GitDirt.com Calculators Racing Photos Race Car Setup

GM Block Casting Numbers

Older blocks with 010 markings are a better quality of metal.
When picking a block pay close attention to the front camshaft hole.
Look for the hole to be centered in the block casting. Try to avoid blocks where the hole is offset to one side.
Casting # Year Size HP Notes
3703524 55 265 N/A Passenger
First 6 mos. used mech. cam not hyd.
3720991 56 - 57 265 N/A Truck/Pass
3731548 57 283 N/A N/A
3556519
3737739
58 - 61 283 220-290 2-Bolt mains/Truck/Pass
3849852 58 - 64 283 220-315 2-Bolt mains/Truck/Pass
3789935
3864812
62 - 64 283 230-315 2-Bolt mains/Truck/Pass
3959512 62 - 63 327 250 2-Bolt mains
3789817
3794460
62 - 64 327 250 2-Bolt mains
Truck/Pass
3858174 62 - 67 350, 327 & 302 210-350 2-Bolt mains/Truck/Pass
3782870 62 - 67 327 250-375 2-Bolt mains/Truck/Pass
3858180 62 - 67 327 250-375 2-Bolt mains/Truck/Pass
3791362 65 - 67 327 N/A 2-Bolt mains/Chevy II
3892657
3782870
3903352
3789817
64 - 67 350, 327 & 302 210-350 2-Bolt mains
Truck/Pass
3849852
3849935
3896944
393288
65 - 67 283 N/A Truck/Pass
389257 67 - 69 302 N/A 2-Bolt mains
67 Small Journal (327 block)
68-69 Large Journal (350 block)
3914653
3914636
3932373
3970020
68 - 73 307 N/A Truck/Pass
3956632 69 307 200 2-bolt mains
3914660 68 327 210-275 2-bolt mains
3790041
3814660
3955618
68 - 69 327 210-300 2-Bolt mains
Corvette/Camaro/Hi PO
3914678 68 - 79 350, 327 &: 302 210-350 2-Bolt mains
3855961
3958618
3970014
6259425
68 - 76 350 210-300 2-bolt mains
Pass.
3970014 68 - 79 350 200-255 2&4-Bolt main
3956618
3932386
68 - 79 350 & 302 250-300 4 bolt mains
Truck/Hi Perf
3970010 68 - 79 350 & 327 145-375 2&4-Bolt mains/Truck/Hi Perf
3932388 69 350 300 4-bolt mains
3951511 70 - 73 400 255-265 4 Bolt mains/HD Truck/Pass
330817 70 - 80 400 150-180 2-Bolt mains
360851 74 - 76 262 N/A Monza
3951509
3030817++
74 - 76 400 150-265 2 Bolt Mains
++High Nickel Block
460776
460777
460778
361979
78 - 79 305 N/A Lt. Truck/Pass
14016379 78 - 79 350 N/A Lt.Truck/Pass
366245* 78 - 79 350 N\A 4-Bolt mains
*Bowtie High Tin
Dipstick in Pan
1401280
14016376
471511
79 - 82 267 N/A Passenger
14010201
14016381
14010202
14010203
80 - 84 305 N/A Lt. Truck/Pass
1401029
14010207
14010209
80 - 85 350 205 & up 2&4-Bolt mains
Passenger cars
14011064* 82 - 86 350 N\A 4-Bolt mains/*Bowtie High Tin
14088548
14093638
14316379
86 - 88 350 205 & up 2&4-Bolt mains
1 piece rear main seal.