Rodshop does kits for 4cyl Toranas to fit a V6 ?
Don't confuse a 4cyl body + crossmember with a 6cyl car... nothing is the same
I'm making assumptions here, but they seem pretty open and comprehensive. I'm still waiting on feedback from the email I sent them.
Yes, sedan weights of similar models.
4cyl and 6cyl are not similar. In any case the NCOP is a guide, and the extent to which you choose to deviate will only be limited by how much you can pay your engineer.
Seeing as they both have 'Torana' as a make and 'Holden' as a manufacturer I'd argue they're identical to the powers that be.
The hell with it, have you read the actual document, or spoken to an engineer? I see you have a 4cyl LC, this may be of interest to you. I appreciate it's a guide, but ultimately if you stay within it it's going to be 100% ridgey didge, and that's what matters... to me at least. Here's the relevant part of the document:
2.13.1 Vehicle Mass
The mass of the vehicle referred to in Tables LA1, LA2 and LA3 is the original (unmodified) tare mass of the model vehicle fitted with the largest engine available for the model in Australia but without optional accessories (air conditioning, tow bars etc.). The mass of the vehicle, whether it is a sedan, station wagon, utility, etc., should be based on the heaviest sedan version of the model (not station wagon version) sold in Australia.
Emphasis on "fitted with the largest engine available for the model" and "heaviest sedan version of the model." So be it a 4cyl / 6cyl / 8cyl car, it doesn't matter. All that matters is what that model came with from factory. So HB's are stuck with a tiny weight and engine, LC/LJ about 1070 or so, LH/LX a bit better due to V8 fitments and larger overall weight.
Apologies if I've come off like I've had my feathers ruffled, just trying to lay out some straight information which may be of use to others... and primarily myself at this point in time.
Cheers - boingk