The E-30 heads are 37cc Chambers compared to 39-41cc on the E-31 or E-88. 

I run 37cc chambers on my L24 , but it’s a e88 that has been shaved a bit ?

I also have significant bore notching which lowers compression . That coupled with a 490/290 cam I have no issues with detonation with 93 octane. 

The L20 ran dished pistons with those tiny chambers 

I re-discovered an orphan E-30 head in my pile last month while looking for other things. 

It should find a new home...  hint hint....

On 1/18/2019 at 10:47 AM, zKars said:

I re-discovered an orphan E-30 head in my pile last month while looking for other things. 

It should find a new home...  hint hint....

It would be a great head for a L24 . Not sure how big the ports can go - I know they are smaller . Great chamber design and square port exhaust . 

19 minutes ago, madkaw said:

It would be a great head for a L24 . Not sure how big the ports can go - I know they are smaller . Great chamber design and square port exhaust . 

The ports look pretty little. Assuming the castings are similar to later heads there may be plenty to work with to make them bigger, but no guarantees.

On 1/18/2019 at 12:32 PM, madkaw said:

The L20 ran dished pistons with those tiny chambers 

It's a mistake to talk about the 'L20' six as though it is just one thing. From 1964/5's 'L20' through L20(A), L20AT, L20AE, L20E, L20T and on into the mid 1980s there were many, many variants.

130ps 9.5:1 L20(A) as fitted to the first Fairlady Zs in 1969 and 1970 certainly had flat top - not dished - pistons.

My JDM - 1972 Fairlady Z: L20A engine, E30 head, 38mm carbs HJG38