What is best head to use with flat top pistons, M10 carb.

[Ray_73Turkis_OH]

Hi,

 

we need a new cylinder head.

 

What is best head to use with flat top pistons, 2.0 M10 carb.

 

And, do you have one 🙂

 

Thanks,

Tom and Ray Daley

 

 

[Tommy]

The one with smallest chambers, 121.

[resra]

So from factory the 121 came with mild domed pistons.

 

The e12 with mild domed on standard 2002 and high comp 9.5:1 on tii. 

 

The e21 Flat top pistons.

 

 

[jimk]

Flat tops were used in carbd 71s 121 head until the E12 head came out.

[tech71]

4 hours ago, Ray_73Turkis_OH said:

What is best head to use with flat top pistons, 2.0 M10 carb

121 or 121ti will give you 8.5:1 compression ratio

E21 2.0 will give you 8:1 compression ratio

Either would work fine for a stockish street engine.

The E21 2.0 may be easier to procure, a few new ones may still floating around as well.

They were fitted to 1976 49 state 2002s and 77 78 79 E21 320i

The 320i version works fine but lacks a fuel pump boss so an electric fuel pump must be fitted when using those.

Seems relatively hard these days to find a non cracked 121 head.

Edited July 27, 2023 by tech71

[tech71]

4 hours ago, Ray_73Turkis_OH said:

And, do you have one 🙂

Not that I'm willing to part with, sorry

Edited July 27, 2023 by tech71