TOPIC: changing 60hp looper for a 70hp looper

I'm not sure if a 60hp looper power head will change with a 70hp power head. Will it work?
Mike aka the pirate

As long as they are the same displacement (49ci or 56ci) the answer is yes

I did forget to say they are both 1970s
and thanks
Mike aka the pirate

No, they will not swap - assuming they are 1970s era. The 1970 60hp triple is quite different from the 1974 & up 70hp triples, particularly in the exhaust area on the cylinder. That, in turn, makes the mid-section and exhaust tuner diffferent. They also have different ignitions systems, and the 60hp would be electric shift while the 70 is hydromechanical or straight mechanical (depending on year).

If they are late 1980s 60hp and 70hp models (both 56 cubers) then yes, they will swap...

Mike - I'm glad you asked this question - because I want to upgrade a 1969 55 Triumph shorty. I'm on the low end of the learning curve with these loopers still.
Scott and or Prof.. - OK, I've got the 55 triumph and it's a shorty - which is almost impossible to find around here. You've both informed me that the 55 is a 2 port block and the pistoms were prone to failure when abused. So, what is my, and Mike's best move? If I can't drop a 75 powerhead on my shorty -what will drop on? a 65? I don't want to waste money on the 55 block if a more powerful alternative is out there. And keep in mind - I don't mind mixing up parts from various years to make a good runner. Mike - sorry if I Hijacked you - hopefully my questions help you too.

No high jack to worry about we both need info on about the same thing. Only time I might upset is if it goes off on to something else completly.
My friend has the 60 looper and a nice looking motor but a bad cyc and I have 70hp that looks like hell but runs. And that is the reason for the question.
Nike aka the pirate

Mike,
As with most things, you could probably make it work with an appropriate injection of time and money. The 70hp adapter plate might bolt up to the shorty mid in place of the 55 plate. That would eliminate the powerhead to adapter issue. I'm not sure if the old 55 has a fine spline or 4-sided driveshaft at the top. I it is different from the 70 (4-spline) then you could mod the shaft to accommodate it. Then there's the exhaust tuner - I'm not sure how you'd mod that - maybe just cut the one from the 70 short? Or maybe take 5-inches out of the middle and weld it back together? The 55's tuner is noticeably smaller in diameter and would restrict the 70.
Bottom line - it wouldn't be a bolt up swap... but could be done with some mods and ingenuity.
- Scott

3 cylinder loopers all had the same crank spline ( coarse 4 spline ) to about 88 then they went to a " fine spline " from 89 on.