353 Speeds
 

Lots of threads on here about the speeds people are getting out of 382's but I haven't seen one about the 353.

A lot of people have remarked that the 353 is a little bit sportier to drive. I am curious how fast they are. Specifically with 525's, but any engines would be helpful, and interesting to others I'm sure.

A friend bought one a few years ago with 502's.....was told 72 but said he never saw more than 69. Another local one with 496HO's claimed 72 and a one time speed of about 75 if I remember correct.

GPS speeds,496ho,75-76,525's/no boxes, 80-81,525's/Stellings boxes,86-88,600's/Stellings boxes.93-94,varies of course,+/- a couple mph.

I had a friend that had a 2001 with HOs. Ran 71 to 72, fresh water lake 660 feet above sea level.

I have a 2005 353 with 496 HO's and reached 75.4 on GPS
1/4 tank and two people.

As everyone, would love to go faster but need the green to make it happend:mad:

About as good as it get right there!!

Dave

A guy running at the Sacandaga Poker run apparently teeters with the 100 MPH mark with "opened up" 600sci's. That was one fast Formula.

Aboutme3, In that pic it looks like you were running from some nasty weather! Is that when you got your top speed?

The conditions in the pic, is that about how rough your boat likes it to run its best? Looks like 2-3's

Not sure what opened up 600 SCIs means - but that speedo is on severe drugs. No way a 353 is running 3 digits, or anything close to it on stock 600s.

With stock 600's you'll see low 90's.

Our last 2 stock 600's a few years ago.93.4 and 94.8. Formula's European dealer(pokerrunboats on OSO) is at 100 mph with his own 600 tweaking,and apparently has more as he gets it dialed in. Thread here somewhere.

Macjazzy

That photo was my from my friends 292 during the 2008 River Shiver on Fox Lake. Weather looked worse than it was that day.

It was the last run of the year so pushed the sticks to the wall. (Seems like there could be a few more MPH with a different prop.) I don’t really like doing that but once in a while…

The waves in the photo are from the other boats during the Shiver. And yes, the 2 foot waves are best as it seems to release the hull and get that little extra burst of speed. The cooler weather is also a plus.

How's a 496HO (425hp?) as fast as a 500EFI (475hp?) in the same 353? Not trying to be cynical, I know you're the man MF, just puzzled.

Don't quite understand your question,never stated 500efi speeds,which generally,back in their day,were 78-80. Basically,the 496HO's are much stronger than anyone realized,and an undiscovered bargain. If you ever get a chance to run one,you will be impressed. I never thought they would run that well,but they do,and it surprised me.

Magicfloat has regularly posted GPS pics of boats in the past....although something about that Alabama water does seem faster than what the rest of us see. Roberts numbers are also new boats before they are loaded with all the crap we tend to carry around with us....that alone may explain the 1-3 mph higher numbers Robert regularly sees.

I had Merc tech on my boat updating Axius software last week. He told me that he has dyno'd several HOs - and they all come in pretty much 440 to 450 HP. I agree they are a great deal for the price.

Sorry Robert,
I was vague. My boat with 500s does 75 and change wich was what you were saying a 496HO will do. I understand elev, water, temp, and weight all play a roll with speed. I guess I'm just surprised that a 496HO will do an honest 75-76.:ernaehrung004: I'd love to get 80 with my boat... maybe she's a little tired (480 hours). Redoing the springs this winter, maybe that'll help.

No apology needed.If you had told me 3-4 years ago that a 496 HO 353 would run 75+ i would have said you're nuts. The performance of that package surprised me as much as it did you.:drink:

Sleek1,

480 hours? Is this the first time the springs will be changed?

Yes, the engines still have the factory seals on them (according to the surveyor). I bought the boat last March and wasn't about to sit on the shoreline another summer. Decided to take an "educated" risk and use the boat til this winter. The boat looked like it had been well taken care of (good brand of oil, etc) compression was no lower than 153 and most were in the 160s. Not many hours at WOT. No problems so far and I'll get the springs done before it warms up again. Oh wait, it was 87* yesterday.

Pretty sure they don't seal the valve covers on the 500's or the 525's. That's all that would need to be removed to replace the springs. Not only that, I would think at that, 480 hours, they would have had to be replaced WOT alot or not.

Just my .02!

Dave

Yeah, maybe you're right. All I know is I bought the boat from an OSO member whom I trust. He said the springs were never done and he was about to do them when he decided to sell the boat. The surveyor (very well respected member of OSO) told me the engines were never opened "they still have the seals on them". I'm no mechanic so I took his word on it. I don't see what advantage it would be to tell me the springs were never replaced if in fact they were. Either way that's what I "know" and am thankful I didn't have any problems.

Sleek,

The wire seals are on the heads and the intake manifold. If the guy who sold it to you said they weren't replaced, I'd believe him. From the info I've gathered the 500efis have a lot more longevity in that respect as compared to the carb'd 500s. My buddy Axa is a bit of a valve spring afficianado. :D His little buddy and him discussed this topic in the boathouse at length :angry-smiley-038:

Not to be argumentative here, but Merc places the seals thru two of the intake bolts and thru all three of the balancer bolts. That is the way my carb 500s were done, that's the way my 525s are done. I can only believe the in-between 500 EFIs were the same. Never seen the head bolts done, or the valve covers. Merc has a service bulletin on the 500Carb/EFI to "check" valve springs at 250 +/- hrs. I do have a close buddy that has 400+ on the springs in a pair of 500 carbs and it still runs fine, he does not run it very hard at all. He even went 300+ hrs before he broke down and put a set of plugs in it.

As far as springs go...............500 carbs had Crane which were chit. 500 EFIs have Comp springs which are marginally better. The springs to use are Isky SP Endurance or the Isky Tool Room springs, more money for sure but then you get what you pay for. I believe the other half of the Boathouse debate went with Iskys in the last round of rebuilds.

I love it when you guys start talking about valve springs!!

To do the springs or not to do???:drink:

No problem fellas, I'm not trying to start another debate on valve springs. I was just telling my story and the fact that I'm replacing my springs this winter at said hours. I'm only posting this info because there seem to be at least two camps between the 500hp and 500efi as to when to replace springs. Take it with a grain of salt... it's free info and we all know you get what you pay for.:drink: I guess we did get a little off topic, didn't mean to be a thread jacker.

How many hours are you at?

290!!! :drink: and you?? I was thinking you were going to pass me on the water and on the HR meter this year..:rolleyes:

I see a challenge starting up here. Who can go the most hours on old spent valve springs before one breaks, drops a valve, and takes out a piston.

Bob... :argue: ...Mike

what is the cost of a good set of springs for the 500 efi's installed?

I've been quoted 3k-3.5k. Milled heads, new springs comp or isky, felpro gasket, and labor.

We have a customer here in central California who has a 353 with the Raylar 103-525HP kits and CMI headers that I know has clocked consistant mid 80's at 5100 rpms. I believe his boat is for sale now with low hour and great equipment for anyone who's looking for this model and power its a great boat! Just thought I would chime in about 496's in 353's.

Best Regards,
Ray @ Raylar

I just think Bob and I bought better engineered equipment to start with. I'm at 132. By your way of thinking , you should be about ready to crack the 525s open this winter for new springs. '06 with no seals on the motors, sweet.

I like the way you think. Run'em that's what they're made for!:ernaehrung004:

I better call Dave!!!!:drink:Fast!!!

No intention of doing that, only at 100 hrs now and the 525s are supposed to go close to forever. :D But If I own it at a couple hundred I might consider a spring change then. These are sealed same as any of the others, I've just never seen any with the heads or valve covers done.

I just think that it is money well spent to maintain the valve train, and 250 hours seems to be the number Merc is stuck on. My 500s didn't make it that far so maybe I'm overly cautious of this. It's a crap shoot at best, but the more hours you run the less of a crap shoot it becomes.

I'd have to be smokin' crack to dick with these 525s. :cool-smiley-027:

Can you say super charger??? 100 mark would be something we could talk about:drink:

fastech 353 speeds
 

2006 600sc merc. maximus 32 props 86.8 MPH GPS two people half fuel. Tried a pair of Herrings same speed but smoother and less mid range porpose.

I could say Whipppppppppppppple Chargers! Or just stick with a pair of 525s in the newer staggered 35 and easily top the century mark as well. The world is full of possibilities! :cool: