Hi Harold,

Thanks once again for all your help. I'm still analysing (over analysing, perhaps) which of the UD solid grinds you've suggested that I want to go with in my 9.5:1 (ish) 408 BBC, either the 264 or the 272. Specifically:

02-UF14-UF14-10(or 12)-A01 or 02-UF15-UF15-10 (or 12)-A01

Existing cam is a HDY on a 112 LCA. All the numbers @.050 are: Dur In = 214, Ex = 224. Lift In = .501, Ex = .527. BTC = 0, ABC = 34, BBC = 49, ATC = -5.

I'd like to get the valve timing numbers @ .050 of the 264 and 272 so I can use Pat's DCR calc to compare all 3 of these cams.

Many, many thanks Harold.

Dan

Dan, when you use the DCR calculator, be sure to use advertised duration (preferably taken at .004" tappet lift). .050" dur will give you the wrong answer. Valve timing @ .050" has no useful value. I don't know why it is even speced.

Thanks Pat.

I posted the request before I dl'd the DCR calc, read the FAQ's, and started playing with it - using the numbers from my existing cam for input. It was then I realized the error of my ways.

Unfortunately, some of the hard numbers I need I just don't have; head gasket thickness and bore size, actual head chamber CC's (they are the 702 BB heads and are generally listed as 96.5 CC's), and how far in the hole the pistons are. Neither the heads nor the decks have been surfaced.

But if I make some assumptions, gasket thickness and bore of .039 and 4.370 (standard Felpro size), pistons down .020, piston dome of +21 cc's, and chamber volumn of 100 cc's, I come up with a static comp of nearly 9.9:1 and a quench of .059. I've also read that standard replacement pistons typically have the pin raised .020, thereby placing the piston down another .020. If I run the numbers like that, static comp drops to 9.5 but the quench opens to a wide .079.

Looks like I'm going to need to dig into the engine a little deeper than I wanted to!

Dan

Dan,

Here are the numbers, both at .020 and .050.
Cam/LSA BTDC ABDC BBDC ATDC BTDC ABDC BBDC ATDC
264/110 25 59 65 19 10 42 50 2
264/112 23 61 67 17 8 44 52 0
272/110 29 63 69 23 13 45 53 5
272/112 27 65 71 21 11 47 55 3
Obviously, the 1st set are at .020, the 2nd set at .050. As Pat says, the .020 numbers give a more accurate reading.
Good Luck!

UDHarold