Gmc 270 Engine Serial Numbers
I pick-up a super clean '67 Chevy G-10 Van a few weeks back. Problem is, I can't I.D. If the engine is a 230 or 250. The local parts shop, and speed shop couldn't figure it out. After surfing the internet, I still can't find without 100% certainty which it is. Most sites I found list it like this, 230-250=7.
I found a thread here on the HAMB, but it doesn't solve the question. Here's a pic of the casting number that's located on the passenger side just behind the motor mount.
270 Gmc Engine Specifications
The casting number is 3877178, below that is GM, and below that is what looks like 4.7 or 4.1. I know the 230 is 3.8 litres, and the 250 is 4.1 litres. Would appreciate any assistance. Update!!!Seems we are not alone in the search for this answer.
I went a local machine shop today and dug up some juicy info. The answer didn't jump off the manual's pages, but did point us in the right direction. The 230 and 250 both have the same bore of 3.875', which by-the-way can be opened up to 4' to accept 350 pistons, but thats another story to be ventured into. The stroke on the 230 is 3.250', and for the 250 it's 3.531'.
Seems there is no external way to positively identify the difference between a 230 and 250. The magic number could be hidden behind the bell housing. I'll update this thread with that info after I pull the trany to rebuild it. Yep, blew the trany in my Van. It's a running joke with my idiot posse; ) Gotta laugh! So, without finding an external casing number somewhere on the block, the only way to know, is to get the forging number off the crank.
I'm replacing the rear main seal and oil pan gasket anyway, so when I'm there I'll rotate the crank and get the number to find my answer. Still can't believe it's so difficult to identify it. Maybe we're all missing something.
1957 Gmc 270 Engine Specs
I'm sure after all the digging and labor someone will chime-in and say, 'Oh it's right there.' Until then.I referenced the Clevite 77 catalog No.
2-200-05 for this data, as follows.250 Crank Forgings: 460407, 4914, 3876802, 3876804, 3876840, Crank forgings: 8424, 3788423, 3788424, 3788428, 3820618, 3864465, 3899424, 5743013, 9782279, 9782297. Snarl, pulled a few plugs, very difficult to see, or even get my mellon in there to see, but I'll try again in the morning.rustynewyorker, thanks for the carb tip, I'll be checking for that tagAlso, as for the S and K. I learned they are Engine Plant Code suffix's, and found two sites that both point to the same result. I hope.S = Saginaw serviceK = McKinnon Industries (St. Catherines, Ontario, Canada)The S makes sense since my 3 speed manual trany code is 3858986 (Saginaw 3 speed).
The K checks out against the web sites listed, but conflicts with the F (Flint manufacturing plant) code at the begining. Free download font for windows xp. Hmmmmm?Still looking.
I have searched the casting numbers and am pretty sure I have a 216. I have the engine serial number from my VIN plate but cannot find the engine serial number on the motor.
I have read that dealer replacement engines had no serial numbers and the mechanics were to transfer the numbers to the new engine. The casting behing my distributor is blank snd has no sanding or grinding marks to indicate the numbers were ground off.Re: 1950 Canadian GMC engine serial numbersSun Jan 10 2010 02:37 AM.