I just started my 540 for the first time today and my old 3inch Torque tech exhaust was popping through the pipes.Everyone is saying 3inch is to small for my 840hp/765lb street motor.I don't like the idea of having 4inch exhaust which dumps before the rear axle.I was told that there is some company that makes a pancake 4inch pipe that will go over the rear axle.Has anybody heard of this?

1970 chevelle SS540

http://www.spintechmufflers.com/
http://www.spintechmufflers.com/spintech/spintechindex.asp
Look under accessories.

Thomas

3.5" is more than adequate. 4" is obnoxious. I have ran both behind my 632 and there was no noticeable difference in quarter mile performance.

My 3.5 mufflers were however behind 5" collectors stepped down to 4" pipes to an x where it stepped down to 3.5 then 3.5 straightline performance mufflers and dumps.

For a race once I tried 4" bullets and it was absolutely the same volume as the 5" open headers.

Thanks for your help:thumbsup:

Just logged off Hedman site. Noticed they make a 4" glasspack style - 24" long w/ 5" diam case.

street540,

Since you have the word "street" in your username thought you would appreciate this fact also:

With my 632 and 3.5" exhaust, I could carry a normal conversation inside the car with the windows up - and talk on the cell phone and people wouldn't know that I was in the chevelle.

With the 4" and bullets, I couldn't have a normal conversation or talk on the phone FIFTY FEET away with the car idling!

On my small block Chevelle w/ 3 1/2 pipes with Flomasters you can not even talk in side the car.You have to hollar.Its real loud.I guess its mainly the muffs

Rob

I haven't decided exactly what I'm doing yet but I did think about changing to a step style Lemon header and have it go into a four inch pipe, that goes to one of those stainless electric cut outs.Then it would feed back into the torge tech 3inch to go over the rear axle.I figure that way I could cruze around town with closed exhaust and hit the switch when I run at the track.Plus now I have a Rick's Hotrod stainless steel gas tank in the stock location and I can just barley fit my fingers in between the 3inch pipe and the gas tank. So I don't think any bigger diameter pipe would go over the rear end. I'm just happy to finally have a motor I can run pump gas in.:D

what's your motor combo to get 840 hp on pump gas??

I haven't decided exactly what I'm doing yet but I did think about changing to a step style Lemon header and have it go into a four inch pipe, that goes to one of those stainless electric cut outs.Then it would feed back into the torge tech 3inch to go over the rear axle.I figure that way I could cruze around town with closed exhaust and hit the switch when I run at the track.Plus now I have a Rick's Hotrod stainless steel gas tank in the stock location and I can just barley fit my fingers in between the 3inch pipe and the gas tank. So I don't think any bigger diameter pipe would go over the rear end. I'm just happy to finally have a motor I can run pump gas in.:D

I think Torque Tech exhaust offers a 3 1/2 inch full system now.

3.5" is more than adequate. 4" is obnoxious. I have ran both behind my 632 and there was no noticeable difference in quarter mile performance.

My 3.5 mufflers were however behind 5" collectors stepped down to 4" pipes to an x where it stepped down to 3.5 then 3.5 straightline performance mufflers and dumps.

For a race once I tried 4" bullets and it was absolutely the same volume as the 5" open headers.


I've got 4" bullets that go straight into 4" turndowns on my '67 Fairlane with a 796 hp 514. Doesn't do much to quiet it down at all. I feel guilty every time I crank it up in the neighborhood; kind of shatters the silence.