http://www.ebay.com/itm/NOS-NEW-OEM-FORD-E100-E200-E300-F100-F250-F350-EXHAUST-MANIFOLD-1965-1974-/281531355270?pt=Motors_Car_Truck_Parts_Accessories&hash=item418c939086&vxp=mtr

 

for 500 bucks?!? wow...must have pixiedust and unicorn tears cast into it or something. efi manifolds get my vote any day of the week.

 

The F600 manifold flows a little better than the EFI mannies do. You can buy new reproductions for $200.

 

I can see how it may flow a bit better. I'd be really interested to see any flow numbers, dyno charts, etc. that could show the real differences between the efi manifolds, different headers, HD manifold, and stock log setup...
Any references for the $200 HD deal? particular business or link?

 

How do you know that?

 

Well I don't know per se but that's what I've read a bit online. What I do know though is that it has a 2.5" outlet versus the 2" outlets of the EFIs. It's probably such a small difference that you'd never notice.

 

I guess if you read it online it must be true.

 

Well I can't exactly argue your thought process there...

 

HD Exhaust
2.5" = 4.9 square inches.

I *think* the EFI manifolds are 1.75" each.
1.75" = 2.4 square inches each.
x2 = 4.8 square inches.

Not a lot of difference.


However, from what I understand, the EFI manifolds have an advantage from the fact that, due to the firing order, the engine is always firing into an empty manifold (ie. it never fires into the same exhaust manifold twice in a row). Since it's empty, it creates a vacuum effect that helps to pull the exhaust out of the engine, for a little added benefit.
How much truth there is to that... Dunno. Makes sense to me though.

Both are cool in their own way though, and the HD setup has the added bonus of being awesome for a turbo setup.