Side pipes and headers SPF 351
 

Anyone have suggestions on replacing the headers and side pipes from stock Superformance units? The car feels like it has a head cold. I am running a small block 351/418. Fire Fly is the only option I have seen thus far.

check out stainless headers, Stainless Headers Mfg., Inc. fabricates custom headers in stainless and mild steel tons of options, not sure if they have a bolt in replacement but they certainly have custom capability. they are just in process of building me a set.

Full throttle in Reno will build you a set of sidepipes that will wake up your engine. They can either redo yours or will sell you a set exchange. Put a small mirror into the end of your sidepipes and take a look at how small the muffler really is. My inside diameter was around 1 3/4 inch and my 427 sounded like a sewing machine. Had full throttle make me a set with 3" diameter muffler and now the engine sounds and feels like a top fuel dragster.

Make sure you have the correct headers for your engine. SPF has two different sets for 302/351 blocks. The larger port size is the one that should have been installed from the dealer.

Easy fix and one you will never regret.

We had traction problems after upgrading an SPF exhaust it made that much difference. I have used Stainless Specialties mufflers and usually keep a set of Classic Chambered on the shelf. I'm putting them on a stroked SPF Windsor now coincidentally.
Even comes with destructions!
Classic Chambered Exhaust Inc. - Cobra

Installed larger mufflers into existing side pipes then recoated. You will pick up some HP with that size motor, 10-20?, and will really sound much better. If you go 3 inch muffler you will need earplugs all the time.

I would seriously consider FireFly. I could not be happier with the look, sound, and build quality of the side pipes from Ron Roberts.

+1 for Firefly and Ron Roberts

I agree that if you want a new set of stainless steel pipes, Firefly is the way to go.

However, if you're satisfied with the look and condition of your stock pipes, Full Throttle will open up your existing muffler, to whatever diameter you decide on, and then have them ceramic coated and shipped back to you for about half the cost of a new set from Firefly.

+3 for Ron and Firefly pipes - the way to go!

What is your opinion on size pipes from Ron? He has 2.5" vs 3". Ron said 3" is super loud/race and 2.5" is aggressive and nice sounding. Also, has anyone bought his headers? What is your opinion about the stock SPF headers...worthwhile swapping them?

I know Ron's work personally - great stuff!.

I know many people with his pipes and also have done headers and they are very happy. If you have the cash I would do the headers also.

On size, it is a personal choice based on the sound and sound level you are after. Keep in mind they are at your ear so it will also effect your driving comfort. The 2.5 will sound mean enough (for my taste).

Jeff

Any sound clips?

I believe these are the 2.5" My friend's new Superformance Cobra - YouTube

I believe that 3" mufflers are recommended if you have over 500 hp.

+4 for Ron and Firefly. Purchased early this spring and extremely happy with his pipes. He recommended 2.5 inch mufflers for my 512 hp/522 tq engine.

I'm using a set of polished stainless side pipes from GAS-N. Unfortunately it looks like he may no longer be in the side pipe business, which is unfortunate because the pipes are gorgeous, work, and at around $1500, were a good deal.

I've had three sets of side pipes on my SPF so far: the stock SPF pipes, a set of GAS-N pipes with a 2" core and finally, a set of GAS-N pipes with a 2.5" core. The factory pipes and the 2" core GAS-N pipes were fairly quiet and the GAS-N 2" core pipes had a nice "crackle" to the sound. The 2.5" GAS-N pipes have more of a deep "rumble" to the sound.

I also tested the SPF headers/side pipes and the SPF headers/2" core GAS-N side pipes on the dyno with my 427 SBF. Compared to the stepped 1 5/8" to 1 3/4" dyno headers with no mufflers, what I found, at the 500 HP level, was the factory SPF exhaust system cost something like 20 HP at the peak (5900 RPM). The 2" core GAS-N pipes were right up there with the larger flowpath SPF mufflers. These are the results I saw with my tests. I did not test the 2 1/2" GAS-N pipes on the dyno.

Maybe I got the freak set of factory pipes that don't cost a bunch of power. I doubt it, but if so, I should sell them at a premium price!

Does my car run any better with the larger core mufflers? I can't tell-I seem to have a traction problem with whatever muffler is on the car. I do think the 2 1/2" core pipes are easier on the ears compared to the 2" pipes. I do know that loud does not always equal more power.

Went with the 2.5". Should be here next week. Staying with the stock SPF headers for now. Thanks for the input!

20 HP gain matches up with what others have posted on a 427 SB. On my 351, larger muffler HP gain was almost nils on the dyno. Actually lost some down low.

Stephen @ Full Throttle uses COBRAPACK mufflers. I know.

I installed the 2.5" pipes from Ron at Firefly. The craftsmanship is excellent. The sound is well balanced for street use. Idle is healthy and reminds you what you are about to unleash. On the throttle is loud but exactly what you want and expect. Cruise is down right quiet. Ear plugs are optional! The best part...they make power over the stock Superformance pipes by a big margin. The "head cold" that the car had is now gone. Thanks all for the recommendation.