Stinger 390x Repower
10-17-2013 | 07:37 AM
#1
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From: Cumming Ga
Stinger 390x Repower
I have an '83 Chris Craft Stinger 390x . I am at a point where i am looking to possibly repower the boat. It has twin 454 with unknown hp and average 350 hr on both. The boat is running BW transmissions and TRS outdrives.
I have owned the boat for little over a year and pulled the boat to paint the bottom and do all other service. Upon pulling the boat, I found that the drives were pretty chewed up. I then found a set of rebuilt TRS drives in CT and went and picked them up. I was having issues with one of the engines towards the end of the season. SO in pricing to have the engine rebuilt i started wanting to repower the boat. Stock spec on the boat is twin 400hp 454 the boat is rated to do 65mph with this set up. I am wanting to be in the upper 70's to low 80's. I am trying to figure out the most cost effective and best bang for my buck. I have looked into 502ci engines that i can get turn key 515 hp for 7k is an engine. or can buy 502 and put a 540 kit in it. I have also seen several boats running the merc 525. anyone have experience with these? The main concern is if the BW trans will hold the power. I was told that over 500hp the Trans starts to fail. If that is the case, Then can i beef up this trans or is there a step up that will hold the power? I have read extensively that the TRS outdrives are great bullet proof drives but i dont want to do all this work and have it fail in the water...
I would appreciate any help or ideas.
Thank you
I have owned the boat for little over a year and pulled the boat to paint the bottom and do all other service. Upon pulling the boat, I found that the drives were pretty chewed up. I then found a set of rebuilt TRS drives in CT and went and picked them up. I was having issues with one of the engines towards the end of the season. SO in pricing to have the engine rebuilt i started wanting to repower the boat. Stock spec on the boat is twin 400hp 454 the boat is rated to do 65mph with this set up. I am wanting to be in the upper 70's to low 80's. I am trying to figure out the most cost effective and best bang for my buck. I have looked into 502ci engines that i can get turn key 515 hp for 7k is an engine. or can buy 502 and put a 540 kit in it. I have also seen several boats running the merc 525. anyone have experience with these? The main concern is if the BW trans will hold the power. I was told that over 500hp the Trans starts to fail. If that is the case, Then can i beef up this trans or is there a step up that will hold the power? I have read extensively that the TRS outdrives are great bullet proof drives but i dont want to do all this work and have it fail in the water...
I would appreciate any help or ideas.
Thank you
10-17-2013 | 08:09 AM
#2
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Joined: Jul 2004
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From: chicago
Ok, you may not want to hear this, but I'd rather not blow smoke up your azz.
#1. With 400HP 454's, I can tell you the stinger 390 will NOT hit 65mph. 60 at best on a good day.
#2 TRS drives are far from Bulletproof
#3 525HP a side will not get you anywhere near upper 70's-80mph.
#4 The B/W can be upgraded to handle whatever power you want. The drives are the weak link.
With that being said. You may want to look into NEW engines. If the blocks and heads are original to the boat, they are 30 years old, and probably borderline rotted away, even with freshwater use. There are lots of great engine packages for sale here on oso . To hit 70mph, you're gonna need around 600HP per side. Like a pair of 540CI mills. Those boats came with twin 330HP, twin 370HP, and twin 400HP engines. Can you post a picture of them, along with the transmissions, to be sure you even have the borq warner versions? The did make a merc trans back then that isn't very HP friendly.
#1. With 400HP 454's, I can tell you the stinger 390 will NOT hit 65mph. 60 at best on a good day.
#2 TRS drives are far from Bulletproof
#3 525HP a side will not get you anywhere near upper 70's-80mph.
#4 The B/W can be upgraded to handle whatever power you want. The drives are the weak link.
With that being said. You may want to look into NEW engines. If the blocks and heads are original to the boat, they are 30 years old, and probably borderline rotted away, even with freshwater use. There are lots of great engine packages for sale here on oso . To hit 70mph, you're gonna need around 600HP per side. Like a pair of 540CI mills. Those boats came with twin 330HP, twin 370HP, and twin 400HP engines. Can you post a picture of them, along with the transmissions, to be sure you even have the borq warner versions? The did make a merc trans back then that isn't very HP friendly.
10-17-2013 | 08:32 AM
#3
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Joined: Jul 2009
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From: Taunton Ma
Could also have 71c Borg Warner's that aren't worth trying to upgrade.
My hawk has a very similar bottom, with tweaked 525's And bravos i hit 68.8, no where near your goal. As mild thunder said, trs drives will not stand up to the power that hull will need to get to high 70's.
My hawk has a very similar bottom, with tweaked 525's And bravos i hit 68.8, no where near your goal. As mild thunder said, trs drives will not stand up to the power that hull will need to get to high 70's.
