Another 2.5 inch vs 3.0 inch?

Kent mosby said
I am prepping the final installs and have a question on exhaust.
My 73 scamp will get its 512 RB installed in the coming weeks. The headers are TTI 440-200 with 2 inch primary tubes with 3.5 collector to 3 inch flange. Trans is 727 and 3.91 gears in an 8 3/4 rearend. Cam grind specs are 244/252 @ .050”, 282/290 adv, .516”/.537” lift(1.5:1 rocker), 112 sep, .016”/.018” lash. Future nitrous is an option but not certain. Holley Super sniper EFI will be installed with the motor.

The question I am debating is do I use 3 inch or 2.5 inch exhaust? I have read a bunch and am still confused.

Then I read this thread New 3" exhaust with 2.5" Tailpipes and yet I did not see any performance evaluation.

I have the 2.5 inch adapters on order but can change them if need be. Thanks for the wisdom.
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with a engine like that I would definitely install the 3” . 2.5 would choke that big engine. Engine masters did a comparison on the dyno with a BBC with basic bolt ons and full 3” with tail pipes and 2.5 and lost quite a bit of HP the 3” was almost as good as open headers I believe it was a magnaflow system. Check it on YouTube. Those engines need to breath!