The ideal compression for a given combination and grade of fuel is determined by a number of factors, which include but is not limited to the head design, material (iron or aluminum), and camshaft profile. I know enough about it to get in trouble so I'm not going to try to get all technical about it. A static ratio of 10:1 absolutely could be what is required for a given combination. It also could be too high or too low. You really can't know until you have your build planned.
Here's a link to a dynamic compression calculator which is really what is important. I think this calculator only applies to iron heads.
http://www.projectpontiac.com/ppsite15/ ... calculator
The dynamic ratio is needed to determine the grade of fuel required. I can't find a chart with a quick google search, but I'm sure one is out there.
Ah, not a chart but here, Ted Eaton has a limit of 8:1 dynamic for 91-93 octane. I assure you, he knows what he is talking about.
http://www.y-blocksforever.com/forums/T ... -3-1.aspx?
According to that calculator and Ted's opinion of 8:1 dynamic, I could run 10.6:1 static with my combo and be fine with premium. But my future includes boost so I'll stick to the plan. That calculator comes up with 9.73:1 as my current static ratio, and 7.37 dynamic. It is a little high in my case because of the shape of the gasket. I get 9.45 when I do the math by hand.
Camshaft, I don't know. Mine is a reproduction of a '57 blower cam. Certainly not new tech and definitely not a low end power grind like an RV cam. I was told that mileage would be terrible , and I didn't really care, but with the rest of the combo, that is simply not what happened. When I do it again, I'm going to call My Favorite Cam Grinder, Inc. and tell them what I'm doing and let them decide on the grind. That really is the best bet but you need to make a plan for the engine build and stick to it.
I'll reiterate that I did not build mine for economy. I just want it to go faster. It just so happens that the mileage increased as well. I'm sure the compression increase helped a lot. Even a '57 292 with the high compression heads does not have more than 8.5:1 from the factory and most truck engines are absolutely terrible in that department, but I really can't suggest how and why each component contributed or exactly which parts you will need for economy.
I don't know much about truck FEs, but I bet if you look at the way it's assembled from the factory, you can increase the compression by minimum of a full point and still be able to run just fine on regular. I'm talking about the actual compression, not what they advertised - you can throw that out the window. Can anyone who knows about FEs comment on this?
