[jhein]

As mentioned, I would think about a mild stroker. It sounds like you have a solid block/foundation. So a few extra HP won't stress it. A cast stroker crank is not crazy expensive.

But the real reason is the way you want to use it. If you want to stick with the stock tranny, and you want cruise at 70 mph, that 3000 rpm will get old fast. A stroker will allow you to tolerate a taller rear gear better. I think at the very least you'd want a 3.08 or really even a 2.73 or 2.56? With my rear at 3.31 and TKX OD at .81, I have a final drive of 2.68. I can do 75 mph at about 2600 rpm and 70 mph at about 2300 rpm. It's comfortable, but I wouldn't do any less if that's how you drive all the time.

So what I think I understand is that you want have this car as a daily driver. If that means regularly cruising at 70 mph, then what you really need is a OD trans.

But I also understand your desire to keep it all original. So there's your dilemma right there.