Re: Proper sized exhaust
 

While calculations show 500 CFM to be overkill on a 305 running at factory designed engine speeds, as with many things, calculations do not represent real world results. More than likely, the same engine with a 500 CFM carb will make more horsepower than the same engine with a 350 CFM carb, or the factory carb.

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Turbobill. I fully agree with you on that:upyes: Years ago I tested all 3 of these carbs on my 68 305E and the Holley 500 was still by far the top performer, it's all about the real world results:thumbsup:

Re: Proper sized exhaust
 

Back to JB's question. Funky's video spells it out in the opening screen: 2 1/4" opening up to 2 1/2", with an X-pipe and dual exhaust. You can change the sound with different mufflers and pipes after the mufflers. Thanks Funky, I enjoyed every note. The PO of my truck put the mufflers under the cab--with no pipes after. Talk about loud with a "Wheels of Tragedy" scenario.

Re: Proper sized exhaust
 

My exhaust manifolds measured 2.25 so I went with 2.25 inch pipes to the muffler and exited the muffler with 2.5 inch tail pipes. True duals. No cross over. :ok:

https://www.youtube.com/watch?v=RCfanx30JO8

Re: Proper sized exhaust
 

I always thought those 40's would sound too loud ,
but they seem tame enough on you video TJ.
How are they on the highway?

Re: Proper sized exhaust
 

I am a young buck so loud may have a different meaning to me. haha

Personally I like a little bit of Loud so it may be harder for me to say. The 40's were actually Quieter than I expected. Cruising down the highway at 2400 RPM they are very quiet. At 2000 RPM they Can get a little annoying if you don't mind some cab noise. But floor that sucker and rev it out and at 2500-3500 that tone will bounce off of fences and canyons and put a big smile on your face. lol I will be doing a wot run/driving video soon.

Re: Proper sized exhaust
 

[/QUOTE]Turbobill. I fully agree with you on that:upyes: Years ago I tested all 3 of these carbs on my 68 305E and the Holley 500 was still by far the top performer, it's all about the real world results:thumbsup:[/QUOTE]

Exactly!!!! Math results aren't Everything.

According to Math the small 2 stroke chainsaw engine is not supposed to even run. BUT! They run very well and very efficiently. Real world is what matters.

Math would show that my 600 edelbrock 4 barrel would drown my 305 out, yet it performs rather well! :thumbsup:

Re: Proper sized exhaust
 

Here is a video of a 305 with flowmaster 50's. Bout the same, but at RPM they are supposed to be tamer than the 40's.

https://www.youtube.com/watch?v=FkpTLxOj-rI

Re: Proper sized exhaust
 

Ok thanks Guys, I'll go the dual exhaust route with 21/2 pipes and a cross over.

Jake

Re: Proper sized exhaust
 

Be sure to post a video!

Re: Proper sized exhaust
 

I'm pretty happy with 2 1/2 inch duals and 50 series mufflers on my 68 478M, of course that's the same system when I had the 305E, In the future I may switch over to 3 inch pipes and 40 series mufflers:teehee: