I picked up my 67 M715 a few months ago, and I've been doing tons of reading on what to go with for my drivetrain. This is going to be a "daily driver" type vehicle that I plan to use on and off road (80% on, 20% off for hunting). I've looked at several different options for engines (LS-gas, 6.2 Detroit, 5.9 cummins-Diesel, Tesla swap-electric), and I ran across someone who yesterday who does diesel swaps that said I should steer clear because of the noise in the cabin.

I plan on insulating the whole cab to quiet things, but my question is how loud each engine is in the cab? I've searched the forum and can't find much on noise levels, unless you're talking about the 4bt. I'd like to be able to have a conversation at normal levels, which is pushing me towards the LS, but I like the economy and power from the 5.9.

I'm already planning to replace the NP200 to reduce the noise, but I'm just wanting to know what to expect. If there's anyone near Houston with any of the engines listed above that would let me come see their truck I'm more than happy to make the drive. Thanks in advance.