header question
 

Do aftermarket headers actually give the 911 motor any extra HP? Anyone run headers and then early stock exchangers and see any difference? I am curious about this as the stock design is pretty good in my opinion.

It depends.....

It depends on what?

If you are comparing early heat exchangers to headers of the same tubing size and length, I doubt there would be any improvement in power.

If you start changing engine parameters and or mufflers then headers of different tubing size or length could be an improvement.

Lots of variables to consider.

Thanks for the imfo.

also depends on what car you have, which you do not mention. that might be a good jump off point.

I have a 2.7 RS spec motor with weber IDA carbs, webb cams, msd, pertronics, msd coil, early ssi exchangers, M&K 2 in 2 out. I don't mind loosing my heat in the cabin but if no hp gain with same size tube stainless headers I will just keep my $.

Sounds like a nice motor. You will gain a little power if the diameter of the individual pipes is larger, but that is dependent on your exhaust port size and if it is larger than your current individual pipe. So if you have a 34mm exhaust port and your current manifold has a 34mm pipe, you're not going to gain much of anything going to a 38mm header. With naturally aspirated engines everything has to match for power to be made, there's nothing like them though!

Thank you for the imfo as well. I think that I will just keep what I have. Motor is nice and revs up to 7300 rpm but the throttle shafts are a little worn which I have to get to and it drips a little more oil than I wish it would. It is a bug killer at stop lights.

a set of SSI heat exchangers will continue to suit that jewel properly. equal length, stainless, keep the heat, & a 1.5" I.D. any other choice would be second best.