New guy from vic

Re: Engine noise.

Mass Loaded Vinyl is the go.  I have an Isuzu 6BG1 next to my knee in the bus/motorhome. I can talk to others and listen to the radio. Brilliant stuff.

Use PVC pipe glue to join it.  (overlapping edges).

This mob sells it, there is a depot out the back of Yarraville. Good for off cuts too.
www.soundproofingproducts.com.au/product...ss-loaded-vinyl-mlv/

I was offered to operate one of these monsters many years ago. I declined the offer  knowing tgat the boss had a tendancy to not tell you everything about the jobs. 
as for sound n heat proofing I used that srlf adhesive stuff from Bunnings wit sticky tar like stuff one side n heat reflective alfoil on the outside, worked a treat made tge cab cooler n quieter.