im just curious which route i should go. i dont want to run premium gas either. **** is too expensive nowadays. its 2.69 for regular in ny

 

well if you allready have an a6 they i would just get a y8 head and obd1 conversion harness and an ecu
but if your talkin about swapps then just do the d16z6 and obd1 conversion harness and ecu

 

sorry as far as streangth goes i've heard the a6 block is better but i don't know so my vote is for the a6 with y8 head

 

Without a doubt, the A6 bottom end has been proven stronger. The A6 uses a cast iron main bearing assembly versus the cast aluminum of the Z6 and Y8. Also, the A6 cranks oil better because they had a stock 45 degree chamfer in the oil holes of the crank. Only the early Z6's had it, then it was no more.

Also, using the A6/Y8 combo will yeild a much higher compression ratio than that of a Z6. So if your going all motor, then that is certainly what you want. The Y8 heads use a closed combustion chamber, so they have an advantage over the Z6's in terms of compression, but that's about it. Testing has shown, that the Y8 is at a huge flow disadvantage due to an emissions based design on the intake ports. The z6 heads are preferable for building if that's your intention. When ported the Z6 will blow a ported Y8 out of the water.

That being said, when speaking in terms of the D, the Z6 head/A6 block is probably your most available and best option. Wanna step it up a bit, throw some 88-89 ZC pistons and rods in there and you've got the strongest D rod coupled with a pretty stout compression ratio.