How to clean, inspect, and determine what you can do with your cylinder head. Also how WHAT you do affects your oil system. There are many variables at play when you make changes to your cylinder head deck from your oil system, compression ratio, your valve timing and potentially even disaster. ‘best not to go that far with it. Watch this video and avoid it if you’re building your own 4g63 head.
The differences between this head and a 1g head are mostly related to port sizes on the intake and exhaust, and different sized head bolt holes. The 7-bolt uses an 11mm bolt, and a 6-bolt uses 12mm. 1g heads have gigantic intake ports, but aside from that, valve geometry, oil system functionality and the service limits are all the same.
Also, click these links for in-depth discussions about oil port modifications for all generations of Mitsubishis, and specifically for 2g head installations on a 1g block.
4g63 Oil Port Modification:
https://www.dsmtuners.com/forums/newbie-forum/341028-4g63t-head-oil-port-mod.html
2nd gen head on a 6-bolt block:
https://www.dsmtuners.com/forums/cylinder-head-short-block/341885-oil-port-mod-2-4g63t-2.html
Possibly 2 of the best threads on ‘Tuners for anyone considering a 1g-in-a-2g or for anyone that wants to know everything about a DSM oil system.