All Small Six The endless question - engine head code
- Thread starter Ashley47
- Start date
This relates to all small sixes
Um, the Australian heads of that era are always blue as well. The rocker cover, if Original, defined the capacity. Might have been other differences, but the heads were all the same between the 200 and 250.
There is no difference between that head you have, and any other 1972 to June1976 200 or 250 head.
Australia moved to European numberic casting codes. For early engines, it was ARD1 etc. Australian, Argentina, Revised. 1971. Same heads between 200 and 250 as well.
No cc differences, the compression ratio changes were from the piston cc which varied 15 cc between the 200 and 250. A taxi low compression existed with 250 deep dish pistons on the 200 engine. Still the same one size fits all head.
There is no difference between that head you have, and any other 1972 to June1976 200 or 250 head.
Australia moved to European numberic casting codes. For early engines, it was ARD1 etc. Australian, Argentina, Revised. 1971. Same heads between 200 and 250 as well.
No cc differences, the compression ratio changes were from the piston cc which varied 15 cc between the 200 and 250. A taxi low compression existed with 250 deep dish pistons on the 200 engine. Still the same one size fits all head.
It's all good. I have seen some 100% red engines, in the Cortina 250, and the Falcon 250.
For all the August 71 "72" heads, the camber capacity is 59 to 62 cc for all 200 and 250s, and probably the earlier 1968-1970 221 sixes as well. The log type is Flat top log, similar to one kind of 250 US and 200 C9 head. After that, the US and ARC9 and ARD1 and "72" heads changed in detail.
The valve stems were enlarged to 289/302 and 351C sizes in 1971, and after 1968, the intake log hole became 1.6875 inches, with the US style down shift arm kickdown boss added with casting ARC9, but it's undrilled for the hexagonal bolts. I'm sure the 72 continued with that boss, because around 30 % of every six cylinder 200 or 250 engine got the optional US C4 gearbox. Everything else was 4 speed Top Loader, or Borg Warner Single rail 3 or 4 speed, or BW 35 series auto. The linkages for those were the Bendix Stromberg Technico BXV 1 bbl carb, which was an ancient Chrylser Plymouth Dodge flat head carb.
The Vaccum take off is not Load-a-matic, it's a simple beside the carb coupling, where both the brake booster and vacuum advance tee into. The later Bendix Stromberg Technico has a different kind of Aluminum tube to the Bosch or Lucas distributor.
Basically, the advantages of an Aussie casting are that it fits one kind of old triple Offenhauser tripower intake, but not much else. An Australian 72 to 76 log head might take continued abuse longer than the smaller guide valves, but US engines had a better kind of steel in its valves than Australian engines, and after 72, they started getting exhaust valve seat induction hardening and then inserted valves, which no Aussie log head ever got.
The rocker systems are US style, just make sure you use the right kind of oil head stud if you are using non adjustable rocker gear.
For all the August 71 "72" heads, the camber capacity is 59 to 62 cc for all 200 and 250s, and probably the earlier 1968-1970 221 sixes as well. The log type is Flat top log, similar to one kind of 250 US and 200 C9 head. After that, the US and ARC9 and ARD1 and "72" heads changed in detail.
The valve stems were enlarged to 289/302 and 351C sizes in 1971, and after 1968, the intake log hole became 1.6875 inches, with the US style down shift arm kickdown boss added with casting ARC9, but it's undrilled for the hexagonal bolts. I'm sure the 72 continued with that boss, because around 30 % of every six cylinder 200 or 250 engine got the optional US C4 gearbox. Everything else was 4 speed Top Loader, or Borg Warner Single rail 3 or 4 speed, or BW 35 series auto. The linkages for those were the Bendix Stromberg Technico BXV 1 bbl carb, which was an ancient Chrylser Plymouth Dodge flat head carb.
The Vaccum take off is not Load-a-matic, it's a simple beside the carb coupling, where both the brake booster and vacuum advance tee into. The later Bendix Stromberg Technico has a different kind of Aluminum tube to the Bosch or Lucas distributor.
Basically, the advantages of an Aussie casting are that it fits one kind of old triple Offenhauser tripower intake, but not much else. An Australian 72 to 76 log head might take continued abuse longer than the smaller guide valves, but US engines had a better kind of steel in its valves than Australian engines, and after 72, they started getting exhaust valve seat induction hardening and then inserted valves, which no Aussie log head ever got.
The rocker systems are US style, just make sure you use the right kind of oil head stud if you are using non adjustable rocker gear.
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