Considering a Slant 6 swap into a Mitsubishi Starion...

Hello all.

I currently have a pair of 1980s Mitsubishi Starion/Chrysler Conquest cars. For those unfamiliar, there is no Chrysler in these cars at all. They're all either sold as what they are (Mitsubishis) or are rebadged as Dodge/Plymouth/Chrysler Conquests, depending on years.

They are factory-equipped with the G54B 2.6L 4-cylinder, TBI, single-turbo Mitsubishi motor found in a lot of forklifts and Dodge Caravans. Many of us in the StarQuest owners' groups end up swapping that motor out. I have a 1988 Conquest with the factory G54B still installed and have no plans to change it. But I have a 1986 Starion awaiting a swap, either to Mitsubishi's 6G72TT (Dodge Stealth/Mitsu 3000GT), Chrysler/AMG's M112 (Chrysler Crossfire) or a Slant 6.

The G54B came from the factory with about 180 hp and 230 torque. It's an odd motor, low-revving and almost acts like a straight six or big-block V8 in regards to power curve. So my baseline for a Slant 6 is that it has to at least match those numbers, and hopefully exceed them.

The one other requirement, given the StarQuest application, is that it must end up turbocharged. I would also strongly prefer it to be converted to EFI. This car will primarily be my wife's and reliability is a huge factor (a big reason I'm looking at the Slant 6 over the 6G72TT, especially).

I'm not saying budget isn't a factor, but it's a secondary factor to getting what I want. Ideally, I would like the motor to compare, numbers-wise, to the 6G72TT in factory trim. That would mean around 250 HP/320 torque at the end of the day. From what I've read, that's pretty doable on this motor.

Where I'm running into trouble is that most of the info out there on this kind of build is several years old now, and light on some of the details (what turbo specifically? what are my EFI options? can I retain an A/C compressor, which is a necessity in the South where I live?). I'd like to hear some general opinions on how to get to those target numbers, and having some idea of a budget would be nice, too. There is also the big issue of a transmission -- it MUST be a manual and I would prefer as many gears as I can get (the factory Mitsu unit is a 5-speed).

In the end, this is going to be a neat build. The Starion/Conquest twins are fantastic cars, great handling with an interior that was ahead of its time. The weight balance and nimbleness are fantastic. This car's ultimate purpose will be more for curvy-road driving than anything else; I'm not a drag racer. The car is about 3,000-3,200 pounds. I'm still on the fence about whether to use the Slant 6 or the 6G72TT, and one big advantage of the latter is I have cleaner transmission options and wouldn't need to modify the firewall. Any feedback is welcome.