rpm wrote:

So...I really gots to axe, are you fellas serious about running straight pipes?

Well..... I saw 6sal6's car at the Franklin TN Bash, and the Vandalia, IL  Bash.  It arrived with mufflers attached, but as soon as they cooled off, Sal was under there making the adjustment to his personal preference of "sans muffs".

I hope DC can make the 2019 Bash in Michigan.  Perhaps we can verify muffler status, there...

DC wrote:

I just can't imagine any good reason to put mufflers on Long Tubes!

Yeaaaaaaaaaaaaaaaaaaaaaaaaaaah!!! My Man!!
6sal6
 

I learned recently that most folks perception of long tubes only being good for high end is not at all true. I have played with the tuning and now have great torque throughout the revs. I got to thinking that modern ignition and fuel injection can make about anything work better. By playing with all aspects of the carb and teaching the driver how to apply throttle with the correct ignition curve we are very close to a full power curve. I would like to try a variable volume collector on a set of long tubes but the rule book won't allow. I was reading some stuff that was done to the throttle curve and thought what is that? Apparently even though you put your foot to the floor, the computer doesn't always do that right away. It can apply throttle at the perfect based on what it knows which is a lot more than we know. It all got me thinking and all of a sudden I qualified on the pole!

Rudi wrote:

All long tubes will do is allow the car to breath better at high RPM's, not much good for anything else.
 Thats why I like the cast iron HI-Po's, less leaks and easier to connect to.

When I first built my car I used HiPo's due to the less hassle factor and the fact I was using GT40p heads, which restricted headers I could choose from. They went into a full 2.5" x pipe exhaust. Down the track, I added a supercharger/intake/cam, and it was really down on expected power. Both seat in the pants and on the dyno. Not just on the top end, but midrange also. And by top end I mean it was struggling to breath past 5800, which isn't really high RPM's in anyones book. Made 330rwhp at 5800
I then changed heads and went 1 5/8 long tubes. Yes, I know I did heads also, so end of the day I can't prove anything. However, the new heads dropped the compression a full point. I went to 1.6 RR instead of the 1.7's The timing was also backed off by 4dg for the initial dyno re-tune. I expected a bit more power, but not that much until we ramped the timing in, which is why i wanted the alloy heads. At 5800rpm, it had 4psi less boost than before. Before timing was added, it made 420rwhp at 5800. Less timing, less compression, less boost. I have no doubt the hipo's were holding it back big time. The outlets are 2" i beleive. Not enough for hp motors.

Here's is another article where they swapped hipo manifolds for long tubes and gained 100hp. on a 347.

So in closing, hipo manifold might be great for stockish motors, but I believe you are losing a lot on a high performance build. I will also add, my hooker 6901 long tubes are just as easy to change spark plugs. I also changed a set of header gaskets the other week and it was pretty painless.
 

It's a whole new ball game when an engine has power adders. Header and pipe size  rules go out the window since the name of the game is getting the used air out.

I think if they cant cut and weld I might get jbl

Ron68 wrote:

I had Heddman long tube headers that worked with the 351W/C4 setup I had. When I installed the 4R70W trans ( almost like an AOD) they wouldn’t fit, so I went with a set of JBA Shorty headers and they fit great with just one interference issue with the engine block. I trimmed off one small protrusion one the block and no problems.