The Special Wagon needs a little attention power wise. I have an engine with edelbrock heads I’d like to install. Sure headers would be fun but they don’t fit too well - at least the ones I tried 25 years ago. So, has this been done…nice Gessler ported manifolds. Engine was in a 69 Special that went about 11 seconds in the qtr.
We recently did a exhaust comparison dyno test on a 450hp street motor with al. heads that just had a cleanup port. We tried stock iron manifolds, then ported iron manifolds, then headers. Found 15 - 18 hp with ported iron over stock iron, then another 20 hp with the headers.
At least two of your BSA competitors were running aluminum heads. Ported manifolds would help, too. Patrick
You can run shorty headers - won´t loose much compared to long tube, but don´t hassle with that motor swap, I´ll take the wagon with the old motor, LOL.
I would like to see you use a header gasket between the cast iron manifold and the alum head. Galvanic corrosion can be an issue, due to the dissimilar metals. The use of a good gasket, like the Remflex, will allow the manifold to move around like on the alum head like it's going to .. Manifolds have to be allowed to move in relation to the head.. or they crack.. that's why the factory used ramp loc bolts and 18 ft lbs torque. Now enter alum heads, those manifolds are going to be moving a bunch.. would not want them directly bolted to the head, with no gaskets.. JW