Compression ratio for 6.2 NA

[Stage1]

What are the pro's and con's of compression ratios 20:1 vs 18:1. I read that the 20:1 aids cold weather starting. More interested in power and fuel consumption impacts. Engine is from a 82 to 86 CUCV ( I have a lot of them).
Thoughts on CLEVITE PISTONS, PART NUMBER 9-1467D.0.5. (CURRENT CLEVITE PART NUMBER 224-2185 FOR INDIVIDUAL PISTONS AND TC-2185 FOR THE SET).COMPRESSION RATIO 20:1 w/ FLAT HEAD WITH RICARDO CUP.

I have no plans to add turbo. Main interest is milage in a blazer.

[britannic]

IMHO, stay with the higher compression ratio for better efficiency, unless you intend hot-rodding the engine (19:1 works well with a "steenking turbo" and intercooler combo :D ).

[Stage1]

Britannic,

Thanks, any thoughts/experience w/ the pistons mentioned above?

Also, I had a question about 6.2 CUCV engine block Ni content, you wrote about a while back.

thanks,
Les

[john8662]

Stock C/R is the way to go with a Naturally Aspirated (non turbo) engine.

The stock compression ratio is 21.5 to 1

To get a 20.5 to 1, you use the .010 topped pistons (normally used for engines that required decking during rebuilding)

To get 19.5 to 1. you would be using the topped pistons, and then taking another .010 off the tops.

The stock compression ratio pistons will give you better fuel economy, because of the more complete burn, they will also aide in starting.

[Stage1]

John,
Thanks, do you know anything about the pistons listed in my origional post?