Extrude honing?

[Bad Byrd]

So I am a mod motor guy, thats where most of my experience in performance comes from. In that world of performance I found that extruding honing the upper and lower intake as well as the intake runners on the heads in force induction motor brought a great advantage................has anyone seen or done any extrude honing on these old motors and was there any gains?

[jayb]

I know one guy who extrude-honed a set of 428CJ exhaust manifolds.  I believe he said that there was a small improvement, but that headers still picked the engine up way more.  I don't know of anyone who has extrude honed an FE intake or set of heads.

[Bad Byrd]

I can see where extrude honing really wouldn't be a viable option for exhaust, but in a force induction mod motor the air inlet to the blower as well as the lower intake netter a lower discharge temp  into the cylinder which allowed some additional timing and air flow along with more fuel which netter a big gain of 50 RWHP. Obviously with a N/A vehicle the gains are going to be minimal in comparison but with this old Technology I would think some flow might be gained. Probably not a wise investment but its a thought anyways.

[Joe-jdc]

I have had experience with extrude honed intakes, FE, Y-block, EFI, and I can tell you that extrude honing only increases each ports flow in proportion.  It does nothing to balance the flow between runners.  The good get better, but the bad only get better in relation to the before ratio.
For extrude honing to be best, a manifold should be gasket matched, working up in the runners at least 3 inches, and any plenum work accomplished before sending the manifold out to be extrude honed.  The honing process will smooth out curves somewhat, and give a smoother finish to the runners, and in the process increase airflow.  On the EFI plenums it only works as well as the person who set up the equipment, and for how long they let the putty go through the runners.  It is expensive.  If I tried to charge as much for a balanced porting of a manifold as the extrude hone costs, I would never get a job.  I have flowed several, and my porting gives more airflow, and I try to at least balance the runners to within a percentage of flow.  Joe-JDC

[Bad Byrd]

I agree Joe

The Mod motor stuff I have done all have been hand ported and then extrude honed, however like I stated above where it truly came into play for me was the actual reduction in AIT1 and AIT2 temps. because of the reduction in drag there was enough difference to actually increase the Boost and add additional fuel to obtain more HP. I am not by any means thinking this is a replacement for a good port job, just curious if it had been done around here and where there any gains at all.