thanks ron for your instructions on posting photos, here goes,
above: this is where i have replaced the original steel bleed pipe with a larger 3/8" OD stainless tube threaded 1/8" BSP (a 3/8" OD pipe will accept a 1/8 BSP pipe thread) and drilled and tapped likewise in the old hole, to aid the flow and prevent blocking up with sediment (refered to as crud as in previous posts) The extra hole you can see midway down (also drilled and tapped 1/8"BSP was to enable poking in with a piece of tiewire to loosen and flush out more crud and there was a lot of it. This hole will be plugged up.
above: looking at the rear of the carby block I again drilled (and tapped 1/8"BSP) a hole to help loosen and clear to flush out more crud, and through this hole poke in some wire to locate the feed hole and make sure it was clear into the main water jacket (for info I drill a small pilot hole then the 17/32" tapping drill for 1/8"BSP thread) and as you can see I will fit a larger tube and feed this from a point at the rear blanked off port. The theory being is that water into here will flow out the bleed pipe and the small (3/16") feed hole as well keeping it clear of crud, and probably helping to heat up better this part of the carby block.
above: this is looking into the cavity after I removed the welch plug on my spare manifold and down in the dark part is where the feed hole is which would be impossible to reach from the bleed hole itself without drilling the extra one as in the previous pic, as there would be no other way of clearing/checking this hole unless you removed the welch plug underneath the manifold.
above: as you can see after removing the welch plug underneath you can find the 3/16" hole which feeds up into the carby block and on this my spare was comletely blocked solid and was not noticable at first glance until I noticed a slight dimple then poked it clear with a small screwdriver.
above: this is the blanked off part at the rear of the manifold which I have drilled and tapped 1/4"BSP to take a 1/4-1/8 BSP reducer then fit a 3/8 (threaded 1/8BSP) pipe from here to the back of the carby block to improve the flow, better heat this part of the manifold and help keep this cavity from filling up with sediment, any thoughts and comments are most welcome.
above: oh and this is my rover before I started work on it. the original green was Arden and last owner gave it a respray in what looks like British Racing Green, which I must say looks very nice as you can see the original darker Arden green inside the door opening