Porting an HP exhaust manifold?

[robinsonwr]

I have a set of 68 HP manifolds that I would like to port. I looked out on the net and saw where guys were doing this service. I read and found out that most stage 1 jobs are nothing more than opening up the exhaust ports and modifying the flange for 2 1/2 or 3" exhaust head pipe. Has anyone done this on their own and been successfull? If so can you tell me how to do the head pipe flange? I am pretty sure I can get this done with a little information and save 4 bills plus shipping. Thanks in advance for your comments and instruction.

 

[robinsonwr]

OK, just got off the phone with TTI getting the part number for the head pipe flange they use on their 2.5" and 3" head pipes for manifolds. The part number is FLG-EP250 for both 2.5" and 3" sizes. Yep, same part number they cost $12-13 dollars a piece. So once this comes in I can bolt to manifold scribe and burr it out. Am I on the right track so far? Now I will start looking for nice size exhaust header gasket set for the head side. Cookin with oil now!!!!

 

[bigmanjbmopar]

Interesting, I wouldn't have thought about porting the manifolds. I have a set with broken heat valve on it.

Put up some picks when you get it together.

 

[robinsonwr]

Interesting, I wouldn't have thought about porting the manifolds. I have a set with broken heat valve on it.

Put up some picks when you get it together.

Absolutely will. Did you port the exhaust ports on your Stealth heads for your new motor? If so what gasket part number did you use?

 

[Budnicks]

Really all you need to do is gasket match the manifolds to the heads & blend in 1"-1-1/2" in for a smooth transition & remove only casting flash & sharp edges, radius any entrance or exit holes, your really not going to pick up much flow &/or hp/tq, but it couldn't/won't hurt to clean them up....

 

[62MAX]

Really all you need to do is gasket match the manifolds to the heads & blend in 1"-1-1/2" in for a smooth transition & remove only casting flash & sharp edges, radius any entrance or exit holes, your really not going to pick up much flow &/or hp/tq, but it couldn't/won't hurt to clean them up....

Absolutely right,this has been discussed at length on other boards,results are negligable,two to three hp at best,not worth the cost.Clean them up yourself as best you can and save your money.

 

[lewtot184]

i think doing the extrudahone is only worth a few hp.

 

[HEMI-ITIS]

This really depends on what your goals are with this combo.All these little modifications can add up.I have hung out with some of the guys that run F.A.S.T and SUPERCAR series drag racing.You can be sure the intake & exhaust manifolds have been "massaged":glasses8:

 

[robinsonwr]

Hemi-Itis,
You are correct about the FAST guys and their modifications. I would love to extrude hone my manifolds for peek performance. I would definately buy headers before going to that expense. I just want to "sleep" my 66 with a 600 horse 440/512. Of course there will be a significant loss in power because of running manifolds but it is a dedicated street car.