Camshaft Degreeing

[JimNolan]

I need some advice here.
I installed a cam in my 410ci build back in 2012. I had a cam made for it that said 110 LSA / 108 ICL if I installed it dot to dot. I installed it on a 106 ICL. In 2016 I took the engine out of the car and installed a @320hp 390 but now after missing the 410ci,  I'm putting it back into the car.
Now here comes the juicy part. Looking at the cam card and figuring (IVO/IVC/EVO/EVC) along with @.050 duration and advertised duration I really had a cam that had a 112.3 LSA and 107 ICL. I called the cam manufacture and he said what I figured was right. He said "just install it dot to dot, you'll be OK". MY QUESTION IS THIS: Knowing I got a cam with 5.3 advance built into it, would I be better off retarding the cam 2 degrees. Lord knows I ain't going to tear the engine apart to dial it in but my crank timing gear is adjustable by two degree increments. That way the cam would be advanced 3.3 degrees instead of 5.3. Also it'll give me more horsepower on top end and the way my tires go up in smoke I wouldn't miss less torque on bottom end. Thanks everyone.

[plovett]

My opinion is that 2 degrees is a small difference and probably not worth taking the front of the engine apart for.  It'd probably be better to work on traction to try to harness the low end power you have.  I think you'd be hard pressed to feel the difference of two degrees.  If it has lots of low end now, I think it still will if you retard the cam 2 degrees.

I once had a street engine that had the cam on a 103 ICL with a 108 LSA.  5 degrees advanced.  The cranking compression was something like 205 psi.  I can't remember exactly.  I retarded the cam back to a 107 ICL to reduce the cranking compression because I was worried about it detonating on pump gas.  Again, I can't remember exactly but I think the cranking compression dropped to around 185 psi which made me feel better.  It ran great, too. 

On the other hand if you're going to put this engine on the dyno, or quantitatively test the different ICL's then by all means go for it.  Otherwise I think it's going to be hard to tell.

JMO,

paulie

[JimNolan]

Paulie, I'm at 112.3/105 now. Actually I'm talking about making it 112.3/109. A 4 degree retard from what it is now.

[blykins]

My vote is to leave it alone too.

Retarding the cam timing doesn’t always make more hp up top, nor does it always take power away from the bottom.

Advanced cam timing can make the engine pull harder on the carburetor and can improve horsepower everywhere.  Just depends on the overall combo and you’d prob need a dyno or race track to find out.

[JimNolan]

OK, I'm going to put it back to dot to dot. That'll be 112.3/107. I just never heard of a cam with a 5.3 advance built into it.

[blykins]

If you put the valve events into a valve event calculator, then you will get oddball numbers like that to the tenth of a degree.

I have cams ground with anywhere from 1 degree to 8 degrees of advance, so a 5 degree advance really doesn’t seem odd to me.

[JimNolan]

Glad to know that. All I've ever seen is off the shelf type cams. I feel better now. Thanks

[shady]

Remember also that you will probably get a degree or two retard with chain stretch & wear.