Does anyone know how think the steel used to make the the steel sump is on a black top engine? As I don't want to pull my sump off until I have the steel to modify it

Thanks

I would say 18swg but you may find it ok to use 16swg. Make sure you bolt it down well or it may distort badly. An old block is ideal but a thick plate may suffice.

About 1mm
Heres the link to modding minem towards the end of the thread

http://www.locostbuilders.co.uk/viewthread.php?tid=149348

Remember the 'gasket' is not separate but bonded to the steel. Can't buy a new one so separate the steel from the ally carefully and use goo when you bolt up.