Triumph Twins Triples Cylinder Head & barrels cast numbers, model, year

Offering information on Triumph motorcycle cast numbers on cylinder heads ( and some barrels) is a bit of a black art. So, please use your common sense and use the following information as a guide, not gospel. It’s confusing enough when Triumph used cast numbers that were often similar (or even the same) to the part number. Note that the same cast number is used for several different part numbers.

In the past, I had a few issues with identification of some cylinder heads and the cast number is usually the only numerical guide that you have. Occasionally, the makers cast a date (month and year) on one of the inside facings. That helped to narrow things down a bit. However, when Triumph were changing over from Pre-unit models to unit construction engines, they seemed to carry on using some of the ali heads.

8-stud heads tend to narrow the date range down on the 650 models, but it is still a guide.

So, the data in the table below is just information gathered over the years, through necessity. I have put them in a rough date order and have shown a cast number on the close fin ali barrel set at the bottom. Probably my favourite of all the pre-unit Triumph engines.

If you’re interested to see what Triumph engine parts that I have, please follow this link. It’s likely that I have other parts, so please ask if there’s something that you need.

 

Triumph motorcycle cylinder heads – twins and triples

Casting # Part # Approx years Model Notes
70-3548 70-3608 1956-57 T110, TR6
70-3548 70-3644 1956-57 T110, TR6
70-3548 70-3553 1956-57 T110, TR6
70-3925 70-3924 1958-61 T110, TR6
70-2679 70-3005 T100, 5T Pre-unit close fin ali
70-3663 1959-62 Bonneville From TR6 casting
70-3925 70-4552 1963-68 TR6
70-3925 70-7031 1963-68 TR6
E3663 70-4928 1963-68 Bonneville
E3663 70-5727 1963-68 Bonneville
E3663 70-5348 1963-68 Bonneville
E5348 70-5348 1964-67 T120
E3991 70-3991 to 1968 T100
70-3991 70-4007 to 1968 T100
70-3991 70-4785 to 1968 T100
70-3991 70-6700 to 1968 T100
70-6851 71-0277 Late ’68- early ’72 T100 Exhaust spigot
70-6851 70-9509 Late ’68- early ’72 T100 Exhaust spigot
70-6851 70-9507 Late ’68- early ’72 T100 Exhaust spigot
E3663 70-9418 1968-70 Bonneville
E9418 70-9418 1969-70 T120
70-3925 70-9362 1969-70 TR6
E12356 71-2356 1971 – early ’72 T120
E12807 71-2807 Late 1972 T120
71-2360 71-2356 1971-72 Bonneville exhaust spigots
71-2358 71-2354 1971 – early ’72 TR6
71-2490 71-2643 Late 1972 – ’74 T100 Push-in exhaust
71-2490 71-3605 Late 1972 – ’74 T100 Push-in exhaust
71-2862 Late 1972 TR6, TR7 Push-in exhaust
71-2863 Late 1972 Bonnevile Push-in exhaust, 10 Stud
71-2862 71-3023 1973 – early ’79 T140 10 stud
71-2862 71-7007 1973 – early ’79 T140 10 stud
71-3779/2 T140E Parallel intake ports, 10 stud
70-2258 Tri 500 Cast iron spigot barrel
70-3699 Tri 350

Triumph barrels

Casting # Part # Approx years Model Notes
E2958 1952-55 TR5, T100 Pre unit 500cc models