Hi Guys !

I work on a project to rebuild an 1997 EVO engine and I think about to change the cylinder heads.
S&S proposes 2 options, with different combustion chamber:
- 82cc
- 76cc

Stock engine should have 80cc, 8.5:1
The 82cc, 8.4:1
The 76cc, 8.8:1

So, my question is: should I order the 82cc or the 76cc?
- What's the pro/cons of each?
- Better to have the 82cc? (the difference compared to the stock should be not noticeable)

Thanks guys for your help! :-)
Cheers,
Xavier

 

 

Hi,

Thanks for your answer!

I think that I'll use a stock cam. But maybe, adding a evl-3010 is an option.
It's have 39 intake close, but V-Thunder says that it's a bolt-in cam; that's works great with a stock engine...

About compression, I've heard a lot of different opinion. Some guys says that it's better to have more compression (more hp).
But also some other says that a low compression can be good as well (less temperature, etc.)

 

The 3010 is a very good cam.. If your going to replace the heads then go with the 76 cc heads and a .030" head gasket... That 3010 will like it better...

A good friend of mine is running that cam in his Road king. He let me ride his bike to check out a carb issue and I must say, I was very impressed with the way his bike moved out...

 

compression should be set to what cams your going to run,that said,if your going with stock cams (or even very mild cams) why get S&S heads,have mild port work done on your heads

 

Download this compression calculator:

www.nrhsperformance.com/Compression.exe

then put in the numbers and have a ball seeing what changes.

 

Thanks guys for your answers!

I'll probably go with the 76cc with a 0.030 gasket and the 3010 cam.

 

Thanks for the tip!
I usually use the online calculator here: http://bigboyzheadporting.com/EVOComp.htm
Work fine ;-)

 

Yup, that works too, and it's got most of the available cams built in!

 

Everyone has an opinion and it is a slippery slope
This is what works for me
Bathtub chamber ,
10 .5 to one dome
double plug with Daytona TT
set your squish screaming close (.030 no more)
Very light weight ring pack
DM 530 cam
it will become a tiger!