Inlet Manifold Advice

["Harris, Bob G." <R.G.Harris@domain.elided>]

Dear All,

I need your advice on working on the inlet manifold.

I've taken it off (very early Mk2) to solve a small but annoying coolant 
leak into the vee.  It appears to have been caused by a gasket failure on 
the right hand head, on the furthest forward face, right at the top.  There 
appears to be a small water channel (1/4" dia) at that point.  Some clown 
has gouged the head close to that point in the past and that may well have 
been the reason for the failure.

I also discover 4 or 5 of the bolts have got stripped, or near stripped, 
threads, and I am now waiting for a helicoiling kit to arrive to deal with 
that which leads to the questions:

1 what is the best way to drill out the holes?  I have concerns about using 
a power drill - it is too easy to do a lot of damage with one!  Is a better 
approach to use some sort of hand tool?

2 Is there a suitable cutting fluid for use on aluminium - I use ordinary 
oil on ferrous but have no idea for this


Gaskets:
Previous discussions on gaskets etc have said get everything true and flat 
and then use a smear of grease before refitting.  Since I have some small 
gouges in the head mating surface, what is the wisdom about putting a very 
small amount of gasket sealant on the gouge to act as a sort of filler and 
improve mating?  I would only put this on the gouged bit and grease the 
rest.

Also one of the heads has had corrosion in the past and the surface is a 
bit pitted - is this likely to be a problem, or will the gasket cope?


Thanks and have a Merry Christmas

Bob Harris