Originally Posted by a_2000_se
^^^ idk what the Zetec/ATX is limited at.
FYI - There "is" an aftermarket manufacturer with a 'new' cast for the SPI SOHC head that supposedly addresses the dropped valveseat problem and makes it a non-issue. A thread somewhere here in this section during the last year was started on this topic.
The reason I ask, the spi atx will swap over to the zetec. Although it's geared different it works absolutely perfect. I just wonder if it had a different redline than the spi.