Need Some Help with Engine for Pro Touring Build

[ALBERTAN]

I've been hemming and hawing about what motor to use in my PT build for months. With the frame now out of the car, and likely to be ready for powder coating in the next month or so, I need to make a final decision in case I need to change motor mounts. Let me start off with my goals, and then I'll list my considerations.

1. I want the car to make around 600-650 crank horsepower...no more. I've had (still have) cars with more power, and to be honest, they're not as much fun to drive IMO. I'm not looking for another point and shoot missile. I've talked to Mark Savitske about this at length and he agrees anything more is going to overpower the high dollar suspension mods I've invested in.
2. The car absolutely needs to be turbocharged, in keeping with the theme of the car. And it needs to sound turbocharged. I don't think an LS motor at 4 lbs of boost is going to qualify, although it might excel at point three.
3. I want to maximize the area under the horsepower and torque curves. This isn't going to be the typical drag race top end build. This car will spend 95% of the time under 4-5K rpm. I'd also like to get as much low rpm torque as possible, which of course ties in with the whole maximize the area under the curve thing.
4. I'm really working hard to keep the weight down on this car. So an aluminum block is highly preferred.

So that's it really. The intent is to build a street car that is capable of but sees limited track/autocross/road course time. I'm open to anything at this point, and have received "pushes" in various directions from several knowledgeable sources. Here are my thoughts at the moment. Feel free to correct any misconceptions.

1. Stock 109 block - It certainly can be done. I'm not sure about reliability, and I'm not sure where it comes in cost wise by the time you girdle it and everything else. If I can be convinced this build will be low maintenance I'll try it. But I'd rather make sure I've got it right the first time.
2. 4.1 - I think this would increase the reliability. What the availability of these blocks is currently, and where it fits in cost-wise with the other options, I'm not sure...
3. Stage 2 - Never really crossed my mind. I'd go with a TA aluminum block first.
4. TA Aluminum block - I've already talked to Nick about going this route. It's probably overkill for what I am looking to accomplish. But the reliability and weight savings can't be beat. It's long been my first choice if staying V6. But again, am I spending money needlessly?
5. LS swap - I'm actually quite open to this. The problem is, any build I think of is going to make too much power. Low end torque definitely wouldn't be a problem though.

I don't need the details of the build at this point, although I'm sure I'll get some as a justification to go one route or the other. At this point, I'd just really like to make a decision and move on. Analysis paralysis. Thanks for the help.

 

[3-5.0]

V6 Turbo. In a general sense I'm not against another type motor and have even considered it myself (while cursing) but the whole point, mystique and legacy of these cars -real Turbo cars- is just that a V6 Turbo and doing it right and getting what you want with it is a BIG statement. Carving up a base Regal is a different thing.

 

[Nick Micale]

My obvious first choice would be an alum 4.1.

Second choice would be a LSA conversion with a 4L80-E which I have also done, but the cost would then triple!

Low end/mid-range torque and response would be about the same with either build, and even a 4.1 production block would be just as reliable at the 600-650 crank HP level as we have proven this many times.

 

[ALBERTAN]

Thanks Nick. I'll call you sometime this week to sort out a few more details.