RiversideInspections

Hey everyone, first post here- but I have been reading up on these forums quite a bit during my Father and I's refresh of his 1970 "LT1" Vette.

This car has been a bit of an odd ball from the start, and we would like some help trying to figure something, really anything, about this car. The casting numbers are bold, with a pic of the stamp, and a description of why I'm calling this the- "Strange LT1."

We bought this car about a year ago, the previous owner did not know if the motor was original or correct. The car has an LT1 hood and the guy said it might have been an LT1 so we went to look. The block numbers matched the VIN, but the intake manifold was standard rise cast, the heads were 882's (196/160 I believe) the carb was a newer Holley 650, and the valve covers appear to be aftermarket or off another later vette. Anyway we bought it and have been going through it.


1-Passenger side transmission stamp- 3925661

No pic of this one because it seems to be pretty common.
This appears to be the patent # for a Muncie, would this # be for the correct transmission in an LT1?

1a- Driver side stamp on transmission-3952648



Thinking this may be a part number for this side of the case. Cannot find a VIN on the transmission. (Yet, any ideas?)

2-VIN number-194370S404404


We have already derived the birth date of the car to be 2/20/70, which obviously makes this an early car. The car had A/C at some point in time although the easy A/C stuff has been removed, the A/C components in the firewall remain. The car does not have power steering. I was told that it was possible for a dealer or GM to override options which would allow A/C etc. How possible is this? I'm thinking if it were a dealer over ride or something of the like, they would have optioned for power steering as well. The only reason I could see optioning A/C but no PS is due to the oil pan clearance issue on early LT1. The other option is also that it could have been added at some point in the past by another owner. The car also has a vapor return line which was hooked up when we dropped the tank. I was told that this was not possible on a 1970 LT1...

3-Block casting number (PS left front pad) 70S404404 VO211CTV


Here's where it first started to get a bit dicey for me. CTV code on a regular LT1, not a ZR1? I was under the impression this code was designated for ZR1s exclusively. True? The car does not have dual pin calipers, it has 9 leafs in the rear, no proportioning valve, etc. (no ZR1 parts) The radiator we believe to be copper? 45º neck at it's top driverside. Harrison stamp reading "full when cold" below on the passenger side.



Why are the numbers not in a perfectly straight line? Many that I have seen have been as straight as an arrow, although I have seen pictures of some that look similar to what's shown here. Could it have been stamped by hand due to an issue at the factory that day? Or, was it decked and faked?

4-Manifold number 3832465 gm and also a 5 below these numbers



Sorry for the upside down pic but you get the idea. This number came up correct for an LT1 exhaust manifold. I know the other side is a different number. We don't have a pic of that but it is the correct # for the other side.

6-Rear diff number- 3871375



IIRC, I checked this number to find that it had a 3.42 ratio. I could be mistaken though.

7- Body tag



White ext. / Red int. Haven't found much info on this color combination. Anyone here have it? We'd love to see some pictures, even if not LT1.

8- Bell housing



Thinking this is just a part number as well, couldn't find any info on it.

9- Since I know you guys will want a before / after (thus far anyway)
BEFORE-



10- AFTER



Obviously still not done & a lot left to do but you get the idea. I have replaced the fuel pump, flex lines, hard lines, heads, intake manifold, and cleaned / painted the motor.


Any help would be greatly appreciated. I have tried to give as much info as I can remember right now, but I'm sure there will be more. If there are any other questions regarding parts or numbers, pictures or locations, or suggestions on where else too look please let us know. We're not trying to get top flight with this thing, just trying to see what we actually have.

-Dustin K & Jeff K

EDIT: The car has a 5500 redline tach, not the 6500 redline which was supposed to be in an LT1. I can also get more part numbers off the water pump, fan / clutch, etc. if necessary. The car also came from the PO with the ugly LT1 hub caps. We have not found any build sheet or anything after dropping the tank and removing the dash.

Easy Mike

CTV indicates an LT-1 for ZR1 use. No 1970 LT-1s had factory air. Dealers could not over ride the LT-1 requirements, but could have agreed to install factory air at the owner's expense after the car had been delivered. Have you considered the block may have been restamped? GM did not keep color combination data so there is no way to determine how many white cars had red interiors. Just the same, white with red was a popular combination. My hunch says what you consider LT-1 hubcaps are likely to be a set of optional P02 wheel covers.

This might help answering some of your questions:

gbvette62

1 & 1a) Are casting numbers, and common to most Muncie's. The VIN, along with the date and identification suffix code, can be found stamped vertically on the right side of the trans, where the tailshaft housing bolts to the main case. "A" for M20, "B" for M21 & "C" for M22. The M22 would only have been available with a ZR1.

2) All the VIN tag can tell you is that the car was a coupe (37). Someone may have added AC to the car, at some point in the past, but I'd doubt it. NO LT-1 used the right side vapor return line, if it's there, then it isn't/wasn't an LT-1.

3) That is not the "Casting Number". The casting number is found "cast" into the left rear of the block, on the flange where the bell housing bolts up.

That is the stamp pad, and the VIN derivative stamp and engine suffix stamp. CTV is the suffix code for a ZR1, but it doesn't look typical of a factory stamping. The pictures aren't great, but from what I can see, both stampings look suspect, and I can't see any "broach" marks, in the pad.

The only 70 that used an aluminum radiator, was the base L-48 with a 4 speed, and no air. All others (LT-1's, 350/350, all automatics, and all air conditioned 350's) used a copper radiator, with attached tanks and a filler cap on the radiator.

4) The 3932465 is NOT the correct manifold, for a 70 LT-1. The LT-1 used 3932461 on the right, and 3969869 on the left. The 465 is the right hand manifold for a 70 350/300 & 350/350.

6) That is the rear end casting number, and won't tell you anything about the ratio in it. The ratio can be identified by a 2 letter code, that's stamped on the machined pad, on the underside of the rear.

LT-1's and ZR1's would have used the rear end stub axles, with the cast iron U-joint caps. I can see in your picture, that the U-joints are installed at the rear, using U-straps, which were only used with 300 and 350 horse engines.

7) As you already know, the car was originally white with a red interior. The only other thing the trim tag can tell you is that the body was assembled on February 20, 1970 (B20).

8) The 621 is the bell housing used in all 70 4 speed cars, with an 11" clutch.

9) I don't see anything under the hood, to make me believe that the car was ever an LT-1. The valve cavers are an aftermarket item. Since you've had the heads off, what kind of cam is in it? The LT-1 used a solid lifter cam, while all other small blocks used a hydraulic cam.

The water pump, and fan clutch, are the same for all 70 engines. All LT-1 used a 5 blade fan, 7 blade fans were only used with AC cars.

Welcome to the Forum, but you may want to post in the C3 General or Technical sections, in the future. You'll get many more views and responses there.