Pat is 100% correct on the 240sx rust. if you look at one look it over with a fine tooth comb. The sr20det swap is pretty easy, ive done a handfull of them. Pat, i was referring the the Z32, those cars esp. the turbo suck big time to work on, and the vg30dett isn't the best engine.There are plenty of aftermarket parts avail. for the MKIII Supra. if you can find a turbo model, and exhaust, intake and boost controller will wake it up for cheap money.
Totally agree with you on the z32... I would take one... but with an RB not the stock motor.
I haven't heard much as far as good or bad about the na VG30de but if its like the twin turbo motor it sucks.
MkIII supras are fun little cars... The one down fall is that the 7mgte has head issues, mainly headgaskeys and warping. If you grab one buy a Good headgasket, some headstuds then mod it.
The 7mgte is a great engine just the stock headgasket is junk. If you put some time and money into it you could have a very fast car.
as for strongest NA motor???
IMOP, (strongest- weakest NA MOTOR TO TURBO ) For cars in sub 8k price range NON Domestic-
from what I have seen in this order these can hold the most power when turbo is added-
S50/s52 (bmw m3 US) aprox 500+whp, 1uz-fe (v8 sc400/gs400) would supercharge or ITB, 2jz-ge (NA sc300/gs300) seem to have hg issues def not as strong as the 2JZ-GTE counterpart, VG30e (et) (from z31)400-500whp, M50tu-b25 (bmw 325i/is E36)400+whp, M20b27 /m20-b25 head (e30 eta with I head turbo swap only)400+whp, m20-b25 (bmw 325i/is)400+whp, m20 super eta (e30)400+whp, Stock m20-b27(e30) 300+whp mine held 15psi before I did the I head swap(18psi)... biggest issues are the head low rpms and weak valves, Ka24de 250-400whp (these are strong but sometimes go boom... I have seen a ton make it and a ton fail).
then weaker and wouldnt add turbo to-
vg30de (z32) Just dont know anything about them, 7mge(cressida/supra) hg issues.
This is just a list of motors I like that are NA and if I had I would turbo or supercharge... I tried to list as to what I like and feel is the Safest to boost/most power(from cars I have seen an read about)
One to know about the z31 300zx is that it came stock (in Japan) with a RB20det... so its pretty easy to swap an RB series motor in.