Port matching for Weber 45’s

[RoadRace]

I recently got an old-new intake for my race car.

the original one was cast for 40mm carbs and opened for 45’s, breached, welded - it worked but was ugly and potentially leaking, causing the tuning problems i was having.

 

on eBay recently was a period correct SK intake for 44’s, so my Weber 45’s should be dreamy.

 

to start this off, I will try and make it as simple as possible – I have phoenolic  spacers behind the rubber gaskets for the 45 mill carbs, I’m using those for the template.

i made small alum alignment pins to hold the spacer in place, and i scribed the line onto the intake.

i used a tulip shaped carbide burr to get close and shape the transition, the a larger 1” diameter sanding drum to make a smooth radius.

Well, three of the cylinders were perfectly centred and only required opening up, The number one cylinder was offset by almost 2 mm, emphasising the need to verify alignment on Parts like this.