I'm about to install the S&S 97 inch big bore kit in my 2006 Softail. The bike already has 510 gear driven cams in it now. My question is how would the 510Gs work with the 97 big bore with stock heads? Or, should I upgrade to either the 558s or 583s. I'm really not looking to burn up the highway, but just have the extra power when I need it.

 

What is your projected compression ratio? The .510's like about 9.4:1 to 9.7:1 to really run well. If you want to get a bit more out of your .510's, you can also put 1.725:1 ratio rockers on the intakes only, it'll give them a little more lift. I run the .510 gear driven cams with the 97" big block kit and S&S 89cc heads with the 1.725 rockers on the intakes. I dyno'd at 105hp and 109 ft/lbs of torque.

 

Andrews 37's set at 9.8-9.9:0 cr will have more torque coming to peak than the .510's.
Wood 6's will have even more at 10.1:1 and both will fit under the OE spring.
IF, looking for more low-mid, then consider a Wood TW-5.
Those will require a spring.
Scott

 

The heads are off; the real decision to make is whether to port them or not. As Scott points out, there are a variety of cams that you could consider with head work; just a matter of selecting the cam set and having the heads set up to provide the compression "sweet spot" for the selected cam. Another consideration is the limitation of the OEM heads. Even with the improve flow of the '06 heads, flow flattens out above .500" lift, cams with higher lifts, like the 583 are not fully optimized with OEM heads. However, that said, if headwork is in the future, there is some performance to be gained then. I believe the cam the OP has referred to as the S&S 558 is actually the 557. As a direct answer to the OP's question, 86 the 510 cams and install the 583EG; gear drive easy start. Get the heads worked for the cams now or at some point in the future.

On the other hand, if you are not planning on investing on head work and the OP is just looking for a cam only upgrade, the Andrews 48 is a decent choice. True that the heads will not take full advantage of the .550" lift, but still a good bolt in choice IMHO..

I assume a .030" head gasket will be used and the inner and outer cam bearings will also be replaced and tensioner shoes upgrade to the CYCO shoes. All the necessary hardware is available in an install kit; CYCO shoes are available on Ebay.

 

Thanks for the replies. At the moment, im on a fairly tight budget, and I'm planning on keeping my stock heads and probably install new valves, springs, and seals. S&S website sez the cr with stock heads is 9.7:1. it sounds like I should be ok for now with the 510Gs, and hopefully I can get heads ported and install different cams in the not too distant future. Still may change out the cams while its in the shop m

 

Here's another suggestion on the heads. You don't need new valves unless they are damaged and the OEM springs are fine for the 510 cams. Spend the valve and spring money on a good SERDI multi angle valve job, have about .015"-.020" shaved off the heads and new guide seals. Use a .030" MLS head gasket. The added compression from shaving the heads will help the 510 cams and the multi angle valve job will help the head flow. Compression is your friend.

 

"510: Designed as a bolt-in cam for 88, 95, and 96 CID engines with compression ratios below 9.7:1, it is primarily intended for use with stock, un-ported heads. 3000-5500 rpm."


This is from S&S. They designed this as their most aggressive cam for stock heads. You want your cams and heads to match. If your budget doesn't have room for head porting right now, then keep the .510's. You might find that you like them with the added compression and cylinder volume. And if you're still not happy, put the money that you saved towards a future head/cam change.

 

We use/purchase S&S products almost every day/every other day here, after week, after month, after year, 6 days a week.
Great products that we know, VERY WELL.
That is the reason for my suggestion.
And yes, as djl has pointed out, what we refer to here as a "super-stock" valve job performed with Serdi pre-established seat angle on a single bit cutter here, or via other methods, will out-perform the OE head, using the OE valves.
Scott

 

Every cam manufacturer is going to suggest a "safe" compression ratio for any given cam. However, dyno test after dyno test have proven that increasing CCP beyond manufacturer's recommendation and within reasonable limits will enhance the performance of any given cam set. If the OP maintains stock head chamber volume (let's assume 85cc) and 9.7 CR (actually it calculates to 9.57 with a .030 and allowing an average .004" for deck height) CCP will be about 183psi. Cut the heads to reduce chamber volume to 82cc and CR moves up to about 9.8 and CCP moves up to just below 190psi; very conservative still. Combine the added compression with a "super stock" valve job and the OP is looking at an easy 5-8TQ/HP more for very little cash.

A lot of guys don't understand that the HP/TQ increase gained from a cam install is the result of setting corrected CR at 9.3-9.6 and CCP between 185-190psi both of which are functions of the timing of the intake valve close event and attribute the HP/TQ increase 100% to the cams when the increased compression is a major contributor to the gain. The 510 cam as an intake close of 38* which is what one must work with to decide where to set chamber volume to achieve optimum compression for the build. Another added benefit of decking the heads is the chambers must be measured and equalized which makes for a smoother running engine.

I don't know how much the OP was going to spend for new valves and springs and the labor to install but I would bet for a little more, he can have the heads "street" ported. He would be missing out not to pursue that option.

 

Update: The shop called and said the heads were in rough shape and needed rebuilding or replaced. I wanted to use S&S 79cc heads, but they require S&S rocker boxes, so I opted to use screamin eagle ported heads. So should I
Still keep the 510s or would the Andrews 37s (or maybe something else) be a better option. I would prefer to have more power at low and mid range than have it on the top end.