This Carb spacer didn’t work for me, but might for you

allways a bit of fun with aftermarket parts

Try fitting 3 x 2 barrel webers to a Redline manifold that has the centre carb mounting skewed to the left by 2 degrees. the manifold cost is $999 Australian dollars, you'd think they would get it right....

but no. all of them are like that for no good reason

Hence

A bolt with a smaller head..... that will do it ... :)

Dave
Were they trying to level the carbs? Some V engine manifold carb bases are tilted