On the last couple of flights I have been trying airports that do not have SIDS/STARS, so rather than taking off with LNAV armed I am using Heading Select instead. If I arm Heading Select and VNAV then, as I hit TO/GA both modes clear off the MCP and then can't be re-engaged until I am up in the air. Is that correct behaviour, or am I doing something that I shouldn't ?? G

You need to look at the Flight Mode Annunciator on on PFD to see what modes are armed or active. Also, you don't really need to arm HDG SEL on the ground since it defaults to the airborne. When you're ready for T/O, you should have VNAV in small white letters on the PFD.

When I try with both, then they appear on the PFD until TO/GA is pressed, then they clear off. Will try with just VNAV next time.....Cheers,G

i was wondering the same thing. VNAV seems to come active again once you press CMD but no heading mode is showing.

The default roll mode in TOGA is wings level !! ) you can change this to heading select in the CDU options) If LNAV is not armed on the ground then you must use heading select or LNAV after reaching 400 ft if you want a roll mode active.

I believe with FMC U10.8A, the plane defaults to heading sel on climb-out. Probably around 400'. I could look, but meh. If you arm the LNAV on the ground, it'll be active at 50'. You don't need to arm HDG SEL on the ground.

Wings Level vs. HDG SEL in TO/GA is an airline option, it doesn't have anything to do with FMC version.