96" and 103" barrels can be bored out to fit 107" pistons (3.937" bore size from memory), not 100% sure about the 88" but I think so.
I am looking at doing something similar to my 96" and have done a shitload of research on the subject.
My final??? wish list goes something like this:
bore original barrels to suit 107" high compression pistons (10.2:1),
street port and clean up the heads (using original valves) and fit manual compression releases,
true weld and balance crankshaft,
Timken bearing conversion to crankshaft,
re-balance balance shafts (it's a Softail..),
get the throttle body taken out to 50mm,
billet oil pump and Andrews 57H cams.
I'm hoping for somewhere in the region of mid to high 90's hp wise and a little over 100 ft lbs torque, when I finally get all the descisions made and parts organised a couple of months down the track..... or more??
There are several US HD forums that are an absolute wealth of information once you figure out how to sort out the shit from the clay...
Hope this helps.....


confuse you some more..

Cheers,
Chris.

Ozymax, all the stock 88", 96" & 103 cylinders will bore out to 107". The '06 & latter heads are the ones you need. The chambers are about 85 - 86cc & take 1.90" intake valves with the stock seats. Not sure if bigger seats are required for the 1.94" Intakes, but definitely larger seats for the AV&V 1.98" valves. Larger 1.61" exhaust valves will fit these heads also.

chrise1961, save your money & use a stock oil pump, which is more than up to the job, maybe a Baisley by-pass spring if you want a bit more oil pressure. - Rob

chris, I am not opening the cases and doing the crank, If I went that far it would be for a lot more than 106. I am all over the USA sites and see some of the members on them as well, Does take some working out though.

Hilly, Torque torque and more torque, and low down. 100+ from 2000rpm. HP will take care of it's self I feel.
Often ride 2 up all up 130kgs, on my own usually change up around 4800 just to keep the noise down a bit and it's quick enough at that.
Long past drags but still enjoy the feeling. If I try for 10.2 / 10.5 :1 or better I can always loos a bit with cams or HG if needed.

KiwiRob thanks at least I have a starting point for the hardware, Will be going with the larger valves I think. Just a matter of finding some that match the current cosmetics.
Several shops are showing good torque with the larger valves which I thought may not have been the case so I see no point in leaving it on the bench.

well looks like I found some heads and barrels.
and probably sending them to Kirby Apathy at Vee Twin Performance in Florida unless some has advise I shouldn't.

Cheers Hilly.
Had a brief discussion with Kirby, he is getting back with some firmer costs and ideas. 10.5:1 Woods 777, not sure about throttle body may just clean and radius mine up here. exhaust will be 2:1 current v&h slightly modded but wanting to see how the D&D Bob Cats go.
Will track down Dan and have a chat to him also.
Gotta get my times of day sorted.

Wet up your way mate

Yep got his site but they don't give the number and suggest the best way is email. maybe to stop interrupting his day. I'll send a mail and ask for his number if he prefers that way.

Hilly you know a shit load more about this stuff than me so don't be shy in offering advice.

Rain starting down here today and will only get heavier as the weekend comes on.

If I get a descent base map I will give it ago myself, other wise I''ll stick it up on the dyno and sort it from there

 you could get a 107 fuel moto kit with your choice of woods cams

I could but where's the fun in that

look at the tman stuff
http://tmanperformance.com/