Hi guys, I had an LT-1 72 that I had to rebuild. The blocks are the same up to 73 I think,3970010 casting # which is a 4 bolt block(HD truck block) The stock 71 heads were the same except for the valves I 2.02 exh 1.60 stock had 1.9? I, and exh 1.58. Guide plates, springs, screw in studs, pushrods and Mech cam on LT-1. The L48 crank was Iron, LT-1 was non-Twist forged steel, cross-drilled, chamfered,full fillet radii,Tufrided to .50"(hardening) depth on rod and main journals, counter weights were lightened by knife edging( more attention was paid to Factory balancing), 'pink' Rods, TRW forged alum. -8 dome pistons(If I remember right),Steel timing gears w/ dbl roller chain(cam & crank gears) More gph fuel pump, 780 cfm d-feed single pump Vac sec holley. I don't remember the stock cam #'s, I used a perfect circle mech cam I think the #'s were 108 degrees of overlap, 314 degrees duration In & exh, .458 In lift & .468 Exh lift(those #'s are from memory from 1978). The important difference is the CC volume, 70's had 64cc heads and 71 & 72 used 76cc heads. The 70 cam was way more radical than the 71 or 72 cam, but all yielded only about 15 inches of vacume at idle, 900 rpm. All of that is old tech by today's stds. Oh, forgot Exh. Manifolds on LT-1's were said to flow better even though they looked the same as L48's and L49's and exhaust pipes were 2.5" vs 2.0". Ignition sys on 70 & 71 were TI, 72 used std dist., and 70 had different mech advance and Vac advance #'s. Oh forgot all LT-1's had high volume oil pumpsTRW I think and the early production 70 LT-1's had a racing oil pan(5qts in pan + 1 in filter) hence no P/S, 71 & 72 had stock 4 qt pans, all had windage trays, but the 5 qt pan had trap door baffles front to back and a spiral baffle for side to side oil control. It was a well built S/B for the day, but now it is just nostalgic- but powerful and it sounds nice especially through factory side pipes! I'm sure I forgot a few things I did this from memory, as I sold the car a long time ago. You can make an LT-1 motor out of any 3970010 block though with enough $, modern technology has made the LT-1's obsolete(but I still want one). tt72
