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Swapping out carb 454 to 496 FI what is needed

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boxsterpro

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"Our week old used 1990 Sea R

"Our week old used 1990 Sea Ray 260 OV with a 454 thru a rod out of the side of the engine. I am looking to replace the whole unit with a crate 496 420HP marine chevy engine. I saw a web site for an engine with the intake manifold, valve covers, oil pan and water pump attached. What other parts would I need to complete a FI conversion? Harness, ECU, fuel pump etc.....

Thanks in advance

My boat wants to go back in the water with out being towed by a jet ski...."
 
"With out knowing how much the

"With out knowing how much they are asking, or seeing the engine it is difficult to tell weather this is a good deal or what parts you need. It may be better to just get the complete unit from merc. Then it is just install, plug in and go boating."
 
"Why bother with EFI? Carbs ar

"Why bother with EFI? Carbs are more reliable and easier to troubleshoot offshore. The marine EFIs are pretty crude now, but as they evolve they MAY get better. Maybe. Sorta. What is that code? Crud.

IMHO"
 
The boat is going from sea lev

The boat is going from sea level to 5000 ft many times during the year and FI would compensate better for the thin air at high alt.
 
"Pete,

With the exception o

"Pete,

With the exception of the exhaust manifolds and engine mounts, nothing will interchange. If you want to upgrade to the 496, you have to replace the complete engine. There are 496s sold on the internet which are NOT the modern GM 8.1, they are bored out 454s. They will interchange, but if you're going to do that, you might as well buy a new 454. Yes, you can still buy new 454 longblocks from GM.

If this is in fact a late model 8.1 GM engine, it has never been offered with a carb so other than maybe aftermarket, there is no intake manifold available for it to allow you to use a carb. It also is distributorless, so without the ECU, engine harness, coil packs, cam and crank sensors (which old style engines do not accomidate), throttle body, and several other key components, there is no way you can use this thing.

By the way, if you're still thinking carbarueter, I have a good used steam engine you might be interested in.

Rick"
 
"This is the URL for the engin

"This is the URL for the engine I am looking at.

http://www.perfprotech.com/store2/ProductDetails.aspx?productID=1815

Factory crate 496 with intake, coil packs sensors and injectors and rails. I would guess I need a harness and ecu and possibly an air flow sensor. I am a Master Porsche mechanic and could wire this up. I am just looking for maybe somebody who has done the homework for me and figure this out easier. They have plug and play units for 12000.00 but I think I can do it for less.

Thanks for your input.
Peter"
 
"Peter,
Even for a good marin

"Peter,
Even for a good marine tech, what you are proposing would be difficult and expensive. Almost nothing from your engine will fit the 496 engine (aside from the fact that they went to all metric fasteners on the 496). Some of the things that you would need;

Throttle body
IAC motor and plumbing
All cooling system components
Fuel system cooler, pumps, lines
Bell housing, flywheel and coupler
Wire harness, ECM
Pulleys, idlers, and belt

And by the way, all marine EFI systems are Speed/Density not MAF.

I would suggest replacing the 454 with a fresh 502 and using one of the aftermarket marine EFI systems (Fast, AZSM, Holley, ect)

Dave"
 
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