Original equipment

[Florida3door]

How do I find out what engine my 1968 gmc suburban came with? I know from the vin number that it was a v8 but it doesn't specify 327 or 396. I do have a th400 transmission if that has anything to do with it.

[Bigdav160]

I think you'd get better views and an answer if the mods would move this thread from the build/project section to the general section

I can't answer your question definitively. Is it a 3/4 ton? I would think a 3/4 tone 2WD would have a TH400 with either a small or big block. Someone should know for sure.

There has to be some differences between small and big block trucks like fuel lines, mounts, hangers etc...

[briank]

What does your spid say? I have a 68 gmc burb and mine is a 327

[special-K]

307 was the standard V8 in '68, so that's what it had. only options are listed

[vectorit]

There were a few engine options, and the SPID would tell what CID was ordered.

[Florida3door]

Where is the spid? I have the vin # , but the tag and the glove box is nissing

[special-K]

That tag in the glovebox is your SPID, VIN won't tell you. the only thing else would be a build sheet, if it's still in the truck...usually in the seat springs. or, what about those GM restoration packs? Or, isn't there a site you can trace a VIN and get your exact build and how many others just like it? There is for later years, just not sure how far back it goes. If it was a big block the engine towers were different and there would be evidence of factory dual exhaust

[Florida3door]

Thanks ill dig around for the build sheet.

[burb71]

1968 had 3 V8 engines to choose from, a standard 307, an optional 327 or 396.

If the truck is 2wd and has a high tranny hump in the floor it was a big block truck.
So if you dont have high floor that narrows it down to the stndard 307 or optional 327.

If you still have some of the original factory chalk markings on the upper fire wall under the hood check to see if you have the marking... ( L30 ) this is the option code for the 327.

If you have markings, but no L30 it must have had the standard 307

[Hart_Rod]

Do you have a picture of the engine compartment? There are a couple of things that might also indicate a big block. There's a heat shield of the passenger side engine compartment. Also, most big blocks had a high hump transmission cover, as mentioned above. OBTW, I found my build sheet for my burb under the front carpet....

[burb71]

Originally Posted by Hart_Rod

Do you have a picture of the engine compartment? There are a couple of things that might also indicate a big block. There's a heat shield of the passenger side engine compartment. Also, most big blocks had a high hump transmission cover, as mentioned above. OBTW, I found my build sheet for my burb under the front carpet....

68s did not have the exhaust heat sheild, at least my two original 1968 Big Blocks don't