I'm seriously considering putting 243 heads on my 6.0 turning it into an iron LS2. Should be around 11:1 compression. The only reason I haven't done this so far is that in the summer's I tow and go camping out in the boonines - no good gas. I was thinking to have a pcm with a 93 tune and then have another one I can swap in to run 87 on the occasions that I go camping. Will the motor be okay on 87 with lowered timing? I know it will be down on power, but I dont care. I've read that the TBSS runs just fine on 87. Thanks!

 

Can anyone confirm or deny that the 243 heads on the newer 4.8 and 5.3 use 2"/1.55" valves?

 

low octane fuel and high compression = knock, ping, detonation, power loss, and less efficiency...

Instead of having 2 PCMs, you'd be better off just putting 87 in it if you had to(with the 93 tune). The detonation/knock created by the lower octane fuel will cause the PCM to retard timing, which will roll it into the low octane tables anyway.....

 

I guess I'll have to ask Charlie about this.

If the TBSS can run just fine on 87 I see no reason why I couldn't.

 

Here's the advice I got from Predator-Z


8.47 DCR which is fine on 11.0:1 SCR
My advice is to run 1 step colder plugs like TR6 gapped at .040>.045 (they come .035 from factory)
The colder plug will reduce chances of detonation.