Hotrod Magazine Slant Six Build Up

[kesteb]

So, here is my big question from that story.
They picked up 16 horsepower going from the stock exhaust manifold, to the cast duals.
But, at the same time, they eliminated the heat source from under the carb.
I know on a 400 horse BB, blocking the heat crossover is worth approximately 25 horsepower.
How much of that gain was due the manifolds and how much to cooling the intake charge?

A better question may be how much power was lost by removing the heat source. Unlike a v8, where the carb sits in the middle of heat source, on a slant, the carb is 4 to 6 inches from the heat source. Especially when you use headers or the dutras. That heat source helps with the fuel distribution, remove it and the fuel/air starts to seperate.

But you know that already...

 

[whitepunkonnitro]

A better question may be how much power was lost by removing the heat source. Unlike a v8, where the carb sits in the middle of heat source, on a slant, the carb is 4 to 6 inches from the heat source. Especially when you use headers or the dutras. That heat source helps with the fuel distribution, remove it and the fuel/air starts to seperate.

But you know that already...

Once up to operating temp, there is more than enough radiant heat from the cylinder head to do the job.
No theory, it's fact. I've run them around that way

 

[kesteb]

So have I, and I disagree.