Is this believable HP out of a 572?
 

I read this on a site somewhere it could of even been on here:

"these 572's so far they make 780hp @5900 & 786ft pounds torque @4700 super flow #'s ....dart pro ones 336cnc heads,dart intake, big m block ,top dollar rotating assbly, and a .612, .612 valve lift with 256in & 258ex @.050 on a 114 CL hyd roller."

The reason I ask is Im in the middle of a 582 build and expecting 725hp with brodix bb-3 cnc'd 365 runners, flat top pistons, the cam will be .258int & 262 ex @.050 with .612 lift on both and 114 sep.
Where Im at is 1400ft elevation and around 70-80f temps on an average boating day.

Could be legit, could be a generous dyno. If its on the internet you never know.

Great point! The original question posed reminds me of a YouTube vid I saw about a ZZ502 GMPP crate motor that was "built-up" and installed in a vehicle. The owner claims to have made a 700HP ZZ502. Given my experience so far with that motor, that is a very tall claim (without forced induction). When question about his HP claim and where is the dyno information, he quickly :7160:

My reaction to this thread is, don't believe numbers unless they are backed up by realistic dyno numbers. And not some stepped on correction factor.

its all in correction factor

700 is about all you will get from that build with the proper intake and carb.We get 720+ HP (uncorrected #'s) from our 572's with custom intakes and carbs @5900 rpm's but run more lift and compression at 9.9 to 1.

Interesting...I have always wondered how NASCAR gets 800hp out of their small blocked 350s and runs them WFO for 2-3hrs.

That HP is attainable from a 572 at a slightly higher RPM but the torque is bogus. That's a BMEP of 207psi at peak torque.. Not likely with that combo.

ultra lite weight parts in the recipro, every trick coating/process you could imagine, dry sump oil system, short stroke/large bore, exotic valve train and camshafting and a very narrow , high rpm hp peak.

Simple answer. MONEY.

(smittys description too)

Uncle Dave

Spinning 8000rpms also makes a big difference.

725hp is attainable all day long with those brodix cnc heads. Believe it or not, it is possible to make power with something other than an air flow research cylinder head. Adding valve lift is great if the timing events are right. If they arent, youre wasting your time

this is a dyno video of a local guy here Mark at MER that built this motor. Its a 572. Lower compression on 89
https://www.youtube.com/watch?v=THTwkuWLpCE

there is a separate video of the numbers and AFR i believe. looks to run on the lean side though. Made over 800HP though N/A

Nothing earth shattering about those numbers at all. Be interesting to know the compression and what exhaust he has. Offshorexcursion's 572's made 800 on the dyno, 750 with his headers.

Very impressive ! Are there any dyno sheets to show these numbers and why such a change with headers?

Actually i believe it was 760hp at 6000 thru the cmi headers on offshoreexcursions 572s. And i do have copies of the dyno sheets at home.

It's interesting reading old posts.. I still think the torque is a bit high on the example engine, but after using a few sets of the Darts over the years, and dynoing a couple hundred more motors since that post, it's probably not quite as far off as I obviously thought it was back then. Bogus may have been a bit strong. lol

He has 1-7/8" stack headers which are a little on the small side for a 572 in the 800 hp range and costing some power. None the less, very good running engines.

My 572 made over 1800hp...a few pounds of boost helped the Dart 360's.:)

on pump gas?please tell us more.

my pfaffs made 750 seemed to be on par for the performance I received .. I see a lot of combos stating comparible numbers

https://www.youtube.com/watch?v=to9kXm0ZdKo :coolcowboy:

This dyno session was when we were playing with a hydraulic roller cam. I didn't like how it carried the power on the top so we put the solid roller back in. It made 1830 on 110 and that's how I ran it in the boat. It did make 1500 on pump gas but probably not safe enough to run it that way in the boat. 1350 was a safe number on pump gas.

Was it a hydraulic roller? How big of cam 260/270 @.050?

Yes, do you have a link to engine specs or details please?

I don't have a link to the engine specs but it's a 572 10.2 deck. JE custom pistons with a large dish. Dart 360 heads with Valeko porting and his wedges. Static compression of 7.2:1 using a solid roller cam ground to our specs. Intake manifold was also our design and was billet aluminum.

Yes, smaller with no magic pixie dust :lolhit:


http://www.offshoreonly.com/forums/g...ser-video.html


753hp @6000rpm & 731ft/lb @4600rpm 93 pump fuel on a DEPAC Dyno with my 1 7/8th Headers, My Carbs, and My flame arrestors setup how they are IN the boat.

Will make over 800hp with larger Dyno Headers. Our first pull with CMI style 17/8ths was 780ish, once we got the tune close we put on my tractor pipes WITH muffler inserts and initially lost 50HP over the CMI 1 7/8ths. After removing the muffler inserts and re tune we ended up at the 753hp and that's how they are in the boat. I refuse to buy new tractor pipes so we didn't play around with big tubes anymore.

572 cu/in
9.95:1 Compression
Dart Big M Blocks
Callies Magnum Cranks Dual Keyed
Carillo Rods with Carr bolts
JE Pistons
Morel Hi Rpm .903 Lifters
55MM Hyd Roller Cams
7/16th Pushrods
AFR 335 CNC heads (Precisely tuned by sizing guides for my application, valve job touched up, clearance pushrods, spring pressures, etc.)
T&D Steel Shaft Rockers (Precisely setup by Foxwell motorsports)
Spring Oilers
Piston Oilers
4 Stage Dry Sump Oil System
Oil thermostats
Oberg return line oil filters
Jessel belt drive
Victor JR. intake Ported
Prosystems 1200 Dominator Carbs
Daytona Sensors Ignition

^^^^^^^^^^nice numbers,all it takes is money,LOTS OF MONEY,lol.

Not that I'm envious....... sure..... but I wish I could write a check to have my motors pumped up like that!! I will continue to cut lawns and plow snow and save my money. Congrats

Imo, that engine was ahead of its time. A true work of art, and testament to what happens when you take a few highly talented guys, who truly understand the dynamics of engines, and the results thereof, and produced a fantastic example of an engine combination as a result. That engine went into the field, and actually ran, and ran well for 150 hours! It was not some dyno queen built for business promotion, or just a bunch of money thrown around. To make something like that come together, and STAY together, takes more than just money.

In my opinion, that engine package was one of the coolest ones on oso over the years, and doesnt get the credit it deserves . Not that Im tired of reading about the 600hp 496 strokers with afr heads, but it be nice to see something like yours be discussed again. Nice to see builds that have had personal touches, and not just something off the shelf bolted on and made to work. I think you should build a pair of them for the 43 Bill!

Thanks for all the kind words. The block, crank and heads all have over 700 hours and the engine never made less than 1200 hp even in it's earliest configuration. That was back in the days of "turbos don't work in a marine application".

As far as the 43....well we just purchased a pair of 6's that will be going on for this summer so a logical first step:). Oh ya, I have a pair of NXT's for sale if you know of anyone.