The advantage of the OZ 250-2V head/manifold is that it relives the asthmatic conditions associated with the stock log head without major modifications or multiple carbs being adapted to the log head.  Dyno test have shown that a stock 200ci engine with only the OZ 250-2V head/manifold, a two barrel carb, and headers yielded a forty percent increase in horse power. Flow test results on a stock OZ head were 176CFM intake and 110CFM exhaust. Porting and polishing with most of the attention given to the exhaust runners/ports will yield dramatic increases over the asthmatic log head.

The disadvantage is that the heads were only produced for a few years, and the production ended thirty years ago. Hence, only used heads are available, if and when they can be found. Occasionally, we come across a head for sale. If we purchase it for resale, it is hot tanked and magna fluxed to assure the buyer it is free from defects. The heads normally require a rebuild, including fitment of unleaded valve seats. They will bolt directly to a US 170/200/250 block without any modification to the block or head, and stock non-adjustable rockers (from your old head) may also be used. However it is preferable to upgrade to an adjustable rocker assembly. Roller tipped or full roller rockers may also be used.

CAUTION: Stock or Chrome US valve covers will fit with minor modifications to the gasket retainer rim so that it will clear the OZ head intake runners. This must be observed or you will have oil leaks all over the head.

There are several options for valves. First, it should be noted that the stock OZ valves differ from US valves in stem size. Therefore the valves are not interchangeable, but this is not to say that US valves can not be used.   US valves have 5/16 stems, OZ valves are 11/32, therefore you will need to replace the valve guides to use US valves. Bronze guides will need to be custom made, but steel/iron guides are readily available.

The removable intake manifold accepts a two barrel Stromberg carb, but a Holley carb adapter as well as gasket sets and pushrods are available from Classic Inlines for an additional cost. Modifications will be required to the carb linkage, or a throttle cable may be used instead. The stock exhaust manifold can be used but headers are suggested for optimal performance gains. The use of a port divider available from  is Auto Krafters or Clifford Performance is also suggested.

The trend seems to be to install over sized valves since they will offer the best performance.  It is possible to install 1.75 (intake) and 1.50 (exhaust) but the bowls will need to opened up a little for proper clearance. The machinist will need to use caution when installing the new seats in the number one cylinder, as it is possible to hit the water jacket during the machining process. Classic Inlines stocks 1.75 intake and 1.50 exhaust valves from SI Industries for use with OZ heads (with 5/16 stems). The retainers must also be replaced.  One option is the use of one piece retainer, either from a 260 v-8(which may be difficult to locate) or from a ford 4.0 v-6. These are not required, but are an option. Several manufactures will carry retainers for US valve sizes. Other options include using stock OZ250-2V valves or having custom valves manufactured by various US manufactures, including SI Industries and Manley Valves.  FSPP can order stock OZ valves and/or related parts from Australia upon request.

Complete heads may be available from time to time which includes all used valve train components (valves, adjustable rocker assembly, springs, retainers, locks, etc). Price of the complete head is $875.00, or whatever the current market price is, whether higher or lower.