Page 1 of 1

4AC Head on 20V S/T Block?!?!

Posted: Wed Oct 09, 2013 2:04 am
by AidoKsev
Hey guys, recently my car got defected (I'm in Australia) for having a 20 Valve motor in my KE70, and I cannot get it over the pits as it has too much powahhh, therefore it has to be certified by an engineer, which is a minimum of six to eight weeks before anyone can come and sign off on it. However it is legal to have a 4AC in there due to the fact they came factory with them. I'm just curious, has anyone tried putting a 4AC head on the Silvertop 20V block?? I know it sounds stupid but it would be super cool if I could get away with it without having valve clearance problems! Then they will record the 20V engine number off the block and I won't need any engineering if I get defected again!

Any help on this topic is appreciated!

Cheers, Aido.

Re: 4AC Head on 20V S/T Block?!?!

Posted: Wed Oct 09, 2013 10:01 pm
by grappletech
I have never heard of this, I have seen a 4ag head on a 20v block though

Re: 4AC Head on 20V S/T Block?!?!

Posted: Thu Oct 31, 2013 8:14 am
by 8Ton
The 4AC head has 32-33cc chambers vs silvertops 35-36. The AC chambers could be deshrouded, which would help flow and keep your c/r manageable. If this is going to be a long-term fix, I would look into portwork, a better intake mani and a reground cam to bring back some of the fun. Good luck!