I would like to know what head should be installed on a 1970 240z ?

The original head was cast with E-31 on it.

FWIW,

Carl B.

Info

Datsun L-series cylinder head timeline

Can you give some background to the question?

Do you have a block, but no head? Or you have a head but its not repairable?

The L24 used the E31 en E88, thats all documented in the link in Pomorza's post.

The L24 used the E31 en E88, thats all documented in the link in Pomorza's post.

Documented there but I believe incorrectly.

1970 & 71 240Z's used the E31 Head - That shows E31 on the 70 only.

1972 Used the E88 and 1973 Used E88 - but they have different combustion chamber shapes.

The E31 is not uncommon - it was used on at least 42,000 240Z's in 70 and 71.

The first E88's did come on a few 1971 240Z's at the end of the production run - but they still had the 42.4 cc combustion chambers. The E88's that came on the 72 240Z's had 44.7cc combustion chambers of the same design.

The E88's that came on the 73 240Z's had redesigned combustion chambers with 47.8 cc volume. They were redesigned for emissions - and they actually had a high or raised quench area - good for emissions not good for performance. The E88 that came on the L26 had the same combustion chamber design as the 73, only it came with a larger Exhaust valve 35 mm vs 33 mm

People Like the N42 - because the combustion chamber design is the same design as the E31 and 72 E88. It has the same silicon/bronze valve seats as the E31 & E88 {none ever had soft brass}. The N42 has a 44.6cc combustion chamber volume - where the E31/E88 had 42.4 cc's and 44.7 cc's. The N42 had larger Intake and Exhaust valves than the E31 or early E88's - N42 44/35 vs E31/E88 42/33

People also like the N42 because it is a direct bolt on replacement for the E31/E88's - and offers the larger valves.

FWIW,

Carl B.

Edited February 9, 201312 yr by Carl Beck

The timeline gives some basic numbers, but not nearly as accurate as Carls description. I'm pretty sure my 9/71 has the early small chambers.

It might be the last month for that design.

I picked up 2 240z 1970 cars, and one car has e88 and the other has e-31 head both has matching numbers block I was going to make one good car out of them low number 240z's also how can you tell if it has a 4 or 5 speed in her.

I also picked up a 1971 with 29,000 miles on her and i know where 3 more 1970 cars are close to me i will pick them too soon.

.... also how can you tell if it has a 4 or 5 speed in her.

You can't shift a 4 speed into 5 gear....

FWIW,

Carl B.

the transmission is out of the car I would like to know it there is a way of telling if 4or 5 speed .

Check this site.

transmission

It shows the difference between the F4W71B, F5W71B and the F5W71C.

Chas

The 4-speeds have a steel plate (with the vent on it) bolted to the top of the tail shaft, just ahead of the shifter. The 5-speed does not, the vent goes directly into the aluminum case.