I'm looking at bolting on an S&S 106" kit to my 96" softail using the 54H cams and stock heads....

1. What compression ratio do these cams like?
2. what will I have to do to my heads to get there?
3. I don't want to do any headwork if possible.

Appreciate any help with this one, or suggestions of a different cam?

 

If you can call us later today, we can push that combo through one of our engine programs, and tell you spot-on, where it wants to be.
Scott

 

Just about anybody can look into the heads and see where some improvement will help.
Same with the TB.

I don't mean big stuff, just a little smoothing here and there.

I would think about some, at least a little, headwork because the engine will like it better. You will already be doing a lot of work anyway and the heads are the most important part of how well an engine does its job..

These guys can give several options I bet and good options and still not be at all ratical.

 

Scott's engine program will produce more definitive results than my "seat of the pants" approach but the below should get you in the ballpark.

I don't know what CR the 54 cams like; back into the static CR using corrected CR and/or cranking compression. You may find some disagreement on this subject; however, for my purposes and for my motorcycles, a corrected compression of about 9.3 and a cranking compression of about 190psi is a reasonable target for a well mannered street build.

Roughly speaking, your stock heads and 0.00" deck height (which you probably don't have) would need to be decked to a chamber volume of about 84.5cc; or .010"-.015", more or less, depending on the original chamber volume. The stock chamber volume should be 85-86cc but I have seen some as high as 89cc. In that configuation, your static CR will be 10.2; corrected 9.3 and cranking 193psi and that would work for me.

I know you say you don't want to do any headwork but if you are going to the trouble and expense to improve performance and the heads have to be machined anyway, why not some headwork? At least a proper multi-angle valve job and new guide seals??

I like the dynos I have seen for the 54 but have never run one. I am also partial to the Andrews family of cams. The 54 was only introduced early last year and was touted as a cam designed for the 96" motor. From what I have seen, the 54 is better suited for the larger displacement motors, from 103" and up. It should work will in your application but you will hear from the proponents of the TMan camp (also one of my favorites as I have run several), the HQ camp and the Woods camp but at the end of the day, you will have to decide.

 

Yeah, thats good advice. Doing an engine build is more or less like an "all or nothing" kinda deal..... If you leave one ingredient out it ruins the recipe...

 

If this were the case, wouldn't most guys with 96" motors just do heads and cams???

 

Thanks djl, thats great advice. A lot to think about.

 

Thanks Scott, will do. Whatever it is I think its going to be more than the compression I would get from just using stock heads.

 

I had my heads set at 86cc. I use a .040 head gasket. I get mid 180s ccp. BigBoyz says
it would be 185ccp. Only thing is my deck height came to .003 out of the hole.

I HAVE a 106 with andrews 54 build and really like it.

When apart... if the pistons are a teeny bit in the hole... run .030 headgaskets. If a teeny bit out of the hole... run .040 headgaskets.

You will be fine and you have enough compression for this set up.

 

And if you have use of a fax machine, we'll fire over the entire data sheet for that type of build.
Scott