Mercruiser 228 repower with truck engine

jdaghir

Seaman Apprentice
Joined
Apr 1, 2010
Messages
45
Hello, long-time lurker, first time poster here. Please be gentle with me.

I've got a 1979 Century 3000 19' bowrider. It is currently powered with a Mercruiser 228 - a SBC 5.0L with a Quadrajet and a pre-Alpha outdrive. Interior is in good shape, outdrive is functional, deck is sound, transom is good as far as I can tell, stringers are questionable. I have owned the boat for 4 years now and have been pleased with it. However, last season it was accidentally ran while 3 quarts low on oil and now it knocks horribly and runs like crap. I believe it has spun a bearing or done some other terminal damage to the lower end.

The boat isn't worth doing a proper repower with a crate engine in my opinion, but I do like the classic lines of the boat and it suites my needs. I was given a supposedly running SBC 5.7L from a 1979 Chevy K2500 truck and would like to swap it for the wounded 5.0L and get a few more years of life out of the old gal if I can do it without spending thousands of dollars and 100 hours of time.

From my research on this forum and others I believe this should be doable. I understand the truck cam in the 5.7L may not be a perfect match for a real marine cam, but since I would be stepping up from a 5.0 to a 5.7L, I think it will do okay.

I think I will need to reuse the following from the 5.0:
alternator
starter
exhaust manifolds
distributor
water pump
carb
Fuel pump
Oil Pan
oil pan baffles
Dip Stick & Tube
flexible coupling
engine wire harness
engine mounting brackets

I will need the following new parts:
marine intake & exhaust gaskets
brass freeze plugs
transom gasket if I remove the gimbal housing to do an inspection/repair if needed on the transom
epoxy and fiberglass if the stringers need work

I will need the following special tools:
Mercruiser factory service manuals #3 & #4
Mercruiser engine alignment tool
timing light
torque wrench

Am I forgetting anything? Any other words of advice or tips/tricks you can share?

Thanks!

-Jeff
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Mercruiser 228 repower with truck engine

Here's your factory manuals...

Engine manual #3
Drive manual #4

Have a look in the engine manual at the timing curves for the 228 and the 260, they might be different, so you'll need to change either the weights and spring (for a points system), or the ignition amplifier (for HEI system). On that it might be cheaper to just change to a Voyager distributor.

For the carb, again check the specs for jet sizes etc..

If you are dead keep on the camshaft, the one in the 228 (305) is the same as the 260s (350) run. ;)

Just one more thing... You have an MC-1 drive, not a pre-alpha (no such animal)... :)

Chris........
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Mercruiser 228 repower with truck engine

Just checked the timing curves, they are the same, so no dramas there, but if it's points (I suspect it is), then I'd seriously look at THIS... But it does look like you might need to do some adjustments on the carb... OR replace it with a nice new Edelbrock 1409... :D :D :D

Chris......
 

jdaghir

Seaman Apprentice
Joined
Apr 1, 2010
Messages
45
Re: Mercruiser 228 repower with truck engine

But it does look like you might need to do some adjustments on the carb... OR replace it with a nice new Edelbrock 1409... :D :D :D

Chris......


Thanks for the manuals and the advice, I appreciate it greatly. Based on this thread at the Hull Truth I was hoping I wouldn't have to mess with re-jetting:

Quadrajet 5.0 rejet to 5.7 can't find specs - The Hull Truth - Boating and Fishing Forum



If the swap goes relatively trouble-free and within budget I'll seriously consider upgrading to the electronic distributor.

I'll post back as I get further into it - I'm sure I'll have more questions.

Thanks again!
 

dan t.

Lieutenant Junior Grade
Joined
Feb 28, 2008
Messages
1,131
Re: Mercruiser 228 repower with truck engine

1990 merc 350 Magnum carb # 17080562

primary jet--69
primary rod--35 with a 25 tip
secondary rod--ch
secondary hanger--g


Volvo 350 260 hp carb # 17059298

primary jet-- 69
primary rod-- 40b
secondary rod--cj
secondary hanger--j

Hope this helps, good luck with your swap
 
Last edited:

bonzoscott

Senior Chief Petty Officer
Joined
Jul 26, 2008
Messages
745
Re: Mercruiser 228 repower with truck engine

Worth exploring more - not sure you need new oil pan or baffles. you may be able to swap with the 5.0. Try to minimize impact of $.
 

2005bay

Cadet
Joined
Apr 15, 2012
Messages
18
Re: Mercruiser 228 repower with truck engine

It would be pretty easy to swap that cam in while the motor is on a stand with the intake off... only a few more bolts and one cheap gasket. Might be worth having a look at the timing chain too.
 

dan t.

Lieutenant Junior Grade
Joined
Feb 28, 2008
Messages
1,131
Re: Mercruiser 228 repower with truck engine

It would be pretty easy to swap that cam in while the motor is on a stand with the intake off... only a few more bolts and one cheap gasket. Might be worth having a look at the timing chain too.

+1 on that, and change the front crank seal while yer at it.
 
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