The above comments have merits up to a certain point. Economics do play into the grocery getting utility engine...
literally a couple hundred bux could up grade you to a V-8 car so why spend more on a small mill that won't approach
the big block at the time without spending the amount of money to make a V-8 anyway.
Right now a fair amount of modern vehicles run in the 9-10:1 SCR range, and some high end vehicles are running
up to 12:1 on the street. Part of this is the available technology and engineering knowledge that wasn't available
when our engine was designed and 20 years before that the vehicles going to war were using even lower compression
and using high drive ratios to keep the engine happy on petro that was crudely refined by todays standards.
An issue that does occur with engine longevity is the fact that when an end user goes from driving a stock 1 barrel
car to a hipo slant...a lot of aggressive driving ensues and it hammers the drive and powertrain shortening the life
of the build...on the top end, the guys wringing all the power out of the engine to get across the line faster are beyond
the original design specs and safety margin of the engine and it will wear out from repeated 1/4 mile runs. Routine
maintenance and less abuse will help things last longer...(along with good engineering when thinking out the build
and rebuilding the mill).
You shouldn't have any problems keeping a 9:1 SCR engine together for 100K+ miles in a daily driver as long as you aren't
hammering it light to light, or pulling repeated hyperpak clutch dumps...
10:1 SCR if thoughtfully put together will last a similar amount
11:1 and 12:1 can be streeted but the build will not be an MPG car and may not last as long as you will
be racing it a bit to see what it really can do.
Designing with the DCR in mind and adjusting the cam specs along with matching to the drive ratios and rpm
will help decide how much knock needs to be supressed with higher octane, less timing, or other methods...
NOx is a product of high cylinder pressure and temps...which will occur but can be lowered through use of
EGR, timing, catalytic convertors...it isn't even considered in race cars, but if the car is to be smogged, you
may need to keep it all stock to keep the regulating body happy and get your registration renewed.
Keep asking questions, hone in on what you want to achieve and build for the here and now.
(...and be thankful the Ford Nucleon didn't get built, we'd have had a completely different discussion
on engine longevity...LOL)
