Luke-Ingersoll Rand builds excellent compressors and even the low end models found at tractor supply are far better than the CH outfits. Sometimes you will find "peak" HP ratings on even the Ingersolls on the smaller models but they do give the real HP rating also and the CFM ratings, which is what really matters anyway, are far more reliable on them than on the "bargain" brands. Ingersoll is a major builder of commercial duty compressors for heavy industry and has been for many years so they have a reputation to protect and they build a quality product and they stand behind it.
Chevelle-1.75@115 is definitely realistic but since this is a homemade outfit you would need to measure the output with a flow meter to know how much air it produces. The direct drives are not only loud but the real problem is that they generally have a very low CFM output, run really hot and are not very durable, they just simply wear out in a hurry.