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Sorry I started some bickering, but I will say it's been a informative and knowledgeable read.

Quote:

Originally Posted by Irishtornado (Post 3380122)

Sorry I started some bickering, but I will say it's been a informative and knowledgeable read.

Absolutely and sounds like Ray@Raylar has done plenty of R & D and has dotted his I's & crossed his T's :drink:

Quote:

Originally Posted by Raylar (Post 3379902)

If one wants to take these engines to the 675-690 HP level and stay with 9.0 to 1 compression for 89-91 octane fuel, you have got to increase the cubic inches, do serious mods to the stock heads or use aftermarket expensive heads, make serious intake manifold changes and use better camshaft profiles to get there.
Our $14,600 price tag for the HP525efi to HP675efi package is a good "Dipstick" for what an engine owner will need to spend to get into these power numbers with a reliable, non-drive busting, turnkey engine package.

Best Regards,
Ray @ Raylar

So theoretically this could be done to a 500efi as well? Same cubic inches just not closed cooled.

Good point Ray. There should be a standard and no BS.
I actually watched my motor dinod and I was pleased with the result. Can't brag about 600+ HP's but with all accessories, and the same headers, with water, PS pump, etc. 581 & 580, I felt was pretty ok for a 525.

Quote:

Originally Posted by PARADOX (Post 3380283)

Mercury definately under rated that motor. Obviously so they could have the high pricetag on the 600SC.

Mine was dynoed with headers and no acc.:coolcowboy:It wasn't fully tuned either.I had a 383 dynoed fully dressed with wet exhaust several yrs. ago and still had to retune it in the boat.We finished my 502 on the boat with MEFI BURN AND A LAPTOP.The total cost was under 10k including the new exhaust and I picked up 9 mph[gps] so far.The short block is stock except it was decked,balanced,line bored,new bearings,oil pump and gapless rings.The engine only had 180 hrs when it was taken apart.I bought the Edelbrock large ovals used but never installed so I saved some cash.The boat runs well on 89 octane.Tyler Crockett advised me to add the monoblade throttle body,upgrade the fuel system and get a bigger flame arrestor so I did.Will plop it in the water in a couple weeks to see if it has more snot.:evilb:

Quote:

Originally Posted by offshoredrillin (Post 3379820)

The main thing people need to grasp with the 500 and 525 that the limiting factor to the HP of these engines is the manifold itself, like cookin did if you port match everything you may get a little more, but take off the manifold and put on a single plane and throttle body spin it to 6000 and yes you will make HP. the 500/525 intake plenums like old school TPI are designed for torque. they max out at about 5600 rpm..they make a great and reliable pkg though properly done.

My boat weighs 5000 dry weight so I wanted low end tq.That's why I chose the ovals and ramjet deal.I didn't want to spin over 5600 .I like accelleration.

Quote:

Originally Posted by PARADOX (Post 3380283)

what is the boat you are putting this motor in????

ok dynoing your motor is ok but the real test is when your motor is in the boat.:drink: i drove cookins boat when loranzoe tune it . for a boat that size that baby runs great! i was surprize how fast it got up to top speed.lot of power at midrange . 69.9 on gps 75mph on the dream meter:drink: bob made some new mod to the motor and had the prop twik. hoping to fine tune the boat next week . loranzoe did a great jop on this motor.

Quote:

Originally Posted by bajabob (Post 3381286)

what is the boat you are putting this motor in????

The motors are IN A BOAT. We took out the port motor to make sure there is no issues due to a possible header leak.
Headers leaked, but little and no motor demage. It's a good thing I drained the headers after every use. The 525's are in a 08 Avanti. The last of it's kind. :) It's up for sale, but price just went up due to the great dino result. lol

Dave, I found this 302 for sale with some 500 EFI upgrades. Looks like he has heads, cam, intake work I would suspect and dyno'd at 580 HP. The ad says $75,000 but two other places have it for quite a bit less than that. It has to be close to what you want done.

http://www.imageandmessaging.com/baja/

With all of the engine builders on this thread I have a question. I have two 1996 525sc with isky cams and msd. Sometimes when I throttle the motors hard one back fires not allot not all the time. Is it carb or timing both or something different . I've ran these motors 200hrs with no problems.

Sounds Like Its Lean, Check Your Accelerator Pump.
Could Be Old And Not Getting A Full Pump Shot.
Bill

Thanks Bill . One more question after the motors were built I took off the k&n filters put on high hat flame arrestors and took off eddy marine and put cmi. Do you think that they could need to be retuned?

Eddie Young's post on 4-18 turned out to be absolutely correct. At the time it was written he was in the process of building my engines. They are 500 EFI's . Our intentions were to just wake them up a little. Eddie woke them up alright. I do not want to give away his package. He bumped the compression slightly, he used his custom ground cams. He replaced my factory cylinder heads because mine were rusted junk. The replacment heads were not ported in any way and they are intented to be direct replacements. He did use the mono blade, and matched it to the manifold. They dynoed at 599 peak corrected horsepower with the AVG. being 534 from 3500 to 5500. The torque was the suprise to me, 652 corrected FT. LBS. with the AVG. being 625 from 3500 to 5500. The engine cracks the 600 FT LBS. mark at 3200 with 604. He was also right about tuning. My engine looked like it was hook to life support. The needed adjustments were many.

My question as I've spoken to Eddie about upgrading as well. What was your HP@5500

Peak HP was @ 5200 599, the HP @ 5500 597. Peak Torque was @ 3900 652, the torque was 570 @ 5500.

Quote:

Originally Posted by Raylar (Post 3379933)

As my hopeful helpful additional post on this subject I am going to make a request (plea) here.

Please all engine owners, builders, etc., lets make sure when you talk about, run and post dyno outcomes here on OSO that you make sure the tests are done at a minimum with the engine in the exact trim and state it will go into the boat with!
I realize that just a few of us can run the tests with wet exhaust systems like Bobl and some others.

When dyno tests are run and posted where the engine is in a stripped down accessory state, dry long tube dyno headers versus stock manifolds or shorty headers or aftermarket exhaust manifolds the engine will have in the boat the readers perception and indeed the actual engine owners realization of what he will end up with in the boat under real world conditions is usually very distorted and really MISLEADING!
Remember what most engine manufacturers like Mercury and Mercury Racing provide is engine power and torque numbers based on this acurrate type of actual engine configuration and use testing.
A level playing field in testing and reporting will provide the best to all readers and performance boaters who need accurate numbers to make their financial upgrade decisions on!
I know a call for honesty and transparency in these dyno test numbers in the marine performance industry is a stretch! ,but its about time we all got on the SAME PAGE!

For the benefit of OSO'ers who need accurate information on which to base spending time and money, would those who want to sit on OSO and *****hit, brag, boast, entertain, distort, bench race and mislead for new business with some reporting, please exit OSO and go to another Offshore or boat forum where honesty and transparency are a four letter words and not ethically supported!!!

Not in any way inferring anybody on this post has done this, just want to get everyone thinking about the ways to get accuracy and report same before sharing the results and outcomes with other OSO readers.

Best Regards,
Ray @ Raylar

I would encourage our OSO advertisers to set the example and post some data.

Took my Eddie Young 500EFI up grade kit out for it's first water test tonight. WOW, The boat flies. No problems with anything. Now it's time to go prop shopping.

Quote:

Originally Posted by brian41 (Post 3378984)

You are not pull much over 600 HP with a stock "untouched" intake.... that is both upper and lower without magic voodoo nobody else can get. I would still like to see your sheets thats with both corrected and uncorrected numbers.

Tylers manifold moves the throttle body from the front to the top, that is how the RPM's are higher and more consistent.

I upgraded to new afr 325 cnc heads which flow about 335, everything else is the same, they should be dynoed soon. I'll let ya know if they make more :)