what length helicoil for stripped valve cover holes, 78 g5

[amamet]

i have a bout 5 stripped valve cover holes in the heads of my 78 g5 that I'm finally going to address.  (got it this way).  i have the heads removed and was wondering what length i should order.  local shop asked me, 6mm x ?
thx
allen

[Tom]

This is a lousy answer.  I used what matched up to the bolts or close to it.  I got a Heli-coil kit from NAPA and used it on my LM III. 

[flangeman_70]

6x10mm is good.
Iv'e done all mine on my SPIII

Adam

[Wayne Orwig]

I bought a kit from NAPA, # 770-3091. There is no mention of length. It is of course a M6x1 and needs a 0.250 inch drill bit.
The package with the HeliCoils themselves, inside the kit, is labeled M6x1 9.0 length.
I have used those on a number of valve covers and sumps. A little longer would not be a problem.

[amamet]

should i be getting the self locking helicoil?  what locks the standard helical in place and keeps it from coming out upon disassembly?   sorry, never used them before
thx
allen

[twhitaker]

In its free state, the helicoil is a bit larger in diameter than the hole. Once threaded in, that 'spring force' holds it in place.