Honed manifolds.....

Has anyone had any experience with extrude honed manifolds? If so, how did they flow vs headers, and were they any less durable. Thinking about a few things, and it is a question I want to find an answer to. Thanks in advance,

 

At one time it was the thing to do. I would imagine it makes a difference. I'll have to dig out my copies of "Super Ford" and see what they say.

 

I remember reading about it....'Bout the same time i was buying a pager

 

You won't get manifolds to flow anywhere close to long tube headers, probably not even into shorty header range. Now maybe if you started with HiPo manifolds you might get close to shorty headers.

 

There's bound to be some info out there. Id say there's quite a few f.a.s.t. drag guys doing it.

 

Most of what I've seen, was they did the intake.

 

Thanks guys. I was just thinking about ground clearance and working room in the engine compartment. Might be too expensive to do, but thought I would ask.

 

I looked into it for my orange car. After all the research, decided it best to get the Doug Thorley shorties.

 

Craig; I think I will stay with my FlowTech long tubes. They seem to work, and I checked them the other day and after 11yrs, no rust holes or leaks.

 

Biggest flow gains on manifolds will be from actual hand porting then having them Extrude Honed. Still not a good as long tubes. Depending on the original design we have seen flow increases of about 15-20%. Good for stock-appearing classes or just trying to be sneaky. It is expensive though.

 

Yeah, I have inquired into a few places, and they want $400-600 for a pair of stockers, and they won't flow test them for that. Looks like I'll keep the long tubes.

 

I'm firmly convinced that this process is best reserved for things OTHER than automotive stuff. It is just too cost prohibitive. I ported a set of exhaust manifolds for a F.A.S.T. competitor with a 429CJ Mustang. Once I had them ported he had them extrude honed in several steps that he specified to them. Flow increased 35% but it cost him over $1200 in honing alone. Long tubes are dirt cheap by comparison.