[mikep]

Minor points really but those heads are not LT-1 heads. 487's are decent castings but theyre not what came on LT-1's. LT-1's had 462's with 64 cc chambers and 2.02 intakes and 1.6 inch exhausts. They also came with screw in studs and straight guideplates. The ports were a little bit larger than 487's as well. The 350 LT-1 being sort of the high water mark of muscle car small block development. There werent many of them so don't feel bad . Not that any of that makes any difference but its nice to know what you have. 487's were the standard LoPo cylinder head with 76 cc chambers and small valves up to 74 I believe. That means that with that edelbrock RPM ( or clone thereof ) cam you are using you will not work well with your combination as you are too low on you compression with those flat top pistons. You can get away with a cam that big in a heavy truck if you have enough compression to back it up but in your case your'e too heavy and your compression is too low. You'd have a dog in the waiting. For your compression ( 8.5:1 or so ) and intake with those heads I'd say any more than 240 or so on the duration would be too much . Most people say less duration is better for trucks but I think thats a bunch of hooey although a summit 1102 or edelbrock performer will put you in the 340 HP region with 380+ ft lbs of torque but you'd have no idle lope. Yes, that is important! The cam I like for overall stock motors such as yours with a dual plane intake and a set of headers is the competition cams copy of the old L-79 cam. Its got a 229/236 duration spread with .468/.462 on the lift which puts your peak torque right at 3500 rpm. Perfect for a heavy street truck. I ran it through the desktop dyno and came up with 326 HP at 5000 rpm with a fairly flat curve from 4500-6000 . Torque would be in the 364 ft lbs area at 4000 but its flat as a board from 3000-5000.
With the RPM cam you loose about 20 HP but worse than that your torque takes a nosedive to about 300 ft lbs. Bigger isnt always better in cam selection unless you have the compression and porting to back it up.