What size exhaust for a 454BBC

[scf100]

What size are you guys using especially with headers?......

want to keep the sound reasonable!

[kwmech]

No headers for me, went with factory cast manifolds with a clean 350 HP? (estimated) engine. 8.8-1 compression and a 268 comp cam. 2.5'' pipes out of the cast into a flowmaster Y then to a single 3'' through a dynomax muffler and out the back. I can light up the duals from a standing stop

[weq92f]

Originally Posted by kwmech

No headers for me, went with factory cast manifolds with a clean 350 HP? (estimated) engine. 8.8-1 compression and a 268 comp cam. 2.5'' pipes out of the cast into a flowmaster Y then to a single 3'' through a dynomax muffler and out the back. I can light up the duals from a standing stop

.

Similar here:

396, 9.5:1, comp xr270hr , hedman 68198 full length headers into 2.5 inch pipe with H-pipe near tranny tail section, through magnaflow muffs and straight out the back. No drone and relatively quiet inside but she barks pretty good from the rear. Oh and the torque available to my right foot is CRAZY!

My 295x20 meats are turned via 700r4 w/~3000~ stall through a 3.73 posi. It will spin them from a standing start but with just a little brake to prevent rapid forward motion, I can light them up completely and paint crisp arcs of rubber on any dry road surface!

-Kevin

[Stocker]

Ancient history, not really relevant I suppose..... My old (new when I bought it) '69 El Camino had an underrated 375HP 396 L78 engine. Chevy equipped it with dual 2.5" exhaust. I had a lot of fun with that car / truck.

[KQQL IT]

Dual 3 in h or x and 18in magna flows

[Steeveedee]

I had a '68 Skylark that I put a 305 SBC engine in. I put a 2-1/2" exhaust system on it with headers and Flowmaster mufflers. WAY too loud. As for performance, I took it to a muffler shop and they installed 2-1/4" Flowmaster mufflers. I was short on time, as I traveled a lot for my job back then. Even with that puny 305 SBC, I could instantly see lower performance at WOT with the smaller muffler. I wish I had known about those Cadillac mufflers before that. At least the small diameter mufflers were quieter.

[Mike C]

2” header and dual 2 1/2” exhaust should support 600 wheel horsepower. Personally, I think 3” exhaust is just way too loud and doesn’t add anything useful to a street vehicle.

[D.B]

My 72 C20 has a 511 with 600hp drives thru a T400 (2400rpm stall), Gear Vendors to a 4.10 Dana 60. I have Tri-Y headers to 3" pipes with "H" pipe at the tail end of transmission. Then thru Flowmasters out to rear. Great sound, not loud in the cab. I can listen to my radio or my cell with no issues. I also sound deadened/heat barrier the interior which helped a lot.