In the 60's and early 70's, one easy, cheap way for auto companies and private car owners to get more power was to install higher compression pistons. That was possible because the gas was of better quality with higher octane and with lead as an anti-knock compound and lubricant.
Then, in about '73, the government regulations and stiffer insurance standards as well and gas quality dropping led to lower horsepower in cars. Plus, in the early 80's, lead was removed from gas.
So I've read many car magazines where they stated that the simple plan of raising compression is now out(since the 70's and 80's), and if you want to increase engine power, you must do it while maintaining about an 8.5:1 to 9:1 compression ratio. So you had to get your power another way, such as improving cylinder head flow, better cam, power adders, etc.
But if you still owned an older high compression engine, you HAD TO use premium fuel with an octane booster, or racing fuel, and maybe even a bottled lead additive as well. So that deterred most from high compression engines.
According to every magazine I read, you didnt want to exceed about 9:1 or maybe 9.5: at the most. although they even recommended against that. The reason was that you'd likely have detonation problems in the engine, and it would ruin it. I never heard anyone recommending 11:1 or anything higher, unless it was a race car using race fuel! :nono:
But now, I'm reading how newer American engines have 11:1 compression! I certainly have not noticed that gas quality or octane ratings have gotten better or gone up, so how are they able to get away with these high compression ratios without problems like detonation?
Then, in about '73, the government regulations and stiffer insurance standards as well and gas quality dropping led to lower horsepower in cars. Plus, in the early 80's, lead was removed from gas.
So I've read many car magazines where they stated that the simple plan of raising compression is now out(since the 70's and 80's), and if you want to increase engine power, you must do it while maintaining about an 8.5:1 to 9:1 compression ratio. So you had to get your power another way, such as improving cylinder head flow, better cam, power adders, etc.
But if you still owned an older high compression engine, you HAD TO use premium fuel with an octane booster, or racing fuel, and maybe even a bottled lead additive as well. So that deterred most from high compression engines.
According to every magazine I read, you didnt want to exceed about 9:1 or maybe 9.5: at the most. although they even recommended against that. The reason was that you'd likely have detonation problems in the engine, and it would ruin it. I never heard anyone recommending 11:1 or anything higher, unless it was a race car using race fuel! :nono:
But now, I'm reading how newer American engines have 11:1 compression! I certainly have not noticed that gas quality or octane ratings have gotten better or gone up, so how are they able to get away with these high compression ratios without problems like detonation?
but regardless,, I think a fuel injection update would be a worth while investment, 
