collector length

[supernaut]

I've read a few technical exhaust articles and it seems like the collector is the most important thing for a nicely tuned exhaust w/headers. I have not seen any formulas for figuring the collector length tho. Anyone have that?

I have a '75 350 350 203 33's 4" 12 bolt corp dana 44 with a carter afb sitting on the intake. when i start doing a re-build on a separate 350 core I plan on building for torque and that's the engine I want to design the exhaust for.

 

[dyeager535]

Did you read the one by David Vizard?

IIRC finding the right length of collector isn't something you can just figure out via formula, the "optimum" setup needs to be tested. From what I read between the lines, you'd have to try a bunch of combo's to get the most power through an exhaust system.

Don't get me wrong, the gains are impressive, but for the difficulty level, if you weren't seriously racing, the gains aren't worth the effort/expense of testing everything.

 

[supernaut]

I think i remember that article, was that the guy who was talking about inventing the first high performance muffler and then he was talking about flowmaster? Well if that's the case then I won't worry too much about it. i'll just make sure and have a collector of whatever length is generally recommended for torque. anyone know what the collector length should generally be for a 350 built for torqe (moderate build)?

things I'm certain of so far

• headers

• I'm not cutting off the collector like someone suggested just to remove a possible point of failure for exhaust leaks

• dual exhaust if for no other than it's cool as hell and i always wanted them

• a crossover pipe

things I'm not certain of

• which headers

• what length the collectors should be

• which muffler will give me a throaty godzilla roar

• if i should put a resonator in

 

[dyeager535]

Only suggestion I can really give is on the headers.

For a moderately priced pair, the Hedman Elites are fairly impressive. Thick flanges, pretty thick tubing, already have eliminated the leak prone exhaust flange, and are ceramic coated on the outside. Clearance is good, #5 only hard plug to get at, (open end works, others all socket fits) shackle bolts only interference point, and I had to slightly bend the headers to clear with a 2x4 once they were bolted up.

IMO that slight bit of clearancing required was worth the (minimal) effort compared to the nightmares I hear people having of spark plug clearance with other headers.

Summit had them for around $200 last I checked, half as much as they cost locally.