dmayoort Posted April 20, 2013 Share Posted April 20, 2013 (edited) Hello. I have bought and engine from a junkyard which has a X20 head and the block has a * between the 20S and the number. I have read that the X20 heads are not suitable to run unleaded but I also have read that engines with the * are.... So, can my head runs unleaded? Thanks in advance Edited April 20, 2013 by dmayoort Quote Link to comment Share on other sites More sharing options...
dmayoort Posted April 21, 2013 Author Share Posted April 21, 2013 Nobody knows? Quote Link to comment Share on other sites More sharing options...
cam.in.head Posted April 21, 2013 Share Posted April 21, 2013 hi. x20 heads are not suitable as you thought. the engine number with the star is on all anyway so disregad that on the cam in head engines. what you need is a head with p2 on it for a carburrettor or p2e for injection. or have yours fitted with unleaded exhaust seats.since you would have to remove your heads anyway why not just run it as it is and see what happens. many of the so called valve seat recession has been overeggagerated.the new up and coming issue nowadays is the e10 fuel thats supposed to be coming in ?????????? Quote Link to comment Share on other sites More sharing options...
dmayoort Posted April 22, 2013 Author Share Posted April 22, 2013 (edited) HI. Thanks for your reply. The engine is an spare one, so I will gave to fit the head with hardened seats Thanks again. Edited April 22, 2013 by dmayoort Quote Link to comment Share on other sites More sharing options...
Jessopia74 Posted May 11, 2020 Share Posted May 11, 2020 (edited) So there should never be an X20 head on a gte block? I have a soare head (in bits), that is stamped up X20 that did come off a GTE 🤔 Edited May 11, 2020 by Jessopia74 Quote Link to comment Share on other sites More sharing options...
cam.in.head Posted May 11, 2020 Share Posted May 11, 2020 hi jess. yes its ok but it will be a pre 85 leaded head .hence normal valve seats rather thanhardened. hi jess. yes its ok but it will be a pre 85 leaded head .hence normal valve seats rather thanhardened 1 Quote Link to comment Share on other sites More sharing options...
Jessopia74 Posted May 11, 2020 Share Posted May 11, 2020 22 minutes ago, cam.in.head said: hi jess. yes its ok but it will be a pre 85 leaded head .hence normal valve seats rather thanhardened. hi jess. yes its ok but it will be a pre 85 leaded head .hence normal valve seats rather thanhardened Ah, ok that makes sense now you have pointed it out, thanks Quote Link to comment Share on other sites More sharing options...
Snowy Posted May 12, 2020 Share Posted May 12, 2020 21 hours ago, Jessopia74 said: Ah, ok that makes sense now you have pointed it out, thanks I have a GTE P2 head if you need one. Much cheaper than converting one to unleaded. 1 Quote Link to comment Share on other sites More sharing options...
cam.in.head Posted May 12, 2020 Share Posted May 12, 2020 yes definately fit a p2( p2e) head if poss.much better than guessing if a machine shop will get it right.a proper gm unleaded head will have been made correctly and to all the right tolerances and as snowy says much cheaper as well ! 1 Quote Link to comment Share on other sites More sharing options...
Jessopia74 Posted May 12, 2020 Share Posted May 12, 2020 2 hours ago, Snowy said: I have a GTE P2 head if you need one. Much cheaper than converting one to unleaded. Thanks for the offer but I don’t use CIH engines now, It was more to know what I had incase someone was asking for one. Quote Link to comment Share on other sites More sharing options...
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