A HIF 6 mixture screw screws counterclockwise to make it leaner and clockwise to richen it, totally opposite of most carbs.

Entire car was redone top to bottom.  I know there is a breather hose on the gas tank, but have not checked if its cracked.

With regards to gas type/brand, the tank has been filled multiple times, no difference in smell.

As for rich lesn, I have checked the plugs and they seem to have a light brown color to them, which maybe a little on the rich side, but not abnormal.  

Anyone know which way the mixture screw on a HIF6 carb needs to be turned to make leaner?  I know where the screw is, just not sure which way to go.

Btw:  I have one engine steady on, motor still torques quite a bit.  Because I am also getting some vibrations in the body, want to install the flex pipe before I reinstall the second steady.

If you armor sprayed the bottom, could the hot exhaust be heating and possibly melting/burning the armor?

your mini maybe running to rich, you may want to revisit your carb tunning. 

tried a different gas station? They are all not alike.

Sulfur in the fuel is a big problem. Some really stink, even before burned

I just had a thought, are you sure it's exhaust you smell and not raw gas? Check the fuel tank breather pipe has not dropped off or that you even have one fitted? It's a hard plastic pipe from the top of the tank which goes down through the trunk floor.

The engine steady should keep everything in place. If you think there is an exhaust leak at the engine the header flange may be warped or a failed gasket. I have seen new LCB's out of the box with warped head flange/face that required a resurfacing to seal properly.

Smell only when Windows open.  The entire car has been dyno matted and armor sprayed from the bottom.  

It's a low pressure in cabin problem when Windows opened.

As for the carb, I get a nice clean burn on the plugs and motor runs/ pulls strong, I suspect mixture is on point.

You need to find the source of your smell! Adding a cat will not solve it in fact it may well make it worse. Instead of exhaust gases you will get rotten eggs from the sulphide caused by the uncontrolled carburetor. 
1st make sure you have no open holes in the floor or bulkheads to allow fumes inside car. Make sure the tailpipe is beyond the bumper not before or right under it. 

1962 MK1 with 1380 hot motor running the headers and rc40 exhaust, with side exit just past the left side of the rear bumper.  The header/exhaust flange pieces have all been welded together, so no clamped pieces to leak.  All glass and trunk seals are new.

Wondering two things:

1) I just purchased one of these and will add to exhaust as I suspect the header flange may leak between the gasket and head when the motor flexes with the torque of the 1380.  

//www.ebay.com/itm/Exhaust-Flex-Pipe-Stainless-Steel-Double-Braid-1-75-x-6-OAL-17506D-/171197693500?hash=item27dc2d7e3c:gHQAAOSw5dNWqqU8&vxp=mtr

2) Wondering if the addition of a high flow cat will eliminate the exhaust smell problem.  Has any one tried this with success?  Do the MPI's have any similar problem?

//www.ebay.com/itm/1-75-Thunderbolt-Catalytic-Converter-High-Flow-Stainless-Steel-/140941752289?hash=item20d0c877e1:g:NrMAAOSw8cNUSQa5&vxp=mtr

I need the exhaust smell gone so I can enjoy the mini with wife and kids, neither of whom will ride in it because of the smell.