Wow, that's awesome! I have the same year and package as yours with SWB. I starting restoring on her last Feb, 2009 till next next year... due bad weather keep coming out in 2 months on Nov and Dec... my baby still sitting under my car port and cover her. I hope the nasty weather going away very soon this month... I can't wait to painting her '99 GM Bright Blue Metallic #5215 then getting ready to put all front end back together and the bed too.

My friend put new fair idle Magnum Competition Racing Cam and kit into my new Hi Performance 355 Chevy motor and rebuilt 700R4 Over Drive trans. Next year my friend will put new 3.42 rearend gears into my '83 Silverado rearend for my baby Truckin'!

I posted Topic (Thread) about my Truck restoring starting in "Members Rides" board, check it out many information and photos. Let me know what you think and hope you like it.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=13992.0Here's my Magnum Competition Cam kit information:
ENGINE: CS 270H-10
PART #: 12-211-2 03/20/2009
GRIND NUMBER: CS 270H-10
INTAKE EHAUST
VALVE ADJUSTMENT HYD HYD
GROSS VALVE LIFT .470 .470
DURATION @
.006 TAPPET LIFT 270 270
VALVE TIMING OPEN CLOSE
@ .006 INT: 29 BTDC 61 ABDC
EXH: 69 BBDC 21 ATDC
THESE SPECS ARE FOR CAM INSTALLED
@ 106.0 INTAKE CENTER LINE
INTAKE EXHAUST
DURATION @ .050 224 224 981-16 SPRINGS REQUIRED
LOBE LIFT .3130 .3130 VALVE SPRING SPECS FURNISHED
LOBE SEPARATION 110.0 WITH SPRINGS
I'm glad to have you a new Truckin' friend with your awesome '84 GMC Sierra Classic with Hi Performance 383 Chevy into your baby Truckin', welcome to '73-'87 Chevy Trucks site!

Looking forward to hear more from you.