every article i have read that has done a comparrison of the 6 & 8 from the toyota nissan variety has come up with the 2jz winning the 6 and the 1uz winning the 8. as for old datsuns running on many ks... any engine thats looked after will do that. my suzuki hatch 800cc has over 450,000ks on the original engine and runs fine. and i see alot more old celicas on the road than i do 240z. with the 1uz being able to hold more power thru stock internals than the nissan counterpart and the more available aftermarket parts, combined with the very cheap price of 1-1.5k aus they are my choice. and i have measured everything up and they will fit just fine!!