Best 2V exhaust manifolds?

[mcgr]

I've been very fascinated with 96blak54-s NPI and PI camshaft specs topic. I would like to throw another Ford parts bin related question. 2-valve has been fitted to many different vehicles and I have found that there is at least 10 different designs of exhaust manifolds for them.

So here is my question - which one could the best flowing manifold? Could it be fitted to SN95? There is not very much real estate there but maybe it could be done. Has anyone tried? Tubular shorty manifolds are nice but they have their own problems.

03-04 Expedition / 04-06 F-150 RH manifold has quite generous runner bends. DORMAN 674690 for example. And its not much different from Mustang one.
03-04 Expedition / 04-06 F-150 LH manifold seems also quite good design but in SN95 could get tricky with steering shaft. DORMAN 674705 for example.

 

[96blak54]

20 horsepower

naturally aspirated or forced induced

20 horsepower

Over the years and the dyno tests with and without long tubes, shortys, and stock logs.....long tubes offer a 20hp improvement, forced induced and not forced induced all ive ever seen was 20hp. And thats not to say your experiments and knowledge would be void, because doing something different is how we find them tiny bits of improvements. For those who say "that wont work" or "No performance" are the ones with the cookie cutter hp.

With a forced induced scenario, 20hp is not that big of a deal, but for a naturally aspirated engine 20hp is a big deal. What alot of folks dont interpet from improving the atmosphere beyond the exhaust valve is how the cylinder decompresses. The free flowing, non restricted, deviation from stock log, new open atmosphere AKA long tube headers and big exhaust changes how the cylinder decompresses and the nonrestricted atmosphere no longer offer residual blowdown pressure within the cylinder as the piston reaches BDC. Basically shifts the blowdown characteristics to a higher rpm. Decompression blowdown meaning residual exhaust pressure on the piston as the exhaust leaves the cylinder.

If you feel inclined to do the math of piston location relative to crank angle and ex valve open/close sequence, youll discover that the blowdown piston location to crank angle is a wagon train across the plains SLOW, allowing mass amount of time for exhaust release,blowdown, and ample amounts of open time of non-pumping losses with piston ABDC.

 

[mcgr]

N/A build so 20hp gain is nothing to sneeze at! Just trying to find ways to save some bucks and getting some decent power from 98 npi engine. Forced induction is out of the question, I cant make it legal here in Europe. Maybe a hidden nitrous system at best.

 

[96blak54]

Shorty headers do uncork from the stock logs and are far easier to install over the long tubes. Best part is they bolt onto the stock exhaust.

The pi intake, the pi cams, and the pi lash adjusters on the intake valves would be your biggest bang for the buck.Be sure to look for the mustang specific pi cams.