Hi, I'm new to this site and seeking help on my exhaust system. I'm currently installing a F2 procharged 540 with EFI in my 79 camaro. My plan is dual purpose street strip and I need an exhaust system that will be quiet enough to drive on the street, yet flow enough to run at the track without killing off a bunch of HP. I've got Lemmons stepped headers, 2 1/4 to 2 3/8 into a 4 1/2 collector. I was thinking about wacking off the collectors and installing a Borla or Dynatech headder muffler then pipe back and install another muffler. It's real tight underneath the car for a 4 1/2 inch exhaust, probably have to step it down to 4", and not much room to pipe back before I hit the ladder bar cross member. For a little more ground clearance, I was looking at the spintech mufflers with their oval design, but I'm not sure about their flow, they look restrictive to me. I realize I'm asking alot by trying to keep this thing quiet with a 4 - 4 1/2" exhaust, but I was hoping somebody had a similar experience?

have you looked at the race series of spintechs ?? . they have a muffler that we use on our dirt late model that is 12"x8"x4" case with 4.5 inlet/outlet.it's there most popular muffler with 360/410 sprint motors and able to support up to 850hp. they're DBA @ 100' is 98dba.
the other popular muffler is the flowmaster delta force race muffler 1 chamber. it's 13"x10"x8" with 4.5" inlet/outlet and also used on 360/410 sprint motors

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1972 chevy camaro ss 350 sbc 425 hp/356 @ the wheels,350 trans,373 gears,daily driver with restification in progress for that old school day 2 look ------- future plans- turning it into a baldwin motion Z30 clone
"IF IT'S TO LOUD YOUR TO OLD"
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I've heard the delta force and that's a very loud muffler, it's OK puttin around but when you stand on it, holy crap! I don't have any experience with spintech, are they just as loud? And would you rate the race spintech's as good as the delta force as far as flow and HP potential?

<font face="Arial,Verdana" size="2">Originally posted by blown rat:
I've heard the delta force and that's a very loud muffler, it's OK puttin around but when you stand on it, holy crap! I don't have any experience with spintech, are they just as loud? And would you rate the race spintech's as good as the delta force as far as flow and HP potential?</font>

yes the spintechs are awesome mufflers for high HP and flow.have you gone to there website http://www.spintechmufflers.com go to there products page and click on the racing mufflers and check out the specs on the racing mufflers they carry

In my experience having a Spin Tech muffler is pretty much the same as not having any muffler at all. Those things are LOUD.

My suggestion is the Borla XR1
http://www.borla.com/xr1.sportsman.oval.mufflers/?cartID=2004121218083024.6.40.41
Part # 40948 in this case.
If those are too loud than you can always add Resonators ahead of the mufflers.
Do not weld mufflers directly to the collectors, they will not function properly and will cause all sorts of strange turbulance in the exhaust

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1971 Camaro
383 stroker ~500HP
M21 4spd
12" brakes
16x10" Wheels
Autocross competitive
Sales / Tech - The Speed Merchant, San Jose, CA
1-800-994-0930
mailto:BrettK@speedmerchant.comBrettK@speedmerchant.com</A>
http://www.speedmerchant.com/

Guys, thanks for the input. I've decided to install the Borla shorty collector muffler and their sportsman oval muffler. The collector mufflers have a 4 1/2" exit which I'll fab up and weld an adaptor flange to mount a 4" reducer pipe for the 4" mufflers. I'll pipe back as far as I can then mount the mufflers. Hopefully this arrangement will keep me quiet enough to be legal, and when I want to race I can unbolt the exhaust pipe and mufflers for a little extra breathing.