I have a coworker with a 66 Skylark Convertible. It has a Buick 350 installed in it and he asked if I could help ID the engine. The intake casting number is 1231924 - 1970 350 4bbl. The carb is 7043240 - 1973. The block should be stamped on the front driver's side just below the head mounting surface, correct? There's nothing there. Also, where the usual code is stamped between the #1 & #3 plugs doesn't have a letter combo, it just has "350". Could this be a factory service block? Any thoughts? He doesn't want me to pull the valve covers to get the casting number off the heads unless we absolutely have to. Also, where would I find the casting number on the left side exhaust manifold? Thanks!
Greg, There is alot of confusion on this subject. What you need is the 2 letter production code. It is stamped into the DECK SURFACE, between the #1 and #3 sparkplugs. That area gets pretty dirty, so at minumum, you need to clean it really well to see the letters. That part of the deck is visible between the plugs and the exhaust manifold. If the motor has been rebuilt, and the deck has been refinished to clean it up, the letters are gone. Casting #'s may not tell you anything beyond the year of the part. In 1970, the hot 350 was SP, it had 10.25:1` compression, and 315 HP, with 410 lb. ft. of torque. The SB motor had 9:1 (285/375), and the SO motor was the 2bbl with 9:1 (230/360) Remember, it's on the deck surface. The surface the heads bolt to. BTW, 7043240 is a 455 Q-jet, so the carb is wrong for an unmodified 350
Greg, I have 2 350 motors(70and72) that do not have any numbers stamped on the front of the block or any codes on the deck surface.I have looked at the blocks everywhere and see no numbers.I know the 70 motor is a 70 due to that it has never been apart and the head cast numbers and intake are 70 pieces.The 72 motor is the same and has not been apart.I am not sure about whether or not the engines are replacements or what.As what Larry said,the heads were the same cast number with the 315 hp as well as the other lower compression motors,so that will not be a way to see whether its a 315 hp engine.It will tell you the year of the heads though.I would talk your buddy into ripping off the valve covers to see what the head numbers are.Besides,it wouldn't hurt to put fresh gaskets on anyways.They probably could stand to be replaced and they aren't that hard to do or that expensive either. Pat
Thanks guys The block deck surface is where the "350" is stamped. That's part of what confused me - never heard of a cid indication being stamped there. He's not as concerned about which 350 it is as far as horsepower ratings, just what year. He wants to be able to include that information when he tries to sell the car. The carb being for a 455 is interesting - I need one. :grin:
