UK vs UK — 1961 vs 1975
| TR4 IRS | TR7 Drophead | |
|---|---|---|
| Horsepower | 104 hp | 92 hp |
| Torque | 128 lb-ft | 112 lb-ft |
| Engine Size | 2,138 cc | 1,998 cc |
| 0-60 mph | 10.9 sec | 9.1 sec |
| Top Speed | 109 mph | 109 mph |
| ¼ Mile | 17.9 sec | 17.0 sec |
| Weight | 2,249 lbs | 2,238 lbs |
| Wheelbase | 2,235 mm | 2,159 mm |
| Length | 3,962 mm | 4,064 mm |
| Units Produced | 28,465 | 112,368 |
| Original MSRP | $2,800 | $7,000 |
| Value (Excellent) | $50,000 | $25,000 |
| Collectibility | 6/10 | 4/10 |
| Rarity | 4/10 | 3/10 |
It's a closely fought contest. The 1961 Triumph TR4 IRS brings more power, greater rarity, stronger collectibility to the table, and the 1975 Triumph TR7 Drophead answers with quicker acceleration, better value. Both are excellent machines that reward their owners in different ways — there's no wrong answer here.
Triumph has long offered a diverse lineup, and comparing the 1961 Triumph TR4 IRS with the 1975 Triumph TR7 Drophead highlights the breadth of the marque's engineering philosophy. On paper, the two are remarkably close in power output, with the 1961 Triumph TR4 IRS producing 104 hp and the 1975 Triumph TR7 Drophead delivering 92 hp. Under the hood, the contrast is notable: the Triumph TR4 uses a Inline-4 OHV displacing 2,138 cc, while the Triumph TR7 relies on a Inline-4 OHC with 1,998 cc. In the sprint to 60 mph, the 1975 Triumph TR7 Drophead edges ahead at 9.1 seconds versus 10.9 seconds. Rarity plays a significant role here — with only 28,465 units built, the 1961 Triumph TR4 IRS is considerably scarcer than the Triumph TR7's 112,368 examples. On the collector market, the 1961 Triumph TR4 IRS commands a significant premium over the 1975 Triumph TR7 Drophead, reflecting differences in prestige and rarity. From a collectibility standpoint, the 1961 Triumph TR4 IRS rates higher among enthusiasts and auction houses.