HO vs SO pistons: Only higher compression?

Topic: HO vs SO pistons: Only higher compression? (Read 1125 times) previous topic - next topic

Along with being forged and is that it?
Just gathering a bit more information.

both are 9:1. SO's are dished and take up the same overall volume as the two reliefs in the HO's

Sweet, thanks man, no need to step up to HO pistons then :hick:

The '86 HO has flat top pistons, with no valve relifs...

I found the specs for the SO to be between 8.4:1 and 8.7:1.

yes, with only a HO cam, you should be ok. anything bigger or better then a stock HO setup is when youll need valve reliefs

Quote from: 88XR7;189071

Sweet, thanks man, no need to step up to HO pistons then :hick:

Unless you want to run a big valve head and a bigger than stock HO cam (like me

)

Quote from: Sick88Tbird;189074

I found the specs for the SO to be between 8.4:1 and 8.7:1.

83-85's were 8.4, when they went to sefi in 86, compression was raised to 8.9

On the E7 pistons the eyebrow valve reliefs are -5.5 cc
Just some info don’t know if it helps.

Quote from: grutinator;189098

83-85's were 8.4, when they went to sefi in 86, compression was raised to 8.9

That explains my malfunction.