Orginal Hp for trucks

Hello!

I'm from Sweden and here have peoples imported 16 Peterbilt trucks, 1 Freightliner and 4 Kenwort W 900 perhaps more. They is forbidden use them other than as veteran because otherwise they must pay for use them. And they have different strength of horsepower. In USA it is not unusual a trucker can change engine to a stronger one. I'm a little curious because there is one Peterbilt 358 made 1968 as have 250 hp. I think this is normal. Then a Peterbilt 288 A made 1970 is as developing 320 hp. Then another Peterbilt 359 M as is made 1970 and outputting 400 hp.


A Kenwort W 900 conversion made 1961 and have 370 Hp. I think 1961, this truck cant have more than 200 hp. The truck cant have its original engine today or are I wrong?


The cause I ask is because vi is talking about these trucks and some think they are more powerful than Volvo and Scania. But I think they aren't aware peoples in USA use to change engine to a more powerful.


1961 Scania LS 75 Super had 205 hp
1962 LS 75 Super had 220 hp
1965 LS 76 Super had 240 hp
1967 LS 76 had 260 hp
1971 LBS 140 got a V8 as developed 350 hp.
1978 LB 141 outputted 385 hp.
1983 LB 145 Super gave 405 hp.

Volvo had at the same time
1961 L 499 Titan Turbo 185 hp
1964 L 495 Titan Turbo 230 hp
1965 L 49501 Titan Tiptop 250 hp
1974 G 89 330 hp
1983 the F 12 gave 385 hp.

Both Volvo and Scania use their own developed engines.

How do you guys think if you compare USA-trucks to the Swedish trucks at the same time. What was normal? 220 hp?

Kind regards
Lars-Gunnar