Last week I bought a 72 240z 4-speed with 64,000 original miles on it however it has been garaged for the last sixteen years. I know all four previous owners through friends and work and only one has driven it hard. I'm haveing trouble deciding whether to rebuild the original engine with a triple carbs setup or replace it with a 280zxt engine and trans. There is no budget (The Automobile is an obbsession) and I would like between 300 and 400 horses. Any opinion would be greatly appreciated.

 

you would need a turbo to puch above 300HP. So do the L28ET

 

Does the car have matching numbers ? If so i would keep the original engine ... worth more $s. 240Z with L28ETs are becoming more and more common.

 

If the numbers match, store the old engine - you may wish you had it someday.
For 300-400 HP, you might consider a V-8 conversion.