Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

12" White Stickers
BallOfSpray $5 Donation
BallOfSpray $10 Donation

Remanufactured Engines Recommendations?

georgertgeorgert Posts: 4 New Baller
I fried the motor of my boat this summer. It is a Mercruiser 5.7 liter Competition Ski engine. I am going to need to replace the block, although the cyclinder heads, and all the other bolt-on parts are in good shape. Does anyone have any experience with or recommendations for any companies who sell a remanufactured engine that I can have shipped to Salt Lake City? Thanks.


  • skihackerskihacker Posts: 317 Baller
    Way back in the day the first call was usually discount inboard marine.
  • JetsetrJetsetr Posts: 322 Solid Baller
    edited October 10
    5.7 Long Block appx $2400 rebuilt 1 yr warranty
    NEW Marine long block from GM $2900 2yr warranty
    shipping available...

    Purchased a new GM long block for my Malibu.

    If it needs a just short block how do you know the heads are good? Depending how bad you “fried” your motor you may have damaged the heads as well. Have the skills to build a short block to a turn key unit?
    Lot easier to bolt on the intake, distributor and accessories and go skiing with a warranty.


  • Orlando76Orlando76 Posts: 1,060 ★★★Triple Panda Award Recipient ★★★
    @Jetsetr not doubting you, but where are you getting a new long block marine GM for $2900?

    I’ve had a few rebuilds between boats and trucks. Jasper, ATK from Summit, local “high end” rebuild, and on most previous rebuild for my 93 SN I opted to go with an ATK again as I’ve felt they were the best so far.
  • JetsetrJetsetr Posts: 322 Solid Baller
    edited October 11

    Michigan Motorz....
    For my boat the part number is 5700-preV 1987-1995 pre Vortec Head 275 HP
    The info above is for the 1986 or older 5.7 same price as my engine.
    Not sure which year he needs an engine wasn’t mentioned.
    The newer engines with aluminum heads are more expensive...

    Looked at ATK as well...
  • Mateo_VargasMateo_Vargas Posts: 849 ★★★Triple Panda Award Recipient ★★★
    I just purchased a new long block from Michigan Motorz. Boat is running great.
    Success is failure that just hasn't happened yet
  • oldjeepoldjeep Posts: 3,424 Mega Baller
    X3 Michigan motorz, buy a long block. Not worth screwing around hoping that your ancient heads are actually good
    Chuck P
    Not a mechanic but I play one at home
  • georgertgeorgert Posts: 4 New Baller
    I appreciate everyone's comments. The reason I believe the heads to be good is because the shop pulled the heads, replaced the valves and had the heads ground thinking that the sole issue was warped heads and blown cylinder head gaskets. However, once it was started back up the engine is knocking so the thinking is that there are other problems with the rods/bearings, etc. The recommendation was to keep the heads (and all the other parts and just get the basic engine block and guts. If anyone has any other thoughts on the matter, please dive in.
  • oldjeepoldjeep Posts: 3,424 Mega Baller
    edited October 11
    The fact that your shop did that and thought that indicates you need a new shop. Get a long block, and enjoy having a new motor that was rebuilt properly
    Chuck P
    Not a mechanic but I play one at home
  • JetsetrJetsetr Posts: 322 Solid Baller
    edited October 11
    If it was knocking (rod bearings/wrist pins) prior to having the heads worked on it’s definitely time for a new shop...

    Steel heads are not worth much...use them as book ends (or launch them thru the window of the shop that took your money for work that didn't solve the problem) and get a new or reman long block with a warranty. Depending on your plans for the boat (keeping it a long time or selling sooner than later) would be my factor between new or reman. I’m my case the boat only has 304 hours so for $500 more new was the way to go.
  • Dacon62Dacon62 Posts: 697 Crazy Baller
    edited October 11
    5.7-86 Mercruiser was 260 HP carbed.
    5.7-2000 Scorpion was 330 HP.
    Assume Cam, heads, EFI upgraded.
    Guess it depends on how much HP you want and how much you want to spend.
  • Stevie BoyStevie Boy Posts: 2,021 ★★★Triple Panda Award Recipient ★★★
    Cheapest is not always best, save yourself the aggravation buy a long block, depending how far out you are, it's a long way to paddle.

    When The Going Gets Tough, Get Stoked !

  • Keith MenardKeith Menard Posts: 554 Crazy Baller
    Do you guys ever go higher up when replacing the engine?
  • ReallyGottaSkiReallyGottaSki Posts: 69 Baller
    Helz ya
  • DWDW Posts: 2,020 Mega Baller
    @Keith Menard - Yes, bumped hp up quite a bit and went all aluminum.
    @georgert - what year is your boat / engine? If pre '96 it will have old style heads so 240 hp, if '96 or newer, 310 hp Vortec heads. That may influence your decision, along with the question of who is going to assemble a short block > full engine for you.
  • JetsetrJetsetr Posts: 322 Solid Baller
    edited October 16
    My 1993 5.7 GM “Magnum” carb engine is 275Hp (same as the FI engine), my 1989 Ford 351 carb engine is 240hp...

    The standard 5.7 GM is 260Hp.

    Significant bump in Hp (less weight as well) for the Vortec also have to use the transmission adapter for the old style transmissions (automotive I KNOW you do, assuming (dangerous) you do for the marine application as well) if you go to the Vortec engine, different exhaust manifolds and of coarse you need all the electronics. Gets pricy FAST...but a fair Hp boost.

    But it’s VERY easy to build a standard 5.7 to well over 400Hp on pump gas...
    That also opens another whole can O’Worms, because now you have to re-prop ($$) to take advantage of the horsepower your making...

    Comes down to how much $$$$ you want to spend...

  • DWDW Posts: 2,020 Mega Baller
    @Jetsetr - I am sure you know one can do a Vortec style head update and stay carbed (if the current one is) via aftermarket heads with both intake manifold bolt patterns. You can also mod the exhaust manifold ports to fit a bigger exhaust port if needed. You do have to tune the prop to match the hp output. (typo on my part on the standard SBC hp, was simply pointing out the power difference between the old / Vortec heads). Where are you seeing the weight savings on the Vortec heads? Assuming you are thinking aluminum parts.
  • ReallyGottaSkiReallyGottaSki Posts: 69 Baller
    Regarding prop one can usually best stay the same, just let the engine breath and spin and make power. Metalugrgically a std small block bottom end is good for 5500 rpm all day, with maybe premium rod bolts for insurance if it feels better to do something to it. building a stroker is usually the delineation point for addressing prop, higher available torque at all rpms and to keep piston speeds in check, benefit from more bite.
  • JetsetrJetsetr Posts: 322 Solid Baller
    edited October 16
    @DW yes, you’re friend was going to donate a LS-1 for my boat...was confusing LS-1 vs mistake....

    I thought about it for about 3 minutes and decided to stick with the 5.7 Magnum. A lot of messing around to marine-ize the LS-1-cam, exhaust, trans adapter, electronics etc etc...
  • DWDW Posts: 2,020 Mega Baller
    @ReallyGottaSki - you can also overcome the prop on the air side, via cam and heads even while staying at standard stroke.
Sign In or Register to comment.