just received my helicoil kit to repair headbolt threads in my b20 block, the helicoil seems pretty short IMHO, is only one of those really strong enough to hold on?

(i know timesert would be better but Im having a pretty hard time finding a kit here in Canada...)

thanks

 

If it's installed corectly then it should be fine.I've used them for main bolt holes,rocker arm,head studs,etc... before without any trouble.