SYSTEM

I use the following to look for a PPC.

LOCAL FN SpeedControl 'Function to change delay time based upon processor
  machType$=STR#(-16395,SYSTEM(_machType))
  LONG IF machType$ = " Power Macintosh"
    gslowSys = _False
  XELSE
    gslowSys = _True
  END IF
END FN

Don't remember what I said there! Here's some code I found, that's a bit outdated, originally (10/31/96) from MorrDesign; if everyone who gets an "unknown Mac type" from running it would email me their results and "real" Mac type, I'll update the list.

gestaltResponse&=FN GESTALT(_gestaltMachineType)
PRINT "Machine Type (_gestaltMachineType) ";
SELECT gestaltResponse&
  CASE 1
    PRINT "Classic";
  CASE 2
    PRINT "XL";
  CASE 3
    PRINT "Macintosh 512K enhanced";
  CASE 4
    PRINT "Macintosh Plus";
  CASE 5
    PRINT "Macintosh SE";
  CASE 6
    PRINT "Macintosh II";
  CASE 7
    PRINT "Macintosh IIx";
  CASE 8
    PRINT "Macintosh IIcx";
  CASE 9
    PRINT "Macintosh SE/30";
  CASE 10
    PRINT "Macintosh Portable";
  CASE 11
    PRINT "Macintosh IIci";
  CASE 13
    PRINT "Macintosh IIfx";
  CASE 17
    PRINT "MacClassic";
  CASE 18
    PRINT "IIsi";
  CASE 19
    PRINT "Macintosh LC";
  CASE 20
    PRINT "Quadra 900";
  CASE 21
    PRINT "PowerBook 170";
  CASE 22
    PRINT "Quadra 700";
  CASE 23
    PRINT "Classic II";
  CASE 24
    PRINT "PowerBook 100";
  CASE 25
    PRINT "PowerBook 140";
  CASE 26
    PRINT "Quadra 950";
  CASE 27
    PRINT "LCIII";
  CASE 29
    PRINT "Power Book Duo 210";
  CASE 30
    PRINT "Centris 650";
  CASE 32
    PRINT "PowerBook Duo 230";
  CASE 33
    PRINT "PowerBook 180";
  CASE 34
    PRINT "PowerBook 160";
  CASE 35
    PRINT "Quadra 800";
  CASE 37
    PRINT "LCII";
  CASE 39
    PRINT "PowerBook Duo 250";
  CASE 44
    PRINT "IIvi";
  CASE 45
    PRINT "Performa 600";
  CASE 48
    PRINT "IIvx";
  CASE 49
    PRINT "Mac Color Classic";
  CASE 50
    PRINT "PowerBook 165c";
  CASE 52
    PRINT "Centris 610";
  CASE 53
    PRINT "Quadra 610";
  CASE 54
    PRINT "PowerBook 145";
  CASE 55
    PRINT "PowerMac 8100 / 100";
  CASE 56
    PRINT "LC520";
  CASE 58
    PRINT "PowerComputing PowerBase 200";
  CASE 60
    PRINT "Centris 660AV";
  CASE 71
    PRINT "PowerBook 180c";
  CASE 77
    PRINT "PowerBook Duo 270c";
  CASE 78
    PRINT "Quadra 840AV";
  CASE 84
    PRINT "PowerBook 165";
  CASE 88
    PRINT "Mac TV";
  CASE 89
    PRINT "LC 475";
  CASE 92
    PRINT "LC 575";
  CASE 94
    PRINT "Quadra 605";
  CASE 65
    PRINT "PowerMac 8100/80";
  CASE 75
    PRINT "PowerMac 6100/60";
  CASE 112
    PRINT "PowerMac 7100/66";
  CASE 69
    PRINT "PowerMac 8500/120";
  CASE 67
    PRINT "PowerMac 9500/120";
  CASE 306
    PRINT "Powerbook 3400c/240";
  CASE 510
    PRINT "PowerMac G3";
  CASE ELSE
    PRINT "unknown Macintosh";
END SELECT
PRINT gestaltResponse&