All Small Six Outside the box log manifold surgery

[AZragtop]

I recently purchased a’72 ragtop for a friend and shipped it back to him. He and the family are having a great time with the six banger, besides a few minor setbacks.
That said, I’ve become enamored with these little sixes having been brought up on British iron.
The log manifolds are obviously the choke point in these engines. And having researched the ins and outs of dissecting one to increase power, I was wondering if anyone had attempted to make a cut along the length of the log intake itself thereby exposing the intake runners and the interior of the log. The intake runners, ports and log itself could all then be worked.
The trick would be then in getting the two halves back together. But with two machined surfaces for sealing and perhaps some clamps through the webbing area could it be done?
FWIW I’m keeping my eye out for a core head to try it out on.
Forgive me if this seems way out there but there’s not much use in going outside when it’s a hundred and God awful out there.
Thoughts?

 

[drag-200stang]

The late model large logs are not that bad, The castings are thin, not much changing can be done, 90% of flow gains are within 2'' of valve, that can be accessed. The best gains with moderate work is the Tri-power but not the choked down production one where they use a small hole in manifold, it kills the signal to carb. You want to make the hole 1-7/16'' for best performance, to do that the homemade adapter will have to be positioned closer to 2 than 1 and closer to 5 than 6 where there is more room. 1--O-2, 5-O--6, Forget that it is not centered between the cylinders crap, the carb in the middle is not is it. The tri-power makes the log mostly inconsequential. Hood clearance can be a problem sometimes.

 

[AZragtop]

Thanks for the reply. I guess sometimes it’s better to let sleeping logs lie!

The late model large logs are not that bad, The castings are thin, not much changing can be done, 90% of flow gains are within 2'' of valve, that can be accessed. The best gains with moderate work is the Tri-power but not the choked down production one where they use a small hole in manifold, it kills the signal to carb. You want to make the hole 1-7/16'' for best performance, to do that the homemade adapter will have to be positioned closer to 2 than 1 and closer to 5 than 6 where there is more room. 1--O-2, 5-O--6, Forget that it is not centered between the cylinders crap, the carb in the middle is not is it. The tri-power makes the log mostly inconsequential. Hood clearance can be a problem sometimes.

 

[bmbm40]

What vehicle are you discussing?

 

[AZragtop]

What vehicle are you discussing?

Not so much a particular vehicle but rather the log manifold itself.

 

[bmbm40]

Not so much a particular vehicle but rather the log manifold itself.

Got it. Around 1969 Ford started providing the 250 inline for some models like Mustang, Comet, Maverick and others. The heads kept getting better to the end of production in 1983. My point is a well prepared late model large log head on a 250 with a mild cam, 2v carb and compression boost is comparable to a 289. Your goal for more power could also be furthered with the aluminum head, hard to find at this time, or an Australian head which will quickly fix the log head problem.

 

[drag-200stang]

I love the large log ,one less thing to do and all the boost I can give it and no leaks.