SHO V6 swap into Triumph Stag

Old Man

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Hello all,
A little over a year ago I bought a 1973 Stag. (Google it) It is a fairly rare car and more so in the U.S. It was born with a 3.0 V8, built by Triumph. These engines had some issues and would overheat, often fataly, so swapping engines into them is not uncommon. A previous owner had put an early 80s GMC 3.8 V6 in tha one I bought. It still runs, but it is time for an upgrade. After researching all the options I could think of, I decided that a V6 SHO was what I wanted. Reading threads on this forum helped me make that decision and I am hoping that with a little more help, I can make this happen. Some of the threads I found helpful involved Offroad SHO (Tom). If you are still out there, thanks for the information and I hope you will be available for some Q&A
 

luigisho

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Do you have room for the sc 3.8 from the 2000's? It will bolt right up and get you extra hp and low end torque. I miss my old GTP. Plus those motors are everywhere for parts. THe Iron Duke 3.8 is one of the best engines produced in a long time. Need even more power? drop a pulley size. more room to play with for power right out of the box
 

zoomlater

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Here is a post from someone who was also looking for parts.

 

Old Man

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Upgrading to a more modern 3.8 was definitely under consideration. It would be infinitely easier and cheaper, and with tons of parts and after market. I want a high revving engine and I think the V6 SHO is nearly perfect for what I want. And, it is rare and unique like my car.
 

yaycandy

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Check some yards for a rwd 5 speed aerostar transmission. It looks like a good bolt up but not sure what else is needed from it
 

rubydist

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Sounds like great fun. The SHO engine is tall and wide, so check the dimensions first to make sure you have room in the engine bay to make it fit. I've found size issues in each of the vehicles that I have considered swapping a SHO motor.
 

Mike Spataro

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Sounds like great fun. The SHO engine is tall and wide, so check the dimensions first to make sure you have room in the engine bay to make it fit. I've found size issues in each of the vehicles that I have considered swapping a SHO motor.
Hello
There is a member with exactly what you need posted on Craigslist Harrisburg Pa. He has plenty of early SHO parts forsake. Hope you have fun installing it in the Stag.
 

zak

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If you search here there is someone that modified the stock oil pan and pickup (cut and weld) for better steering rack/front cross member clearance, fairly recently.

The height is an issue with a swap candidate I've had in mind, despite the crank centerline to top of intake manifold being very close to numbers published for the Chevy LS (which has been put into everything). Of course a SHO motor is several thousand dollars less than an LS motor.
 

TitanFox

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I like your idea lol. The bellhousing and Trans is the biggest problem to get through and car specific restrictions. But the Facebook sho group has a possible group buy for an adapter plate. The aerostar housing is a tough one. I've called many places that claim to have one and dont. I will be posting a build thread when I start mine and I'll be share all the info I can to help others out. Good luck with the project.
 

luigisho

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Those aerostar housings are getting harder to find. Maybe a nationwide used like LKQ? THere are used part search engines on the interwebs you can try. Older stuff is drying up
 

DadMobile

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the Gen 2 Raptor 3.5L has more parts, power, and potential from the 3.5 than the SHO. For example, you can get a cam for the Raptor motor! Just throwing out an alternate :)

tuners are pulling pretty wild numbers with the Raptor engine, like 550hp on gas.
 

Old Man

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I am sure that is a great engine. The biggest concern is ECU. I am looking for as little engine management as possible. I don't want to spend thousands of dollars on trying to make the original work or buying an after market ECU and paying to have it programmed. I have no interest in ECU tuning. I am going for NA as well, so no turbos. I don't need big numbers. This is a vintage British sports car that had 150 HP and 170 lb ft of torque. I am not planning on racing this car, so anything in the 200 to 250 range for both will make it very fast and very drive-able.
 

DadMobile

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For sure! A friend of mine has one back home. Awesome little car!
 

rubydist

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Yeah the m5od will hold up fine to the power and torque of the n/a SHO motor, although they do not shift particularly well. That would be much easier than trying to find a bell housing, if you can deal with the shifter location.
 

Old Man

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I would like to keep the stock transmission and drive line. It will not be as strong as I would like, but if driven with care, I should be fine. A stronger transmission, differential and drive line may be a project for the future, but I am not concerned with that for now.

I would like to make an adapter plate that will allow me to bolt the stock bell housing to the SHO. How impossible is that? Can I change the fly wheel to mate with the clutch size I need?
 

rubydist

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Its possible to make an adapter to make nearly any trans fit up to nearly any engine, but its not necessarily cheap or the best strategy. You could change the flywheel, but it would basically mean having a custom flywheel made. I think you will find that changing the trans and driveshaft to ones that fit with the SHO motor will be significantly less work and less cost than the custom adapter / flywheel idea. I think you will be changing the driveshaft anyway, because the odds of you having the trans end up in exactly the same spot with the different engine are very slim.
 

Old Man

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Hello all,
I have found two 3.2 V6s that will work. I am ready to buy an engine and get started. Since I am putting it in front of a 5 speed should I use the ECU from a 3.0 MT
 
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