Building a high altitude 2.7 engine

[Rotmilky]

I'm wanting to build up a 2.7 to put in the 68 coupe I'm restoring. I've got Wayne's book and Bruce's book and am going through them with a fine tooth comb. Between those two and this forum, I felt like I would be able to find most of the information I needed to build a nice street engine with something like 190-200 hp (using 40IDAs that are original to the car).

The one concern I have is that almost all the literature and posts are for engines built at sea level. I live at 7500 ft, with daily driving ranging from 6000-8000ft. Monthly extremes would be 5000 on the low and 9500 on the high. The gas available at these elevations is something like 91 octane at best, so I have some concerns about building an engine that would require high octane levels. That said, since the pressure is lower, I'd assume the compression of the pistons would drop as well...so a 9.5:1 JE piston might be, shrug, 8.5-1 at this elevation (I just made that number up..but the density of air is lower to start with, so I just assume the final compression has to be lower).

I did find one post with someone from Albuquerque running a 2.7 with solex cams and 9.5:1 JE pistons (ABQ is ~5000 ft). I'm assuming there are a number of guys from Denver that could chime in as well. I don't know that the extra 2500' I live above Denver/ABQ would make a huge difference.

So...any thoughts/suggestions for an engine that is going to operate at these altitudes? Can I just take any of the forum advice, or Waynes suggestions, and assume it'll work with a resulting loss of power due to the elevation changes?

[5:04]

I bought the car you're speaking of. He raced it at that altitude and up to 7,000 iirc. He dialed in the carbs perfectly for the elevation and did well from what I heard. I have since changed the jets for here in CA and the car screams. I can tell you that everyone that gets in my car is shocked at the power my small 2.7 puts out.