This is a completely rebuilt, YUGO cylinder head. It is applicable to carbureted 1.1 and 1.3l SOHC engines with a 10-bolt, 12mm stud engine block, as fitted to all Fiat 128, Fiat X19 from 74-78, and Yugo. Not recommended for 1500cc SOHC engines. Be sure to check out the multiple pictures!
This head is cast from the factory as a "euro-style" unit without the .075 deep chamber in the head that all North American spec engines received. This results in a bump in compression for 1.3L engines and is the preferred method of increasing compression in 1300 engines while maintaining stock cam timing geometry and allowing use of the 1300 sized tension bearing. Throw in a hot cam, and a good valve job, and this unit will really wake up the performance of your 1300 engine.
We start with a very good condition Yugo carbureted head, with 12mm head bolt holes. All threads / stud holes are intact, and clean coolant passages absent of corrosion or enlarged openings. All spark plug and coolant sensor holes have clean threads, and we replace any valve guide whose measurements are out of spec.
We mill the head and cambox surface a minimum amount to ensure straightness and help prevent annoying cam-box oil leaks.
We tap and plug all emissions ports, and tap the intake manifold coolant holes with a 5/16 x 20 thread so that they can be easily blocked if desired. A trick three-angle valve cut on the seats which has been flowbench proven to increase flow by nearly 40%! New competition valve springs with stock retainers are used, which are guaranteed to put up with a high RPM beating up to 9K RPM without danger of valve float.