657x cylinder head

[TheGunMan]

Hi,

Is there a difference between cylinder heads for 657x and 657

I have '95 GTX which needs new head

In the parts list for 95 GTX the part number for rhe head ends on 913 706 but on my old head it says 913 705

Is head listed under this number 290913706 / 420913706 work with my engine?

Thanks

 

[tab]

Yes there is a difference in the head between a 657 & 657x engines. The 657 engine has a step between where it mates to the cylinder and the start of the dome of approximately 1mm. If a 657 head is used on a 657x engine you will lower the compression ratio. If a 657x cylinder head is used on a 657 engine you could end up with piston to head contact which could be poorly fixed with an excessive number of cylinder base gaskets. You can check piston to head squish gap which should be 0.9mm - 1.3 mm

 

[gullwingcorsair]

Yes almost completely different. Here is some great information. http://www.pwctoday.com/showthread.php?t=262412