Hello all, I have a 2002 Dyna with 95" engine and S&S super stock heads. 79 cc chambers, 1.94" intake and 1.575 exhaust valves.

Currently running Andrews 55 cams at 10.6:1 static compression.

Does anyone have any experience with these heads, would there be any significant gain from having them ported, changing to bigger valves or such, while still at 95" displacement?

Also I'm considering going to 106" this winter using a 4.375" or 4.5" stroke crank. Would that require a different setup of the heads compared to staying at 95"

I have attached the flow numbers for the heads in their stock form.

 

Yes the heads can be ported and gains realized. Using a larger exhaust valve, 1.610 will also help on multiple fronts. There might not be big dyno number gains, but there will be driveability gains, lower engine temps and better overrall efficiency. And you wont have to change anything when you raise you displacement. Though i think there are better cam choices, but that is a personal taste situation in this case.
m

 

Try Jim at Megaflow. The right guy for those S&S super stocks

 

A good port job will probably get you up to about 285 CFM flow on the 1.94" intake.. But as Marco pointed out a bigger exhaust valve will make a nice difference.. Currently your exhaust is only flowing at 68% of your intake.. Ideal flow would be between 75-80%.. I think a Woods W-8 would out perform the Andrews..
Have you Dyno'd the bike with this setup?

 

Here's a head flow study that I believe @Max Headflow might have been involved in as noted on page 7 Carburator flow bench test with stock manifolds..
Try googling
http://neverworld.net/socalnetscum/f...BStudyRel1.pdf
I believe your heads will never reach the potential they can with the CV 42 and depending on what intake you have,If it's stock you'll never get the advertised CFM of the S&S..

 

Thanks, this is good info. I have a S&S intake manifold that is matched to the ports on the heads, 1.78" diameter. I believe it's the same intake as the Super G but machined to fit the Mikuni.
Maybe changing to a HSR 45 would be a good idea? The CV44 would be nice too but they are almost impossible to find it seems.

 

Did a bit of math, HSR42 on Super G manifold flows 252 cfm@28, and HSR45 flows 274 cfm@28.

So a HSR45 seems more in line with the heads flow, but maybe I then need a "bigger" cam to reap the gains from that?

Static comp is 10.6:1 according to big Boyz, so around 45 degrees IVC, 250-ish duration and as much lift as possible I guess. Valve springs are good for .650" lift.

 

The 45 would be a good idea and will need a new intake but my preference is the Super G. They both will allow more flow at Higher rpm. As for the cam, I suggested the W8 because It was the only cam I ever had that carried to 6500 and still making power. The midrange with that cam was also phenomenal and in a bigger bore will still have good low end street manors. I would not go with a stepped exhaust. Keep it at 1 3/4". Also, once you get over .600", you're not gaining much with the S&S heads. A .030" head gasket (cometic) is best for squish.

 

Thanks for very good info.

​​​​​A HSR45 actually fits the intake I have, it just needs a different seal. It is the same intake for CV40 and CV44 with the round rubber intake seal.

My exhaust is a S&S Grand National 2-2, 1-3/4" headers with a crossover chamber and megaphone mufflers. I think it is quite similar to stock headers with slip on mufflers.

I do have 0.030" Cometic head gaskets too.
I will keep my eyes open for a set of Woods TW8. I run gear drive now but have been considering "conversion" cams with 06+ hydraulic cam plate. I will also see if I can trade my carb for a 45 mm. Winter is long here in Scandinavia

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So

What creative math did you use?