307 or 327?

[stoutguinness]

Ok, so I have done work on 350's and 454 fords but I have never done a complete rebuild or anything like that. So by no means am I an engine guru. I just picked up a 68 Chevy C10 long bed and the engine is definitely smaller than a 350. I cannot figure out if this thing is a 307 or a 327. I've talked to a few guys around town who know a lot about Chevy's but one will say 307 and the other will say 327. I spent a lot of time yesterday trying to find the casting number or any number that will identify this thing and can't find anything. Is there a way to figure this out without ripping the engine out? I've read a lot of post saying where to look but have not had any luck.
It's obvious that the guy who had it before me has done some different stuff to it, so I don't really know what I'm working with. My goal is to have this be a daily driver so I don't have the luxury of having a machinist tear it apart to tell me all about it haha.

Here's a pic if it helps.

[67c10rustbuket]

Either the casting number behind the driver side head or the stamping with suffix code on the front block deck below the passenger head will tell you what exactly you have. You can check the numbers at nastyz28.com, they have a full engine decoding menu for casting and suffix codes for all GM V8s and also they tell you where to look for these (with pics) just incase my description is confusing. Or reply here with the numbers and one of us can tell you what it is. Good luck!

[SS Tim]

The best thing to do would be to look up the block pad numbers. They should be as shown in the pictures unless they have been milled off during a decking operation. Might have to wire brush or even sand down through to the metal to see them. Tell us what you see as a picture can be really difficult.

[stoutguinness]

The second picture is exactly where I thought I was suppose to look, but there's nothing there. Do people sometimes take the numbers off? Why would they want to do that?

[SS Tim]

Did you clean it down to the metal? The stampings will disappear under a heavy coat of paint alone, much less any gunk. There were numbers there in almost every case. The block may have been decked at some point as I said earlier. This is done to square up a block relative to the crankshaft centerline or after a sleeve sometimes. A long neglected head gasket might also justify a light pass to true up the head surface.

[stoutguinness]

Okay, thanks for the information. Now that I know for sure where it's suppose to be, I'll hit it with a metal brush to see if anything is there. There doesn't seem to be much gunk but it does appear to be painted. I'll let you guys know what I find.

[MudBug]

If the block has been decked then the numbers may have been cut off but scrap the paint off first

[Fldawg]

The best way is the casting numbers on the block, on the drivers side right below the head in the rear, my have to clean up back there and use a mirror , but the numbers are there

[stoutguinness]

So the front stamp says V0429WA... That means that it's a 307 right?

[lpaine]

I'm gonna guess 327, reason being I beleive the oil filler tube at the front of the engine was unique to the 327, could be wrong, but I don't remember ever seeing the filler tube on the front of a 307. Later, Lew

[Stevo427]

V0429WA
Made in the Flint Plant on April 29th
From what I see WA means it could be a
1965-283
1968-307
1969-350
My guess would be the 307

[Stevo427]

Id get the number off the back behind the head on the drivers side. Thats how I checked and found out my 307 turned out to be a 327. Was pleasantly surprised

[67c10rustbuket]

Originally Posted by Stevo427

Id get the number off the back behind the head on the drivers side. Thats how I checked and found out my 307 turned out to be a 327. Was pleasantly surprised

Yep No confusion on the rear numbers and they are cast large so easy to read. like this. 3970010 = 350

[sanford66]

I agree we need the casting #. Joseph

[SS Tim]

Agree, we need to see the casting number to nail down this application. Maybe even the casting date. Let us know what you find. No matter the effort it pays to know what you actually have under the hood.
Here is a site I like that has a lot of good information. It has really grown over the years.
http://www.nastyz28.com/chevy-engine-code-stampings.php
http://www.nastyz28.com/sbchevy/sblock.php

[special-K]

I wonder why you think you can tell it's smaller than a 350? They all look the same. Does it have the small harmonic balancer?

[jjzepplin]

Yep mine says 3970020 and it's a 307... go to NastyZ28.com and bookmark it! Back of engine is hard to get to with the engine installed but will tell you all you need to know. Also can tell a lot from the size of the balancer on the front of the crankshaft.

[stoutguinness]

I'll have to keep trying to see the back numbers. Maybe I'll try using a mirror or something. I can see where those numbers are, just not well enough to see the numbers. I'll get back to you guys and let you know what I find.

[special-K]

That's what you need,a flashlight and mirror.

[VWBeamer]

Same here, and the oil filler intake can be put on any pre 87 SBC engine IIRC, so that's really means nothing.

It could be any thing from a 265 to a 383 or bigger even.

Originally Posted by special-K

I wonder why you think you can tell it's smaller than a 350? They all look the same. Does it have the small harmonic balancer?

[406 Q-ship]

Did anyone notice, that engine has later heads.......centerbolt valve covers. That engine could be anything cause I can tell it is put together from parts. Even if you get the casting number it will only tell you the size of the bore when the block was cast. 3970010 means a 4" bore and large journal, it probably will be a 350 but still can be a 327 (put a 307 crank in a 350 block....instant 327).

Originally Posted by VWBeamer

Same here, and the oil filler intake can be put on any pre 87 SBC engine IIRC, so that's really means nothing.

It could be any thing from a 265 to a 383 or bigger even.

The heads have to be from 1987 and later due the centerbolts....but an earlier oil filler intake can be used on them if you slot the center four holes in the intake manifold.

[SS Tim]

Yes, I figured it is some sort of a frankenmotor. But the best place to start is with the block. Then ID the other externals as required. We can ID the block, heads, intake and carb by the numbers and arrive at an as built spec for each. After 40 years anything is possible and actually even likely. I'd say probably less than 10% of the board trucks have an original (as delivered) carb..

[stoutguinness]

I have no problem (really) with a frankenmotor. The only thing that makes things hard is not knowing what everything is. Makes it a little harder to work on haha. So let me ask you guys this, if you had this truck with this engine (and limited budget), would you just run it for now and save your pennies for a new engine and hope to find a good deal, or work on it one piece at a time?

[SS Tim]

If it runs with a reasonable level of reliability, then there is no immediate need to change it. Lets try and ID what you have and go from there. You get to do the dirty work, but learn as well. Somewhere along the line we will likely ask for the intake and head casting numbers. So if you see them write'm down.

[stoutguinness]

okay, so quick question. My wife is due any day now so I don't have the time/money to tear everything apart yet. I would like to drive it the next couple weeks until I'm able to change out the 2bbl carb and steal intake manifold to a 4bbl carb and aluminum manifold. Main problem being is, I have no clue when the fluids were last changed. It's my understanding that it's been sitting for a minute so I want to change all the fluids. Radiator, oil, tranny, brake. Any recommendations on fluids to use or how I go about making sure I use the right amount of oil? I can assume that the dipstick is correct but I'd rather not assume anything with this truck. Any other recommendations?