Fitting of an exhaust system

[Strat Fan]

Acousta Fil seems to be well regarded, shop around, prices vary.

[rutthenut]

Those original silencers definitely looked pretty small for the engine (though expect they sounded good). For info, the Hawk silencer box incorporates a double run for each bank. Manifold link pipe goes in one side of the box, out the other to a loop then back in for further silencing before exiting.
This pic here may help explain
HF3000 24v Exhaust by rutthenut, on Flickr

In any case, your larger silencers look like they should allow you to control the noise levels well enough.