Z-33 rebuild - changing power - EFI vs. carb?.. help?

[TEAMPSI]

spellHello everyone and how are you. In the second week of March I should have my boat back from the gell man, ready for power.... Already decided on changing out to Bravo XR's or Imco's etc..etc..

At this point I am stuck on the motor and need to make a decision. I ran across a good deal on a 2003 496 Mag set up... I have everything... complete drop in motor, 2003 transom, 2003 Bravo drive..etc..etc..

I have been looking around for a matching set becasue I have twins... but no dice. I will probably just sell the 496 set up and look for someone who has matching twins or maybe just build up some motors.

Here are my options as I see them:

#1 - rebuild the original 454 mag Mark 4 blocks. They will need complete rebuild, plus I only have the short blocks... no heads, nothing. Does anyone know if I can stroke this motor to 4.25 without much hassel? Carb? EFI?

#2 - Bite the bullet and look for another matching 496 Mag. This option may be the most costly... I have been looking around for a good used 496 mag, but no luck. And I don't want to spend 10K for one either.

3# - I found a set of Gen 6 HP500's (carb style) for a good price. I could probably sell my 496 Mag and pay for these motors. Here's the deal... motors are torn down and in pieces. Everything is very low hours. I would get everything from carb to oil pan. Just no manifolds or marinizing stuff. I would need water pump, etc..etc.. Otherwise, it is complete. New rings, new seals, new bearings, then I'd have two zero hour motors.

#4 - Sell my 454 short blocks... sell my 496 mag set up... and start from scratch. Find a set of gen 6 blocks.. and build whatever comes to mind (i.e. 502's 540's 577's etc..etc..) This option will also take a lot of jack... but selling my 496 stuff would make it easier.

So this brings me to my online poll. Reguardless,... I would like to know from the rest of you... if you were in my shoes doing a complete rebuild and you had the choice... would you go with carbs or injection?? Let's say that cost is the same or at least close. How reliable are carbs vs EFI?? Fuel consumption difference?? I would also like to know if you would choose aluminum heads or iron heads... pros vs cons??

Thanks in advance everyone for all of the help!

Q

[MOP]

An opinion, the EFI vs Carb thing I can't help with, though I like carbs! The head thing I researched back and forth for months before plunking the $$ down I made sure everyone I spoke with knew I would be F/W cooling the new engine. For marine iron came out the winner most all said they run hotter and heat is power. No question there were many pros for aluminum, but most all I spoke with leaned toward iron. So I went with Dart iron.

Phil

[TEAMPSI]

Hello guys and thanks for all of the responses on the poll. Looks like the head choise is about even for now... but carbs are crushing EFI. Why is that? Is it becasue carbs are more reliable then EFI?? What about gas consumption? Just wondering before I make a decision...

Thanks again for all of your help!!

Q

[MOP]

Hello guys and thanks for all of the responses on the poll. Looks like the head choise is about even for now... but carbs are crushing EFI. Why is that? Is it becasue carbs are more reliable then EFI?? What about gas consumption? Just wondering before I make a decision...

Thanks again for all of your help!!

Q

EFI has is an improvement in starting and fuel economy but more complicated, I am in a fairly large marina we have the normal carb issues like all othersbut normally after several years of good service. EFI on the other hand takes good Dio equipment and patience chasing false leads, we also have problems sooner with EFI. It has improved greatly and no doubt will get better, early on we had troubles with the myriad of electrical connections going south in our salt environment that has been cured. But various sensors seem to just die at the most inopportune times, so I lean toward carbs for reliability. Have you noticed the head issue is tilting toward iron.

Phil

[Zigouras Racing]

I agree.... go with the 496's. They are engineered for durability. Keep in mind that when you're talking about the 496, you're talking 1999 - 2005 technology, versus a Gen 3 or 4 big block, which was designed in the stone age.

Our shop built almost two dozen 496 and 496 HO motors last year, and we've never had a problem with any of them. Mercruiser also has a good record with this motor. It's a better-designed casting, and the heads have a much wider powerband than the original 454 MPI.

- Paul

[TEAMPSI]

Hello everyone... thank you so much for the help!!! Looks like carbs and iron heads is the winner!!!!

I am either going to build two motors to meet those specs...

thanks again for the help!!

P.S. I sold my other 496 sterndrive set up to a guy in Austrailia!!!! Made me a deal I could not pass up...

Q

[ChromeGorilla]

P.S. I sold my other 496 sterndrive set up to a guy in Austrailia!!!! Made me a deal I could not pass up...




Yikes!!!! What the freight on domething like that from SC to Australia?

[fasttrucker]

Using the Victor Jr. manifold with carbs....makes you free H.P. that you dont get with fuel inj./ on my 502.Had the iron heads gone over, used larger S.S. intake valves.I could have spent more $$$.But Iam around 550HP.Crane makes a nice cam.Holley double pump.Boat is fast with the stepped bottom.1998 28zx.

[Dregsz]

Woo Hoo, Scot B turned my account on, now I can post, finally.

There is a guy on OSO classifieds (Victory Marine) selling new Merc 496s for $8900 - $10K depending on the HP

I can build you a set of 725 hp carbed 572s, w Iron heads for about $12k each including a Donzi.Net discount.
New Dart Big M block
572 uses 10'2, tall deck block
SRP Pistons Forged CH Flat Top 10.3:1
Eagle 4340 Forged Steel Internal Balance Crankshaft 4.25 Stroke BBC
Eagle 4340 Forged Steel H Beam Rods with ARP L19 Rod bolts
King Alecullar Pro Race Bearings Rods and Mains
Mahle File Fit Performance Ring Set
Balanced and Assembled
Dart Pro 1 325 CC Alum Heads- Fully Ported and Flowed 118cc Chamber
(I'll figure the exact discount for Iron if your interested)
Assembled For .630 Max Lift
Stainless Valves
1.63 Valve Springs
Titanium Retainers
10 Degree Locks
ARP Headstuds
Scorpion Rocker Arms
Mr. Gasket Solicore Head Gaskets or Equivalent
Dart Single Plane Intake Manifold
Comp Cams Hydraulic Roller Camshaft
Comp Cams Hydraulic Roller Lifters
Melling High BVolume Oil Pump and Shaft
Professional Products SFI Internal Balance Damper
Hardin Pan
Pete jackson Geardrive
Aluminum Valve Covers
Dyno+Tune

or you can use this as a base line and we can build from here. I also use Callies cranks and Lunati rods, (but they cost extra)

Thanks
Evan
Biggie Motors