Can anyone identify this swingarm for me

[Gameover]

Hi

I just bought this 250R and the man that sold it to me was kind of limited on info , he was in his mid 60's and didn't seem to be in the best of health . i don't think he ever rode it , what hs said is he has had it for a little over a year and the info he id gave me he had written on some paper from the previous owner . and this is what was on the paper

8 inch extended swing arm, 38mm carb, ported and polished reed valve, Duncan ported and polished 310cc top end with Turbo Head, the cylinder is tapped for a vacuum fitting to run a fuel pump if you want to run alcohol .
The rear suspension was recently torn completely down and all o-rings, bearings, seals were serviced or replaced. new sprockets and a gold x-ring chain.installed , has an Eibach rear spring and the rear shock was recently disassembled and serviced . keep in mind this was all done over a year ago even though it has been stored since

So i have a couple questions actually first i am wondering if anyone knows who the manufacture of the swing arm is ? second question is if this motor has what he says or rather what was written on the paper then i am thinking that it would need to run hi octane fuel rather then pump gas 91 octane . i did put some pump fuel in when i got it home and ran it for a minute just to make sure it would fire up which it did but i don't want to hurt the motor and i don't know much about this kind of stuff , so would it be ok to run 91 octane or no ? and the only way to find out what has been done to this motor would be to tear in to it , Right? . so heres a couple pics of the swingarm

Thanks

[tecat-z]

Check cylinder PSI'S to help on determining what type of fuel to run. Swingarm looks like a nice late model aftermarket stretch. Not an original old school. Who cares, its's nice and gives your R a nice look. Enjoy.

[Gameover]

Yeah i didnt figure it was an oldschool swinger but would be nice to know what it is as i am thinking taking it off and selling it and putting a factory back on it as i don't think it will be any good for the type if riding i usually do , although i haven' t ever ridden with anything that long before and haven't ridden this one yet it just seems like it will not manuver as well with it being that long but maybe i'm wrong on that . i checked the compression and did it a couple times and got somewhere between 198 199 psi , that's alittle high compared to my other two R's but is that emough to need to run hegher octane ?

[viper]

i would be interested in the swingarm if its a 86 setup

[Bryan Raffa]

looks like a PRP swinger

[200x newby]

ill trade you my stock 86 swearing for your extended swinger.