My DC-19 cams are closer to the 20/21 specs than the DC20 cams. My DC19's might give a little more clearance than the 20/21's at overlap.. mine are ground on a 113 LSA, and I think the 20/21's are on a 112?

2.1 mm on the DC20 cams put the cams in advanced, just not as advanced as the 2.2-2.4mm spec. (within a degree)

THanks for the correction John. Blind assumption on my part- DC20, 20/21, they both have 20 in them so should be similar.... duh.

I was only able to get my cams at 1.85 on the right 4-6 bank. Other 1-3 bank had comfortable clearance at 2.0mm but I wanted both banks to be the same. Down the road hopefully the Euro 10.3:1 pistons allow for more clearance. How are these compared to 9.3:1 pistons? Pocketed or no?

hot rod rule of thumb
 

"ain't no replacement for displacement" is the hot rodders' rule

they(we)'ll also confirm that mucking around with cams & peripheral top end parts usually just results in crummy driveability,

but if you keep your foot on the floor all the time & the engine wound up high, you won't ever notice that problem

I think most of the info on my build is posted on here if you search my name but the short answer is that I started with a euro 89 3.2 and added 993 Supercup cams and SSIs. Also 993 rod bolts, head studs, race valve springs, Ti retainers, valve job and some sundries. Once a small problem with the machine work was ID'd and fixed it made 260hp (flywheel hp on an Aussie Dyno Dynamics rolling road).

My engine builder said piston to valve clearance with these cams was fine without any machining to the pistons. I run a 6800rpm redline as the top end is good for much more and the bottom end should be good for the same as a 993. The Supercup cams make good hp up to about 6600rpm in my engine before starting to drop off. Even at the limiter they are pulling hard though. A 7000rpm limit is tempting :)

I am now on 993 HEs and should be making more hp but I haven't retested and the dyno place has closed. The std intake also leaves a few hp on the table. I am reluctant to pay for extrudehoning (which seems like a bandaid) when I want ITBs long term. Some tuners like the late 964 plastic intake which can be made to work and is supposed to be good for a few hp over the 3.2 intake.

Jeremy is right about the cake analogy. The engine is a system and you can get some results from changing one thing alone but the synergies don't come until you enhance/improve everything. To get to 280hp from a stockish 3.2 would be tricky. I think Steve Wong has mapped some 3.2 race engines to make this kind of power but they are running race gas and lots of timing advance. Otherwise carbs/ITBs are probably the order of the day.

RB