Duals....X pipe vs H pipe

[el corvino]

H pipes do not flow as well... it's simple science that an X-Pipe would flow easier. H pipes have always been known for the simplicity of the install, with the exception of a turbo car. X-pipes having a higher pitch? My 550 HP flowing through 3" X-pipes don't sound like a little girl screaming. Not sure of this high pitch nonsense. You want to adjust the way it sounds, go straight pipes or decide on a desired set of mufflers.

 

[olds307 and 403]

I have used the Summit H pipe kit, it worked decent. I added it to boost torque and quite my exhaust on my old 78 1/2 ton with an Olds 307, then an Olds 350. Man is an unpadded interior louder, the H pipe helped a little but I still needed a second set of turbo mufflers behind the glass packs to make it tolerable to drive. I assume you have a dual hump crossmember picked out? It was tight on my car with the shorty headers and 2.5" pipe going under the single hump. Another thing is you will have to run the 307 size oil filter with nearly any headers, the Mobil One filter is shorter than the Amsoil and Wix filter. I would look into a mini starter, the 307 starter is wimpy, not good enough when hot to crank that high compression 350. You can get the Olds specific starter but believe it or not the sbc straight bolt pattern mini starters bolt on and work fine. I bought the Summit 829100 copy of the Power master 9100, what a POS. Never worked right from day one but it sat in a box for months, by the time it completely stopped working, no warranty. The Power master was great for $10 more. The Olds/Pontiac Summit mini starter is also good as long as you don't over tighten the connection that says don't over tighten this connection. First one I got didn't have that, ask me how I know.

 

[SupremeSpeed]

Thanks fo

I have used the Summit H pipe kit, it worked decent. I added it to boost torque and quite my exhaust on my old 78 1/2 ton with an Olds 307, then an Olds 350. Man is an unpadded interior louder, the H pipe helped a little but I still needed a second set of turbo mufflers behind the glass packs to make it tolerable to drive. I assume you have a dual hump crossmember picked out? It was tight on my car with the shorty headers and 2.5" pipe going under the single hump. Another thing is you will have to run the 307 size oil filter with nearly any headers, the Mobil One filter is shorter than the Amsoil and Wix filter. I would look into a mini starter, the 307 starter is wimpy, not good enough when hot to crank that high compression 350. You can get the Olds specific starter but believe it or not the sbc straight bolt pattern mini starters bolt on and work fine. I bought the Summit 829100 copy of the Power master 9100, what a POS. Never worked right from day one but it sat in a box for months, by the time it completely stopped working, no warranty. The Power master was great for $10 more. The Olds/Pontiac Summit mini starter is also good as long as you don't over tighten the connection that says don't over tighten this connection. First one I got didn't have that, ask me how I know.

Very helpful! As a matter of fact, I do have one picked a double hump crossmember picked out. I'm looking at the G- Force crossmember from Summit. The idea of a performance starter did cross my mind, however I wasn't sure if I actually needed one. Thanks for that advice as well.

 

[quicksabre]

I've tried them all to the point of making flanged sections so that I could switch between H, X and nothing at the track. Keep in mind this is with Flowmasters which theoretically conflict with the principal of what an X does.

H did nothing but make the sound more mellow. X took exactly from the top end what it gave to 60 and 330'. No change to 1/4mile ET. So I took all of it off and have 3.5" collectors reduced to 3" exhaust. Either, especially the X, takes away from the stereo type sound of duals. So because I like that sound and because I lost MPH I run without either one.

 

[jlcustomz]

X vs h pipe is a lengthy discussion on many forums over the years . I firmly believe x-pipe gives a small performance margin,,,,which most would never be able to feel the difference.
I personally switched from h to x on the same everything else. Results vary per application & in my case less drone & the more raspy sound is ok with my LS1.
BOTH crossover types allow both cylinder banks to breathe through both mufflers, so either is better performance wise than none. X-pipe actually scavenges, which can take different tuning to fully benefit from.

Some high tech systems use both types together. .
A recent vette system uses 2 x-pipes

 

[Mr.hustlehard]

Have no complaints about the system but there wasn't any performance gains for me from duals.

View attachment 55303

Does your engine have any modifications? Even if your engine is pure stock, you would still have a performance gain, though very little. To feel anyway.

 

[SoFloG]

Just throwing this out there. .. what about neither? Just saying I have straight 3" all the way back with ball flanges on collectors. My exhaust guy said it wasn't worth the hassle to worry about h or x pipe and that there aren't any real gains if your pipe diameter is large enough to begin with.

 

[lilbowtie]

Does your engine have any modifications? Even if your engine is pure stock, you would still have a performance gain, though very little. To feel anyway.

Short block is a stock 350 ( L-82) good set of iron 2.02 heads w/ comps flat tappet solid cam w/ a Vic Jr and a 750. Car runs 11:20's and didn't see any gain.