought of doing AC motors but the heat they put of will require about twice the venting/exhaust fans of a car motor. Also I personally don't believe many people will want to dyno their AC motors. Let me know how that goes for you we choose not to do it. Were doing some mods to ours. I had one of our 418s dynoed in town on a chassis dyno it was down 80HP from where It should be at the rear wheels. So we tried another dyno in town and it picked up over a 100HP same car same week zero changes. One of the chassis dynos in town is a POS. They had to have 4 people on the trunk just to try and limit wheel spin. And of coarse they said the motor was down on power instead of saying the tires were spinning. I just gave the customer his money back screw the BS and what ya know it makes over 200 HP more on a engine dyno than a chassis dyno. Not to mention over a 100 more HP by just driving 18 miles away to another chassis dyno. More the reason I put my trust in a prop you can hand somebody a dyno sheet that says what ever the builder wants. But bolt a prop on it and everyone knows the truth. Lately many dyno numbers are less believable than what Hilary Clinton says.

ya we see the same thing on the Chassis dynos people come in say they dyno somewhere else on a no load dyno and can't understand why they don't make the same power at the wheels , we try to explain a eddy current dyno vs some of these others but it goes in one ear an out the other.

your right on the wheel slip but you/they should be able to see it on the graph. Some of these newer cars have so much exhaust piping back there it makes it hard to get the straps in a good spot to pull it down
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Re: Which big block - 454 or 496?

Post by SWAMPHUNTER45 » Wed Aug 03, 2016 9:38 pm

I was thinking of bringing the old "JohnC" engine down for a few pulls after we freshen it up. Just to see what kind of torque curve it makes with mods.

Its a few weeks away from being done.

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Re: Which big block - 454 or 496?

Post by Waterthunder » Thu Aug 04, 2016 10:15 am

Especially when you have stuff like 22'' wheels, Lock up converter, over drive,,,, some drive trains are just a power sponge. I heard this and in my opinion its the best explanation of chassis vs engine dyno. A chassis dyno is like weighing your self on a scale fully dressed and a engine dyno is weighing yourself with no close on. But you must consider everybody dresses themselves differently.
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Re: Which big block - 454 or 496?

Post by RJC5778 » Thu Aug 04, 2016 10:44 am

i have had both engines run on the same boat, i blew my 454 up (dropped and lifter) complete tear down, blue print and rebuilt to 498 stroker, only thing he used was the block and main caps, built for airboat/marine application, beat the dog out of it and runs great with good usable power, brodix heads, k1 crank, mahle pistons, comp cam, pro filer sniper intake, inconel exhaust valves, 850 quick fuel, "stupid throttle response" i have a dyno sheet on the build thread i did "robicheaux hull rebuild 496 stroker", give it a read. it has all the specs on there with cam card numbers and timing, engine was dynoed by the builder and made 592 hp at 5400 and 602 lb ft at 4700, i spin a 3 blade r at around 2 with a 1.92:1 century drive (old gen 4 unit, i think) i run dry with a 16' wood deer stand and 4 guys plus tools in the boat in the dry marsh....just dont stop hahah. anyways i can give you my engine guys number and you can talk to him, we have lots of airboats down here in south la and i have heard nothing but good things from him and he tells you like it is and gives you the best parts money can buy, i have a buddy who has 1000 + trouble free hours on the same motor except he has afr heads instead of brodix, everything else is the exact same, and he runs the crap out of it.........

http://www.southernairboat.com/phpBB3/v ... heaux+hull

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Re: Which big block - 454 or 496?

Post by Waterthunder » Thu Aug 04, 2016 2:27 pm

Combo sounds well matched only thing I would do different is Mahle pistons do have minimal skirt surface area they are a awesome piston ran over a 100 sets in airboats.. However in sever duty airboat applications I have seen several sets fail. Once you go into major detonation the Mahle pistons have issues. The problem gets worse as the bore dia is increased. However this is only a concern when people beat the shit out of their stuff it's not a issue with the average boater or anybody who treats their boat reasonably.
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Re: Which big block - 454 or 496?

Post by RJC5778 » Thu Aug 04, 2016 3:50 pm

we both treat it "normally" with the occasional flogging if needed, thanks for the advice waterthunder. i think i have some great parts in my engine, i dont hesitate to flog it when needed but its mostly cruises at around 3500-4000 most of its life

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Re: Which big block - 454 or 496?

Post by DJM2203 » Thu Aug 04, 2016 8:44 pm

Thanks for the information! Sounds like you have a great boat. Didn't want to buy a new prop; wanted to keep my 3 blade R; just don't know if it's going to be big enough. Thanks everyone!
Doug Massey, Big Block 468, 3 bladed R, Gearbox 237, Davie, FL

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Re: Which big block - 454 or 496?

Post by goldhunter_2 » Fri Aug 05, 2016 8:12 am

Waterthunder wrote:Especially when you have stuff like 22'' wheels, Lock up converter, over drive,,,, some drive trains are just a power sponge. I heard this and in my opinion its the best explanation of chassis vs engine dyno. A chassis dyno is like weighing your self on a scale fully dressed and a engine dyno is weighing yourself with no close on. But you must consider everybody dresses themselves differently.
yep everyone's car is setup is a little different but have average losses in power of what power actual makes it to the tires, the reference of clothes on vs off could be a fair reference while some ("power sponges") mite need a suit case of clothes for the compassion of loss. I consider a engine dyno as good bragging rights and break-in/test, tuning , but a Good Chassis dyno that can actual "load" the vehicle an calculate the cars weight, drive train losses, temp etc etc gives you a Real World number of what they really have on the street or pull up on the line.

You could "Unload" the car and run it on a inertia roll dyno like allot of the dynojets but why :scratch: It would get the numbers closer to the engine dynos with no weight and only drive train losses, but really guys only ask for those when they want bragging rights to their buddy's and we don't like doing those, my opinion is they should just use their engine dyno sheets for that game as it will give them the best numbers on paper. Now a useful comparison would be is a guy who takes his engine dyno sheet and compares to a loaded chassis dyno sheet to see how much drive train losses they have and if they can make improvements to reduce those losses.
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