Slant 6 Turbo 68Dart Project

2 problems with that.

1. 198 slants are the rarest of slants, only made 4 years. Everyone has seen/heard of the Dutra article, and now thinks their 198s are worth their weight in gold, just for the rods.

2. The 2.2/2.5 engine family is like the slant. Old and obsolete. No one makes a forged motor for the 2.2 (or 2.5) anymore. Only Hyper cast pistons that I know of.

The long rod motor wouldn't provide you with much of a benefit really. Sure, lighter rotating assembly and more compression, but you don't really need either of those. By the time you got 198 rods and had them reconditioned, and then had a forged piston made, you'd be in the ballpark of the K1/Wiseco combo. Just a couple hundred under most likely. A stock rod/forged piston (even if it was custom) would be a better route IMO.

Also, keep in mind your newly acquired is a cast motor. Cast cranks have gone to 300 horse, but I think it's uncharted territory past there.

Some more thoughts:
Overbore: only bore as much as you need. Your machinist will be able to tell you that number. 80's motors are said to be thinner, I don't know yea or nay on that. Regardless, I wouldn't want to bore past .060 and look into a sonic check if it needs that much

Crank: Nothing fancy. It's a cast crank, you're not supposed to offset grind those I don't think. If it needs a little undersized, fine. Another thing your machinist will have to look at.

Rods and Pistons: like I've been saying for a while, I'd look at the FlatLander forged piston rebuild kit. Also, I'd shoot for a 8-8.5 comp ratio. I wouldn't dip below 7, it'd just make it a dog off boost.

Cam: No one really knows. *I* would say most lift you can get, first off. Then I'd say a 264* or smaller cam ([email protected] if measured that way) and no more than 40* overlap (or no more than [email protected]) Then (and lots will disagree here) I'd say don't necessarily worry about LSA. 111 or greater will work alright, it don't have to be 114+. LSA is only used to reduce overlap. That's it. Supercharged motors are the only ones that you have to worry about blowing the boost out the exhaust. The thing you have to worry about with a poorly designed turbo system is exhaust pressures being too high and coming back into the cylinder. If you don't know about your turbos that could be a problem, but if you don't push the limit that I said I think you'll be alright.

Oh, and I wouldn't rule out the hydro cam. Just think, no more adjusting valves!