I wonder since the issue of a Header is for improved volumetric efficiency ( on a stock engine internally) and possibly better fuel economy is relevant, given the space restrictions and cooking the Battery in its stock location. My (currently unavailable Hooker Super Comp 4-1) header didn't work well with a stock intake and engine Until I installed the Weber 38 DGAS non progressive 2 bbl carb. Then the extra fuel and punch down low really woke up the torque delivery.
Look at the Pinto 2.0L Headers in Burton Power's web site (Simpson) and you can see why tubular headers have limited usage on street cars and the Pinto is a tight fit for even those with modifications to motor mounts. A rally engine is too hot to pass a smog test and these headers are off road usage primarily.
So find a UK SOHC 2.0L cast iron manifold and then pat yourself on the back
There's a UK member on this site with a 73 wagon that's gone through this with his "Donkey"
Enjoy all the Fun, it's like archeology
Pintosopher, Never hoping to come up "lame"