Weakness of the 80" is compression and emission based design, the 80" can have alot done to it but with stock heads you are limited. Stock Harley heads are great candidates for performance work, $600 to have them done, piston change to get around 9.8-1, the Ev27 or a Vthunder series cam will do fine, if more lift is your game then the Vt5005 or Woods W6h will help the reworked heads breath a little better. 80hp-80tq is very reachable with a 80" Evo and $1200 should be a safe budget if you tackle the parts swapping yourself or go big and accellerate like your hair is on fire, either way, we will spend your money.

Something else that is a big help on a large barge is to drop the primary gearing to 3.34 along with the engine work and you will be happy with the outcome, giddy up!

 

What he said !

 

That sounds like more what I am after. If my engine was on it's last legs or something real bad happened to it, I would be all over the Ultima drop in 127 at $4K. But, I think maybe more compression along with the cam would be a good idea. I am not afraid of tackling the engine work, and that dollar amount is more in line with what I was thinking.

 

This page will give you a few things to think about

http://www.woodcarbs.com/dynoruns.htm

 

Oh yeah - more options rolling around in my head.

What is the opinion on increasing compression - shave the heads or replace the pistons?

 

I have the same bike, year and engine, and just just finished a total top end build and the bike SCOOTS. Goes up hills now in sixth gear, and in fact that is one of the changes I would recommend.
Here are the particulars of the build. CV carb sent to Killer Motorcycles, came back rejetted and bike runs super. Revtech overdrive six speed transmission. Stock heads with new valves, replaced one guide, the others good. Wiseco 10.1 pistons .010 over. Cometic .050 head gasket, and cometic base cylinder gasket. Andrews EV27 cam. New JIMS lifters, and Andrews Aluminum hardened pushrods (lighter and revs faster). You can keep all stock valve train geometry with this set up, and my clutch still works great. I can not tell you what a difference this build has made in the bike's performance. I have Vance and Hine Long shots with baffles and the bike also sounds superb. Build the engine you have. Great learning experience, inexpensive compared to a new engine, and numbers matching.

 

I personally think it is better to get different pistons, it takes 72 cc's and a .030 head gasket to get around the 9.8-1 range with stock pistons, which is taking a good amount off the bottom but is doable. Bolt in 10-1 like Jethro mentioned is an option or a 9.5-1 and have a professional set up your compression with a squish of .030 with the chamber volume is more a perfection set up. Heads reworked with some port clean up with a larger intake valve is usually basic and complements the higher compression ratio and the best money spent which is explained in the next paragraph.

Every engine part on a Evo needs to be a match to get optimal results, from my mistakes, it is best to have a GOOD engine/head guy to guide an engine build, had a well known engine builder do my heads and stayed with me through my build and shared some knowledge along the way, John (Mia) and many on this board will also provide some good tips on directions and end with I thought I knew alot about engines until I met someone that knew alot about Evo engines, my lesson on help from a Harley Engine Guru "shut up and listen weedhopper"

 

So you didn't go with any extra work on the head? Just freshened up? I was wondering about trying to find a good source for maybe some porting if I was going to have them off anyway. I am not sure what the gains will be at this level with porting but I would like to know. I looked at S&S heads but it seems they are real proud of them and I would kinda like to keep my own anyway. I have done plenty of engine work in the past, and I always said every older engine gets to the 'may as well' stage. Never sure where to draw the line with the mods and tear down. Gonna do the cam, probably should look at the heads, gonna have the heads off anyway, may as well port them. As long as the heads are off, I am right there to take the jugs off, on and on.

 

Call John Sachs in Florida and get him to do your heads. You won't be disapointed. He ca also give you some help in getting sarted in the right direction for the best results.

 

Yeah, I agree with the finding of the guru. I would really like to do the teardown and reassembly, but know nothing of the black art of porting - I would like to find someone nearby to do the head work and give me some pointers on the remainder of the parts. I saw some cylinder head guys at the local Donnie Smith show, but I ran out of time to talk to them. (I really wasn't considering pulling the heads at that time)