Well it seems to me that v8 swap would be a good swap for a 280zx, but the 300zx on the other hand well I dont think that you would benifit from it! Now lets say that you had the money for lets say sr20det now thats a swap that you would benifit from. One, the motor weight is about one third of a VG30. Two, you could build it to say 500hp and you would be real fast! Three Problems, 1 it would cost you a small fortune for any shop to do any kind of swap 2, You would have to register your car as race only (sr20 motors cant pass emmisions in california, not street legal), 3 just plain costly!!! Now I dont know how much money you can spend but I bet that you dont have the kind of money right now to do what you want to do right now. The VG30 makes really good Hp for the cid, now dont take this negitively but if you wanted a v8 then you should buy a camaro. Now thats just my opinion and you know what they say about opinions there like a##holes everybody has one, and I'm a diehard Zman I'm going on like my 5th or was it my 6th anyway, YOU HAVE A GREAT CAR!!!!! With a little love and an upgrade here and their when money allows that will make it even better! the important thing to remember is that its your car! And you WILL do what you want when ever you want, thats what makes our country what it is! Also remember that we are here to help you to do what you want to do! After all you decided to be part oof one of the greatest families your z comunity!!! Come out for some events, find a local z chapter and talk to the other owners and takke a look @ what they have done to there Z's. There are many other NA 300's out there. I would get a manual for your car, Not a chiltons a nissan service manual hard copy or cd version( I prefer, you can print the pages that you need and dont have to worry about getting them dirty) do the research change your timing belt if it hasnt ben done its tim to do it! give her a tune up oil,plugs,filters (fuel, oil, air). Flush the radiator this is a good start. You can upgrade to an electric fan and put on a lightened main pulley thats good for about 15 Hp! Then you can do an upgrade on the air filter ect.....
good luck with your car hope to zyou out there zing down the road with the rest of us!

 

Agreed.

Any type of swap in the car would probably cost you a healthy chunk of change. You could get better bang for the buck just keeping what you have and modifying it..

Well my 2 cents worth anyway..

 

any other kind of swap of a different motor will cost, period.

as long as you ahve been taking care of your current motor, modifying what you have now shouldnt be a problem.

in other words, wheter you want more power out of what you have or trying to switch to something else you going to ahve to put some money aside to get where you want to be.