Most people around here with Chevy's of that size run 76mm's or 88mm's
Here are some pics of a Challenger w/ a 500 Stroker and GT-47(88mm) turbo... the power is amazing at 10.5 #'s of boost.
Specifications:
Block: Factory Chrysler RB 440
Crankshaft: Eagle 4.15
Rods: Eagle H Beam
Pistons: Ross
Compression: 9.2
Heads: Edelbrock Performer RPM 88cc
Intake: Edelbrock Performer RPM
Cam: Comp solid roller
224/230 @.050, .577/.590, 114 LSA
Throttle Body: Accufab 80mm
Turbo: Garrett GT47-88, .96 A/R
Wastegate: HKS GT-II 60mm
Boost: 10.5 PSI
Exhaust: 5-inch downpipe, dual 3-inch, Magnaflows
Rear Wheel Dyno Numbers:
RPM RWHP RWTQ PSI MPH SEC
---- ------ ------ ---- ----- ----
1893 133.5 370.3 0.0 43.5 0.2
1951 143.8 387.0 0.1 44.5 0.3
2010 159.0 415.5 0.2 45.8 0.4
2063 170.4 433.7 0.3 46.9 0.5
2121 179.9 445.4 0.3 48.1 0.6
2175 187.9 453.8 0.4 49.2 0.7
2227 194.3 458.3 0.4 50.4 0.8
2279 202.0 465.6 0.5 51.6 0.9
2326 209.3 472.5 0.6 52.8 1.0
2382 216.4 477.1 0.7 54.0 1.1
2447 223.6 479.9 0.9 55.2 1.2
2500 232.7 488.9 1.0 56.6 1.3
2560 240.9 494.3 1.2 57.9 1.4
2620 250.0 501.1 1.3 59.3 1.5
2684 259.8 508.3 1.5 60.6 1.6
2742 272.8 522.4 1.9 61.9 1.7
2794 285.4 536.5 2.2 63.5 1.8
2881 298.5 544.2 2.5 65.0 1.9
2958 316.5 562.0 2.8 66.7 2.0
3027 332.0 576.0 3.3 68.2 2.1
3103 353.9 598.9 3.7 69.9 2.2
3186 378.7 624.2 4.1 71.7 2.3
3272 398.8 640.2 4.8 73.4 2.4
3359 425.7 665.6 5.3 75.4 2.5
3445 454.0 692.1 5.9 77.4 2.6
3538 482.5 716.2 6.5 79.3 2.7
3647 514.0 740.2 6.9 81.4 2.8
3751 547.5 766.6 7.4 83.6 2.9
3847 587.7 802.3 8.0 85.6 3.0
3946 618.8 823.8 8.3 87.8 3.1
4068 644.8 832.4 8.4 89.9 3.2
4166 668.5 842.7 8.6 92.2 3.3
4247 692.8 856.7 8.9 94.5 3.4
4339 720.2 871.6 9.1 96.7 3.5
4461 737.7 868.5 9.4 98.7 3.6
4545 751.4 868.4 9.6 101.0 3.7
4615 760.4 865.4 9.8 103.2 3.8
4725 765.0 850.2 9.9 105.2 3.9
4812 770.4 840.9 9.9 107.4 4.0
4914 779.5 833.1 10.1 109.5 4.1
4969 790.4 835.4 10.3 111.6 4.2
5046 798.4 830.9 10.5 113.5 4.3
5140 806.8 824.4 10.5 115.5 4.4
5239 814.0 816.1 10.5 117.5 4.5
5326 817.8 806.4 10.5 119.4 4.6
5411 825.4 801.1 10.5 121.4 4.7
5498 830.7 793.6 10.5 123.3 4.8
5585 835.4 785.6 10.5 125.2 4.9
5651 838.5 779.3 10.5 127.2 5.0
5716 838.8 770.7 10.5 128.9 5.1
5827 837.9 755.2 10.5 130.8 5.2
5858 833.6 747.4 10.5 132.6 5.3
5597 790.5 741.7 10.5 133.0 5.3
**Sorry for making such a long post.. thought you might interested though.