physical differences between early coscast and later coscast head

[mirpur]

is there any way of telling whether a head is early or a late coscast head without having to dismantle it ie any phsical differences between the two

[Belmont turbo]

early coscast on the right GM left i think late coscast have the part number on like the GM but still have the Z shape ridge

[Cavalier-C20LET]

plus if you look underneith the car if you can with a light it says "coscast" on the bottom front of the head

[Melv]

One for bookmarking

identifying a coscast head

[Belmont turbo]

One for bookmarking

identifying a coscast head

they're my pics the tea leaf haha

[mirpur]

Identifying the coscast isn't the problem its more to identify the differences between the two coscast heads there is an early coscast and a late coscast

[Gordo]

The picture above is an early Coscast head.
According to this picture, from SBD*, the 'new' Coscast head has a couple of additional lugs - I assume for the coilpack?




They have some new castings for sale, quite expensive, though...

[steveboyslim]

The picture above is an early Coscast head.
According to this picture, from SBD*, the 'new' Coscast head has a couple of additional lugs - I assume for the coilpack?




They have some new castings for sale, quite expensive, though...

SBD are sold out of new castings.

Steve

[Davey j]

Quickest way is on the cam caps for age. 88/89/90 are early and the later ones are 93/94 if mem serves. It's embossed on the cam caps in a circle any way. Later ones have GM stamps on the side next to the water outlet on the head but still have the Z step ledge like on the early ones and later ones may or may not have Dispak lugs depending on whether they were fitted to a Cav SRI/Calibra on motronic 2.8 or the LET engines which didn't have them.

[mirpur]

Mine has 95mm caps so I presume its later with 13mm guides