235 kit will not work on the 228.
The head on your 228 is prone to cracking. Have it cleaned and magnafluxed before rebuilding it. There are venders who sell all the necessary components for the head job. I believe best gasket and felpro have gasket kits for the gmc engines. There is plenty of info on these gmc inlines at oldgmctrucks.com or on the inliners site.
John
