454mag to 496 volvo
 

If I swapped out my 454 mags(1988) for Volvo 496 efi engines, what would need to be changed? Thanks

Re: 454mag to 496 volvo
 

Anyone? i know some board members did this swap.

Re: 454mag to 496 volvo
 

I just read in a post that the 496 engines need a 10 pin harness to plug in. My 1988 454 mags have a five pin harness. Would this be a problem? What is involved in changing the harness?

Re: 454mag to 496 volvo
 

MT, Pat McPherson on here did the switch awhile back. Try Pming him. Hope you don't mind Pat.

http://www.offshoreonly.com/forums/m...hp?userid=6454

Re: 454mag to 496 volvo
 

I dont mind pat. he seems like a nice guy. :D

Re: 454mag to 496 volvo
 

Ok how about this. If going from 454/365Hp carb motors to 496/375efi or 496/425 efi what kind of speed increase would I see with a 1988 38ft stinger?

Re: 454mag to 496 volvo
 

Hate to put it so bluntly but there won't be a whole lot of diffrence at all. I wouldnt even consider the 375 model, go straight for the 425 and I think if you would be lucky to see 5 or 6 MPH on the top end, deffenitly better midrange and fuel economy with the 496 though and there is also the turnkey reliablilty factor of EFI .

Re: 454mag to 496 volvo
 

I figured the 375hp wouldnt do much for me. I dont know the torque specs of a 496/375 vs 454/365, but I would think the 496 would have more torque.

Re: 454mag to 496 volvo
 

I'm sure someone around here has had one on dyno. merc is pretty secretive about the #'s all they will give is HP.

Re: 454mag to 496 volvo
 

Someone told me the 375Hp dyno's near 390, but for marketing purposes, merc advertises them as 375. Dont know if thats true or not.

Re: 454mag to 496 volvo
 

You would have to change out your harness from the helm to the motor, use the complete engine and drive harness from the volvo motor , a Merc 496HO or get a complete MEFI set up from Flagship or Arizona Speed & Marine. The exhaust will interchange straight across, but if you have the old style log manifolds I would opt for a new exhaust system, many BBC types to choose from in all price ranges. Should not be a difficult change out for a motivated boater/gearhead. Make sure the drives are up to the new horsepower and torque levels of the 496HO level. The stock 496HO makes 420-425HP on the dyno and the torque comes in about 480 ft./lbs at 3900 rpm.
Hope this info helps.
Ray @ Raylar

Re: 454mag to 496 volvo
 

I was told by some my stock boats harness will plug into the new motors harness. The motors are completly wired. Is this true?

Re: 454mag to 496 volvo
 

I had a 93 454 and mine plugged right up. It is a great swap.

Re: 454mag to 496 volvo
 

Did you go with the red engine? How was the drivabilty after the swap?

Re: 454mag to 496 volvo
 

Yes I went with the red engine. If you look in the classified section there are some more of these engines available at great prices. You use your old coupler, bell housing and engine mounts be sure to use metric bolts on the coupler. I picked up 14 mph.