Petrolblu

Hi all, my 1977 euro needs heads due to corrosion. I have found some good 3561r heads. Does anyone have experience using these to replace 345 heads?

thx!

Rob Edwards

I think you're referring to casting numbers- The '356' heads are from the M28.21/22 motors (and perhaps the M28.11/12 too? dunno) and are basically 2mm bigger in every important dimension (valve diameter and port size), vs. the M28.01/02/03/04 '345' heads.

So you could use the 356 heads but you wouldn't derive any benefit from the bigger valves. I have to imagine that 345 heads are plentiful, I think I'd save (or sell) the 356s for rebuilding a Euro S motor.

Petrolblu

Thanks for the quick response! Yes. I’m referring to the casting numbers. So. No benefit, but no detriment? They could be used without modifying anything else?

GregBBRD

Totally dependent on the size of the combustion chamber. If the Euro head is smaller or bigger (highly likely), the compression ratio will change.
And the larger Euro port and valves will decrease the velocity through the head, reducing the power in the lower and mid rpms.....something not desirable in a 4.5 liter CIS engine!

You should find the correct heads.
They should be plentiful and easy to get.
Try 928 International...they should have stacks of them.

FredR

Appreciate if you can post a pic or two of the corroded heads.