If I port my MAC headers and put regular header flanges on them instead of ball flanges, how much horsepower will I pick up?

 

I know a few people on here have done this. I just want to know if its worth the trouble of doing it.

 

It would be a better improvment to put the L/T's on it.

 

Ditto Wrencher, would be more practical going to LT's but I could see you gaining 3-4 more RWHP by fully porting them, you would have to get them recoated because you would murder the coating during the porting. Good Luck man

WeS

 

Not what I asked. If your trying to sell me on getting L/T's, your wasting your time.

 

Ive searched this topic in the past and never found an answer. Portin the primarys are worthwhile. Its easy and free at least. Its hard to if say removin the ball flange is worth the money. The same for flowmaster collector mod on the ypipe. I did the mod on the ypipe but held off on removin the ball flanges. I figured after the added costs to remove the ball flanges might as well get some long tubes.

For what its worth theres a guy runnin 10.60 with a h/c 346 with macs and ory. Cant remember if he did anything to the headers and y.

 

I answered your ? later on in the reply, Wyhy are you so sold on getting macs, they are great headers and all and you will see a good gain from stock but they dont offer the power of LT's. Whatever you do man good luck

WeS

 

Oops you were talking about Wrenchers post, my bad man.

 

i have macs, and dont feel like dropping money on LT's so im in the same boat

i havent ported the primaries on mine because im too lazy to pull the headers outta my car, but iam getting a custom exhuast setup in a few weeks and will be modding them in the following manner

-cut off ball flanges (just looking at them you can tell they hinder flow)
-extending collectors about 8"
-adding 3" 3bolt collectors
-custom 3" yipe with dual cutouts
-flowmaster 3x3x3.5" ycollector

rest of exhuast will be 3.5" pipe with a flowmaster delta FORCE muffler dumped under the car

with my h/c setup i know the ballflanges, 2.5" ypipe and crappy 2.5" collector are killing flow

if i ever have the headers off ill port the primaries

 

Hey Dug, haven't seen you on here in awhile. How's the car runnin'?

Tally, I'm doing the came thing except no extended collectors or dual cuts. I'm going from the ORY to a 3.5" I-pipe with a bullet and turndown before the axle.

Sorry guys, I just hate LT's. I've got a few friends going alot faster than alot of people on the this board with MAC's. They've just proven themselves to me from what I've seen.

 

Tally and PTM, that exhaust set up is gonna be sweet. Do you think its possible to keep the pipes before the y equal length. I was reading at DR.Gas website about ypipes, and it said keeping them equal length is best for sound and power. It got me thinking that this might be where the rasp comes from on these cars. None of the ory's are anything close to being equal length.

PTM, the car is runnin great after cam and headers. Needs tuning though. I hear you about header prices. What sealed the deal for me was the weight savings over cast iron exhaust manifolds. Icing on the cake.

 

it would be damn hard to make the pipes equal length since the ipipe runs down the passenger side of the car. im fairly certain that the rasp comes from the ballflanges and the y collector design

well know in about a month though

 

those ballflanges are quite bothersome
i should have cut mine off the first time around

 

I ported my Macs in each head port, collector and ball flanges. I ground out the weld build up in the head ports and collector. I opened the inside diameter of each ball to equal or greater than the ID of the 2 1/2" Y pipe. I also installed a Flowmaster dual 2 1/2" x 3 1/2" collector.

Mine seems to run pretty good. Would be interesting to see if long tubes would make a difference.