purchased the block & C heads used & brought it home today. from what i've read '68-later 400 ci big blocks have the last 6 #'s of the vin stamped drivers side of block underneath drivers cylinder head... right? i looked & looked all over the block & did not see anything resembling a vin at all. the block has the distinct "396026 G" stamped on the top but i see no vin #. only other stampings i saw were a "68 F" behind the fly wheel & a "CDF" on the block & heads. could that vin number be somewhere else? should the heads have a vin # too? i can take pics & post tomorrow if needed.

Marty

 

The stamping is there on a very small pad. It will start out 38 or 39 then a plant letter followed by the last 6 digits of the VIN of the car it came from.
Here's where to look:


This is a 1971 350 showing the actual stamping pad:

 

 

AHHH HAA!!! PICS WORTH 1000 WORDS!!! THANK YOU! Vin# 38M371153

 

Well, it's a 1968 motor from a Lansing-built car.

 

Likely late production for 68 too based on the VIN derivative.

 

thanks guys. the seller i purchased it from says the motor was originally pulled from an old motor home. i'm curious to see if there are any internal differences in the heads/motor or if it is the same as a 442. i'll let you know.

Marty

 

A motor home engine would be expected to be low-compression.
Probably the same as the L65 station wagon motor that year - did it have a 2bbl or a 4bbl carb?

- Eric

 

i purchased the motor w/ just block, heads & oil pan. intake wasn't attached. Eric, since i don't have the intake how can i tell if the heads are high or low compression?

Marty

 

Well, posting up some pictures for us would always be nice...

Are the heads off or on?
If they're off, look at the pistons. They will have a mark at the forward edge, a V or U shaped notch (or maybe none at all).
If they're not off, then you can see the notches with a borescope through a spark plug hole, OR you'll never really know.

- Eric

 

The only vehicles to get factory-installed G-block motors were 442s and Vista Cruisers. The 442s with 4bbl motors came with big valve heads and flattop pistons. The VCs and 2bbl 442s (the Turnpike Cruiser for 1968) with small valve heads and dished pistons.

 

So i should be able to tell if it was a 2bbl or 4bbl by measuring the diameter of the intake valves & checking the top of the pistons? From what I've read on OFAQ if it was a 4bbl equipped car valve diameter should be 2.072" & 2.000" if it was a 2bbl?

Marty

 

Are the heads on or off?

Do you have a camera?

- Eric

 

yes & yes. managed to pull the drivers side head off while my kid was sleeping. so obviously i didn't have alot of time. i did manage to take a couple cell phone shots posted below. the 2 that are darker were taken showing my plastic japanese mits measuring od across the valves. i had to turn the flash off to see the display... hence the dark pic. measured 2.073 & 1.626... so hopefully this means what i think it does. the pistons appear to be flat surfaced with no cut outs but they do have a dimple in the middle. when wrenching the heads off... i noticed all the head bolts were loose... oil pan had some missing bolts & was loose as well. shooting from the hip here... but i think someones been in here already

Marty

 

here they are...

 

Flat-top pistons (with no front-edge notch marking) + big valves.
This was a 4bbl 10.5:1 engine, as used in the 442.


Y'might say...

Those heads have been off for a long time, judging by the rust on the sealing surfaces - I expect they'll need to be milled a bit, which is neither here nor there, as it's clear from the picture that this is an engine that requires a total rebuild.

Looks like a great core, though, with a great pair of heads.

Now for the complete disassembly and trip to the machine shop for hot-tank, align-bore, valve job, and a thorough wallet vacuuming - With a small child at home, whatever you do, don't let your wife know how much you're spending!

Good luck with it!

- Eric