Go Back   TeamTalk > Maintenance Tips, How-tos and Refurbishing Topics > Engine / Drive Train

Reply
 
Thread Tools Display Modes
  #1  
Old 04-12-2018, 06:56 PM
Copcraft Copcraft is offline
TT Newbie
 
Join Date: Nov 2017
Boat: 1974 Correct Craft Mustang
Location: Midwest
Posts: 11
LT1 vs LT4 ?

I am hoping I can get some help here. I just purchased a 1996 Prostar 190 with the LT motor with the understanding that the motor needed to be rebuilt. It had not ran for 8-10 years, and previous owner thought water got into the valves while winterizing? I have no knowledge of engines whatsoever. We pulled the engine yesterday. Upon getting it on the stand, water was dripping from the interior of the motor. We tried draining the oil using the long drain tube, however nothing but a small dribble came out. Upon disconnecting the tube from the oil pan, a large thick white booger dripped from the motor. After coaxing several of them out, we were able to get a stream of milky oil to drain and almost fill the pan on the ground. Mechanic called today and stated that he thought the engine was going to be too far gone to rebuild. We ran the number on the engine block and it is a LT4. I have access to a good running LT1 motor that was pulled out of a car. Can I swap the electronics, manifolds, put the boat transmission on and put this in the boat? The LT1 supposedly has 285 hp vs the 330hp of the LT4. Thoughts? I have no idea where to turn.Thanks.

Last edited by Copcraft; 04-12-2018 at 08:01 PM. Reason: Duplicate message
Reply With Quote
  #2  
Old 04-12-2018, 10:15 PM
1redTA's Avatar
1redTA 1redTA is offline
MC Devotee
 
Join Date: Aug 2009
Boat: 1981 MasterCraft 351W slot
Location: Pace, FL
Posts: 1,454
yep, the LT4 block is a 4 bolt main versus the 2 bolt lt1
__________________
1981 MasterCraft
19' Skier 351W PowerSlot
Long gone is the Trans AM waiting for another
Reply With Quote
  #3  
Old 04-13-2018, 11:41 AM
Copcraft Copcraft is offline
TT Newbie
 
Join Date: Nov 2017
Boat: 1974 Correct Craft Mustang
Location: Midwest
Posts: 11
So the LT1 should work in place of the LT4, just less hp?
Reply With Quote
  #4  
Old 04-13-2018, 11:57 AM
allzway's Avatar
allzway allzway is offline
TT Enthusiast
 
Join Date: Jun 2016
Boat: 2016 NXT22
Location: Texas
Posts: 164
In terms of LT1's in Camaros and Corvettes, yes they are the same. The biggest difference was in the cam and heads and produced something like 30 more HP.

http://www.grandsportregistry.com/lt1vslt4.htm
Reply With Quote
  #5  
Old 04-13-2018, 12:55 PM
Shaun R's Avatar
Shaun R Shaun R is offline
MC Devotee
 
Join Date: Jun 2014
Boat: 2011 X25
Location: Austin, Texas
Posts: 1,684
Camaro/Firebird LT1 is a 2bolt block, Corvette LT1/LT4 blocks are all four bolt. LT4 had a larger cam, bigger heads with different intake angles that required the red intake manifold, and a better harmonic balancer to handle the higher RPM motor. All LT4 parts will bolt directly to and LT1, only gotcha is you have to match the heads with the correct intake manifold as the runner angles are different.

If the LT1 you have is rated at 285, it's most likely out of an fbody. Take the pan off and look at the main caps to be sure.
Reply With Quote
  #6  
Old 04-13-2018, 01:35 PM
Copcraft Copcraft is offline
TT Newbie
 
Join Date: Nov 2017
Boat: 1974 Correct Craft Mustang
Location: Midwest
Posts: 11
Great! Hopefully I can just get away with switching the LT4 stuff over and having it all work.
Reply With Quote
  #7  
Old 04-13-2018, 01:44 PM
Shaun R's Avatar
Shaun R Shaun R is offline
MC Devotee
 
Join Date: Jun 2014
Boat: 2011 X25
Location: Austin, Texas
Posts: 1,684
Also, Most machine shops can convert a 2bolt to a 4bolt for a reasonable cost
Reply With Quote
  #8  
Old 04-13-2018, 01:49 PM
Cumminscj Cumminscj is offline
TT Enthusiast
 
Join Date: Oct 2016
Boat: 86 Magnum Skier
Location: Southeast
Posts: 257
Don't forget to swap the freeze plugs out and the head gaskets.
__________________
1986 Marlin Magnum Skiier-sold
2000 Maristar 210VRS-weekend ride
1996 205 with LT1 cracked block-winter project
Reply With Quote
  #9  
Old 04-13-2018, 01:56 PM
Table Rocker's Avatar
Table Rocker Table Rocker is offline
MC Devotee
 
Join Date: Oct 2010
Boat: '96 ProStar 205, Sammy Duvall, LT-1
Location: Fayetteville, Arkansas
Posts: 2,460
Is anyone else surprised to hear of an LT4 in a '96 ProStar? I thought LT4s were fairly rare and only used in Grand Sport Corvettes in '96 and '97 special edition Camaros and Firebirds. Isn't it most likely that the engine that was in his boat was the factory LT1?
__________________
'96 ProStar 205 SD LT-1
Reply With Quote
  #10  
Old 04-13-2018, 02:01 PM
Shaun R's Avatar
Shaun R Shaun R is offline
MC Devotee
 
Join Date: Jun 2014
Boat: 2011 X25
Location: Austin, Texas
Posts: 1,684
Quote:
Originally Posted by Table Rocker View Post
Is anyone else surprised to hear of an LT4 in a '96 ProStar? I thought LT4s were fairly rare and only used in Grand Sport Corvettes in '96 and '97 special edition Camaros and Firebirds. Isn't it most likely that the engine that was in his boat was the factory LT1?
Block casting numbers between the Corvette LT1 and LT4 are the same, but the 2 bolt has a different casting number. I assume it's the original Corvette LT1 block but can't tell without seeing it. Pull the valve covers off. If the rockers are stamped steel then LT1, if aluminum rollers with a little bowtie on them, it's an LT4.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 12:08 AM.


2018