MPH guess-ta-ments please.

[Donzigo]

I'm thinking about taking the leap and putting either the new big block Merc - H.O.s or taking the huge "I must be nuts" leap and go for 525's. As most of you know, I have a 1989 Z-33 with Bravos and 454's . I know it will be expensive; but, when did that ever have anything to do with this obsession? Anyway, just for grins, what do you think either of these upgrades would bring in cruisng speeds and top speeds?

Now
Cruise = 3,500 rpm -40 or so MPH.
WFO = 4,400 rpm - as originally designed, precisely 60 MPH

8.2 HOs
Cruise = ?
WFO = ?

525s
Cruise = ?
WFO = ?

Hey, it's not brain surgery, throw me a guess...........

[BUIZILLA]

the FWC 496 Mag's at 375 hp are unbreakable... and they seem to be underrated from the actual 390+ hp they produce... the HO's only produce about 415-420hp tops...

[Donzigo]

I've heard that over and over, 496 mags are unbreakable & under-rated.

[gcarter]

Richard, with your unstepped hull, it would probably be a case of diminishing returns after much more than 400 HP.
I think your 496 idea is excellent.

[undertaker]

the FWC 496 Mag's at 375 hp are unbreakable... and they seem to be underrated from the actual 390+ hp they produce... the HO's only produce about 415-420hp tops...


496 MAGS unbreakable and 496 HO's are........fill in the blank...just curious what you thoughts are on the HO's. wink: ..thanks..

Undertaker:)

[Dr. Dan]

496 MAGS unbreakable and 496 HO's are........fill in the blank...just curious what you thoughts are on the HO's. wink: ..thanks..
Undertaker:)

:spongebob: ......496 HO's are ......."not Blue and they are not 525's !"

Donzigo, I agree with the others... that is a heavy hull, I am sure there is an argument to go to the 525's, but I am guessing the actual real numbers would not justify the Premium for Entry into that club.... however, if you are patient and you shop around for some Blue Pull Out Engines, from another stock newer Factory Boat.... you can save thousands...on any of these options BTW! Blue 525's I have seen for as low as $32,000 for a pair, up to $38,000 or more. Pullout 496's are plentiful among the Offshore crowd ($9000 to $14,000).... just shop and be patient... Cash Is King! But it goes fast..... I can attest to that!

As for speed estimates: Plus or Minus 3 MPH for any combo below....

496 Horizons : 64 to 67mph

496 HO : 66 to 70 mph

525's : 69 to 74 mph

Good Luck!

Doc :smash:

[Donzigo]

Thanks, I had forgotten about the laws of diminishing returns on my heavy hull. Dan, very good point...............I think 496 makes the most sense. Air 22..........did you say the 496 HOs are not so good? You say I can find two take outs for 8K to 9K each?

[Barry Eller]

My $.02 says 502 Marine Crate motors. Use as much of your old hardware as you can, get out for $11K for 2 "NEW" blocks. 502's give more options than 496's, IMHO.

All of your 454 parts are interchangeable with a 502, too...

Of course, I'm pulling mine out tomorrow to rebuild...:bonk:

[undertaker]

:spongebob: ......496 HO's are ......."not Blue and they are not 525's !"
Donzigo, I agree with the others... that is a heavy hull, I am sure there is an argument to go to the 525's, but I am guessing the actual real numbers would not justify the Premium for Entry into that club.... however, if you are patient and you shop around for some Blue Pull Out Engines, from another stock newer Factory Boat.... you can save thousands...on any of these options BTW! Blue 525's I have seen for as low as $32,000 for a pair, up to $38,000 or more. Pullout 496's are plentiful among the Offshore crowd ($9000 to $14,000).... just shop and be patient... Cash Is King! But it goes fast..... I can attest to that!
As for speed estimates: Plus or Minus 3 MPH for any combo below....
496 Horizons : 64 to 67mph
496 HO : 66 to 70 mph
525's : 69 to 74 mph
Good Luck!
Doc :smash:



Stop given me a hard time and return peoples phone calls.....:) :) :) :)


Undertaker:boggled: :bonk: :propeller: :pimp:

[undertaker]

I am just curious why Buizilla thinks MAGS are unbreakable, wondering if he thinks HO's are or are not...I value his opinion.:) :) Thank You...:)


Undertaker:pimp: :shades: :hyper: :tongue: :anchor: :smash:

[undertaker]

Sorry for the hijack.....:) :bonk: :)

[smokediver]

unless you want the mercury name , i would check around and see what kind of set up you could get from an engine builder . I bought a factory merc.350 for my 16 a few years back . I ended up hydro-locking the engine , bent rod , in short , i needed a new motor ... i kept all the accy's and brackets and had a really nice 383 built and have been really happy with it ... way better internal parts than mercury put in the 350 . i can't speak for the 496 but the merc 350 wasn't anything special by a longshot ... just another option to think about ....

[BUIZILLA]

I never said anything was wrong with the ho's.... :cool:

for this specific application, and this specific owner, I think the 375's are better...

:yes:

[undertaker]

Buizilla thanks...was just curious thats all....:) :)


Donzigo IMO I would go with the 496's either MAGS or HO's great motors and money spent will be less than the 525's and you will have nice turn key performance. Speed should be close to 70 mph... I don't think the 525's will be worth the extra jing you will only gain a few mph IMO....you can always upgrade the 496's down the road if need be:yes: :yes: Good luck keep us posted..


Undertaker:pimp:

[Cuda]

Richard, is there anything wrong with the 454's? Are they mags?

[BigGrizzly]

I am going to jump in here. The 496 is not the save all. It was designed to haul heavy loads at moderate speeds. The intakes and valves are small,rods are small etc. The 502, 540, and 572 (*0would be a better choice. The only way to do the 496s in your boat and go would be s charge them. The other thing is the 502* stuff is bolt in! There is NO substitute for Cids. If a 496 does this and that and a 502 does this and that the 502* winds. In the long run the 502* will work better in fuel economy and speed. A blue motor is not necessary. Why do you think there are so many 496 take outs? Besides For $9000->15000 each invested in what you have what would that go. A rebuild and S.charger 575 to 600 dependable Hp? Now we have a big pot of options to stir around. How about 2 540cid with 700 hp that runs on 87 octain for $23000 each. Saw this the other day, makes me wonder.

[Cuda]

I doubt it will run 70, even with HO engines. My Formula is heavy as a Tiger Tank, and it runs 78 with about 500 horses per side, with surface drives. I doubt even 525's would get you a whole lot over 70.

[tigweld]

Will you ever be satisfied????? Get the 525's or you will wish you did later:bonk:

This is from experince:lookaroun: .

[Mr X]

I doubt it will run 70, even with HO engines. My Formula is heavy as a Tiger Tank, and it runs 78 with about 500 horses per side, with surface drives. I doubt even 525's would get you a whole lot over 70.
I agree 100%, why not get rid of the old girl and buy a lighter, modern, stepped bottom hull, made of state of the art materials?? ..... :wink:

[undertaker]

Ok, look, we already know your going to be buried in that boat.. So go for the gold, get the 525's.. even if it doesnt do 9billion MPH, the coolness factor every time you open the hatch (and you will open it a LOT! ) of the four CMI headers sitting under there is way off the scale...


True....:yes: :yes: