Stock 88 w/ 21's - should I deck the heads?

[KumaRide]

Installing 21's in my stock 88 with Stage 1, dealer download and BSS. I saw a recent dyno with the 21's in a 88 with the heads decked ~.038 and a .030 gasket. I bought the bike used and it has less than 5k miles. Given that, and a tight budget, it seems wasteful to do a BB. Decking the heads seems like it would cost much less and provide similar results as a BB. If I install 21's and decked heads would I notice a seat of the pants performance improvement as compared to a 21 cam install only? And, would a PC III be required with the increased compression? Several of you educated me on the BSS not being ideal for a cam build. As pipes are expensive and I do like them, they will need to stay on the bike.

[Bagger]

Have the heads cc'd and if necessary milled to achieve the desired "corrected compression ratio" with whatever gasket thickness you choose.

For example:

If your untouched heads are 88cc + TW21 + 0.030" head gasket + = approximately 8.5:1 Static CR and 8.2:1 corrected compression ratio.  My stock heads on my 2002 Road King - one was 88cc and the other 86.5cc

Now if your heads are milled for 80cc heads + 0.030" head gasket thickness + TW21 (intake close of 30 degrees)  = approximately 9.2 static CR and 8.8:1 corrected compression ratio. 

Post #23 discusses corrected compression ratio:  http://harleytechtalk.net/htt/index.php?topic=3168.20

Only you know how tight your budget is and what's it worth to you..... 

[KumaRide]

Thanks - I read that a couple times before and it makes sense. I am also looking for some confirmation if increasing the compression per the article and your calcs would make a noticeable seat of the pants improvement. Several 21 riders confirmed that the cam alone will be noticed. Read in a thread that some one installed the 21's in a 88. Then later added a .030 gasket and no performance difference was felt. Trying to get an idea of what SOP benefit decking the heads and the .030 would provide.

[Jeffd]

I did a direct comparisson in a 95 between stock hg and .030 hg and no seat of the pants difference.  I would not go to the trouble of changing hg.  Why chance pulling a cylinder stud etc for maybe 3 extra ft/lbs....oh wait 3 extra ft/lbs you would be crazy not too.  LOL.  I bet you would feel a good set of pipes vs the .030 hg. 

[blk-betty]

Just another opinion but if it were mine (and this is something I'm seriously considering) I would not touch the heads unless I was doing a BB.  If you go to the trouble of pulling the heads to deck them you might as well remove the barrels and go 95".

Do you do your own work, if so maybe not a concern other than your time but if your paying someone and money is tight do the cams alone, then if money comes in later do the heads and 95".  Bet the price for cams alone would be half to 2/3rds the cost of cams plus head removal with decking and reinstalling.

[razar]

Finished an Andrews 26 install in 03 carbed 88 RK in October.  Jetted, big sucker a/c, cycle shack slip ons.  Dyno 75 hp 89 tq, pulls good off the line and makes mamma hold on.  I'm happy and someday will go with BB and head upgrade.
Razar

[Arrowsmit]

JeffD & Blk-Betty nailed it IMO.

VicW.

[Bagger]

Yea, have to agree with the guys - leave the heads alone unless you're doing the 95" kit.  The cost is only minimal if you can take the heads off and have a local shop mill them.

[KumaRide]

I appreciate the suggestions. I will probably leave the heads alone.  Decking the heads is pretty cheap - $75. The money comes into play when a PC III is added (I am assuming a PC is required. Even a used one is $175), adj. push rods, then $40 for the .030 gasket. The labor of course is my time.

[PanHeadRed]

>I will probably leave the heads alone.<

IMO, good idea, no point in limiting your options for the future.