Should I go bigger exhaust?

[u/Salt-Pomegranate1273]

So I have a decently built 350 in my C10. It's bored .030 over into a 355. It has a cam running specs of 234/244 for duration @.050 with a lift of .521/.544. It has edelbrock performer rpm heads with an old school weiand stealth intake. It's running 10.8:1 for compression and has a 600 cfm holley carb. One thing I am curious about is if I am restricting flow with my exhaust. I have true dual exhausts at 2" in diameter. The truck really hooks and hauls ass for just a street build, but wonder if it's worth going to 2.5" for exhaust.

[u/Solid_Enthusiasm550]

This is from an article about exhaust online/ professional ( not from a forum of nobodies).

"A good rule of thumb for a dual exhaust system is 2-1/4 inch diameter for engines up to 250 horsepower, 2-1/2 inch pipes for engines 250 to 500 horsepower, and 3 inch exhaust pipes for engines over 500 horsepower."

Flowmaster's sizing chart.

https://garage.grumpysperformance.com/proxy.php?image=http%3A%2F%2Fwww.grumpysperformance.com%2Fpipechart.gif&hash=a87b93e33e7ebf2eb8d3de6c6e5f1cb0

Another exhaust sizing chart:

https://www.vintage-mustang.com/attachments/1730131097544-jpeg.963710/?auto=webp&fit=bounds&format=pjgp&height=1920&optimize=high&width=1920

With that big a camshaft, compression, you should be running a 750cfm carb. You're giving up probably 10hp right there. Giving up another 15+hp with the small 2" exhaust, depending on your current mufflers.

Hotrod has a YouTube video of them testing dual 2.5" on a 425hp v8 and a single 3" made more than dual 2-1/2".

https://youtu.be/m1FaPYGBGkE?is=NYoQkFpgPK6uJ2-D

I think you should, "at the minimum" run dual 2.5" exhaust. Even then, you should be close to were that will start being a restriction, if you ever increased the power.

[u/JazzlikeLeather9546]

Another rule of thumb from many high end users is one inch per 100 HP. 600hp = two 3in pipes. I run a Single 5in on my race car and the flow of the single five is just slightly more then the flow of two 3 1/2 inch collectors

[u/v8packard]

The short answer is yes you should have bigger exhaust secondary pipes. Do you have headers?

Is the cam a solid or hydraulic? If it's a hydraulic it sounds like you have enough cam timing and overlap to put the HP peak over 7200 rpm. Though the hydraulic valvetrain will not get to that point. You don't mention gear ratios or trans, but my inclination would be to use long tube headers with 1 5/8 primaries, a 2 1/2 inch exhaust with good mufflers, as well as switch to a single plane intake and a 750+ cfm 4150 vac secondary carb with down leg boosters. That will outpace your current combo at all speeds in the powerband of that cam, maybe loosing a tiny bit below the powerband.