1986 Cobalt 300 Condurre with Arnesons
06-11-2023, 01:05 PM
#1
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Thread Starter
1986 Cobalt 300 Condurre with Arnesons
New to me.
Orig owner bought in '87. Ran the 400 TRS drives for 87 hrs...one TRS failed...Merc wouldn't warranty it...so he put Arnesons on.
Twin 454BBCs with 420 B&M fed by twin 750 DP.
Not sure what the trannys are. They are not Velvets...but he said they were 750hp capable.
Needs some TLC. Sat since 1994.
144hrs on the hull.
Beautiful boat.
Needs upholsty.
How did these hulls perform at higher speeds?
Thanks,
Art
Orig owner bought in '87. Ran the 400 TRS drives for 87 hrs...one TRS failed...Merc wouldn't warranty it...so he put Arnesons on.
Twin 454BBCs with 420 B&M fed by twin 750 DP.
Not sure what the trannys are. They are not Velvets...but he said they were 750hp capable.
Needs some TLC. Sat since 1994.
144hrs on the hull.
Beautiful boat.
Needs upholsty.
How did these hulls perform at higher speeds?
Thanks,
Art
The following 6 users liked this post by Tartilla:
93 shooter (08-10-2023), hogie roll (06-11-2023), Holy Smokes (06-16-2023), larslindroth (09-09-2023), miller high life (06-15-2023), Twin O/B Sonic (06-11-2023)
06-11-2023, 03:52 PM
#3
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SO very cool!
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Baja 252 Islander
Baja 252 Islander
08-10-2023, 02:05 PM
#5
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Thread Starter
Moving the Cobalt to my primary res at the end of the month. Just finishing up my shop extension to house the 38ft with trailer overall...and still have room to service drives and walk comfortable past the trailer hitch.
Found that both 25hr engines are frost cracked. Unless I buy new GM Performance Gen VI blocks, I won't be able to use the current forged pistons that are 4.250" bore. Landed in Canada..the $2200 USD ish new blocks are over $3500 CAD. Better to source seasoned Gen VI blocks and use the original forged cranks...and put new tech pistons on. Maybe even new rods too.
The original forged flat tops should be the same as the Merc HP500s?
Replacing blocks have put a damper on the overall time expenditure, and budget.
Been looking for heat exchangers. Not a lot around used for the size I need. I want to do full cooling including the exh manifolds. Instead of going new $2000cad each heat exchangers...I think I'll go the stainless big rig EGR cooler fabrication method. Seems like the best long term option, and certainly far cheaper. May be some weight savings as well.
Still committed to run the 420s. I'm liking them more and more.
With the engines shoehorned into front firewall, and not sure how the hull rides with the weight forward...(also putting the cabin on a diet. Fridge and some of the drawer cabinets are gone) I'm not against putting extension boxes on. Even 6-8 inches would make a difference and be a hull tuning option.
Damn Cerrera ran with about 800hp as far as I know...that was from a post from Alex Picon on a photo of him and his Dad running SS9Ms, Alex had the quad 250 outboard.
I made the mistake of exposing the gelcoat behind the cockpit seats to the sun. They blistered a bit...but it's behind the seats. It also happened to the cockpit floor a bit as well..but not as obvious.
Found that both 25hr engines are frost cracked. Unless I buy new GM Performance Gen VI blocks, I won't be able to use the current forged pistons that are 4.250" bore. Landed in Canada..the $2200 USD ish new blocks are over $3500 CAD. Better to source seasoned Gen VI blocks and use the original forged cranks...and put new tech pistons on. Maybe even new rods too.
The original forged flat tops should be the same as the Merc HP500s?
Replacing blocks have put a damper on the overall time expenditure, and budget.
Been looking for heat exchangers. Not a lot around used for the size I need. I want to do full cooling including the exh manifolds. Instead of going new $2000cad each heat exchangers...I think I'll go the stainless big rig EGR cooler fabrication method. Seems like the best long term option, and certainly far cheaper. May be some weight savings as well.
Still committed to run the 420s. I'm liking them more and more.
With the engines shoehorned into front firewall, and not sure how the hull rides with the weight forward...(also putting the cabin on a diet. Fridge and some of the drawer cabinets are gone) I'm not against putting extension boxes on. Even 6-8 inches would make a difference and be a hull tuning option.
Damn Cerrera ran with about 800hp as far as I know...that was from a post from Alex Picon on a photo of him and his Dad running SS9Ms, Alex had the quad 250 outboard.
I made the mistake of exposing the gelcoat behind the cockpit seats to the sun. They blistered a bit...but it's behind the seats. It also happened to the cockpit floor a bit as well..but not as obvious.
Last edited by Tartilla; 08-10-2023 at 02:19 PM.
The following users liked this post:
larslindroth (09-09-2023)
