Do I have a LT1 or LT4?
11-25-2013, 01:31 PM
#1
5th Gear
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Do I have a LT1 or LT4?
I need help. I recently bought a 1956 Chevy 3100 with an LT engine in it. I am not sure if it is an LT1 or an LT4.
It has the red intake manifold of the LT4 (which was not spray painted), but it has the valve covers of the LT1.
Also, my alternator is located on the passenger side, and the alternator on the pictures online vary. I'm thinking they moved the alternator to make the engine fit, or to delete the A/C.
Is there a number on the engine that I can check for sure?
It has the red intake manifold of the LT4 (which was not spray painted), but it has the valve covers of the LT1.
Also, my alternator is located on the passenger side, and the alternator on the pictures online vary. I'm thinking they moved the alternator to make the engine fit, or to delete the A/C.
Is there a number on the engine that I can check for sure?
11-25-2013, 01:47 PM
#3
Race Director
Easy way to find out if it has LT4 heads is to take the oil fill cap off, and shine a flashlight in.
If they are LT4 heads, you'll see "LT4" embossed on the head casting.
You'll also notice the factory roller rockers.
As far as I know, the valve covers are the same on a '96 LT1 and LT4
If they are LT4 heads, you'll see "LT4" embossed on the head casting.
You'll also notice the factory roller rockers.
As far as I know, the valve covers are the same on a '96 LT1 and LT4
11-25-2013, 02:03 PM
#4
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11-25-2013, 02:04 PM
#5
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Easy way to find out if it has LT4 heads is to take the oil fill cap off, and shine a flashlight in.
If they are LT4 heads, you'll see "LT4" embossed on the head casting.
You'll also notice the factory roller rockers.
As far as I know, the valve covers are the same on a '96 LT1 and LT4
If they are LT4 heads, you'll see "LT4" embossed on the head casting.
You'll also notice the factory roller rockers.
As far as I know, the valve covers are the same on a '96 LT1 and LT4
I'm hoping it's an LT4!
11-25-2013, 02:07 PM
#7
PO - previous owner
You actually need to start with the very basics to ID what you've actually got. The accessory placement doesn't dictate anything except the front mount & drive the builder used. You can ID the rockers from already posted information BUT that's not maybe enough to confirm the "engine build". Way more investigation required.
You actually need to start with the very basics to ID what you've actually got. The accessory placement doesn't dictate anything except the front mount & drive the builder used. You can ID the rockers from already posted information BUT that's not maybe enough to confirm the "engine build". Way more investigation required.
11-25-2013, 06:38 PM
#8
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PO - previous owner
You actually need to start with the very basics to ID what you've actually got. The accessory placement doesn't dictate anything except the front mount & drive the builder used. You can ID the rockers from already posted information BUT that's not maybe enough to confirm the "engine build". Way more investigation required.
You actually need to start with the very basics to ID what you've actually got. The accessory placement doesn't dictate anything except the front mount & drive the builder used. You can ID the rockers from already posted information BUT that's not maybe enough to confirm the "engine build". Way more investigation required.
11-25-2013, 07:30 PM
#10
Team Owner
There is a tab on the passenger side of the block just in front of the cylinder head. What's stamped there?
Your pics didn't show up, but I was able to copy the link to the photobucket site and they really won't do much to help. It looks like the throttle body is either an aftermarket or a replacement piece. LT4 TB's will also be red and have the "Grand Sport" tab on top.
Your pics didn't show up, but I was able to copy the link to the photobucket site and they really won't do much to help. It looks like the throttle body is either an aftermarket or a replacement piece. LT4 TB's will also be red and have the "Grand Sport" tab on top.
11-25-2013, 07:44 PM
#11
Le Mans Master
http://www.grandsportregistry.com/GSBuyersGuide.pdf
Should clear it up for ya
The engine block also has a VIN stamping on the flange edge of the block, rear section on the driver’s side near the
bellhousing mating surface. However, it cannot easily be viewed with the engine still in the car as it is very tight to
the firewall back there. As an alternative, to verify that the engine is an LT4 and at least ascertain the date it was
produced, there is a stamping on the passenger front side of the block below and to the right of the ignition coil, near
the power steering reservoir. It is on a horizontal lip of the block and can be seen with a flashlight and without
disassembly of any components. The stamping will be something like “V0000ZXD”. V stands for Flint, MI
production plant, and the 0000 is the date of production not including the year (ex. 1021 would be 10-21-95 and
0520 would be 5-20-96 based on 1996 production model year runs) and ZXD is the suffix code for LT4. The date of
this stamping should be just prior to the build date of the GS; which is available to members on the GSR web site.
Also, if you pull the oil fill cap and shine a light inside you will see “LT4” stamped inside.
bellhousing mating surface. However, it cannot easily be viewed with the engine still in the car as it is very tight to
the firewall back there. As an alternative, to verify that the engine is an LT4 and at least ascertain the date it was
produced, there is a stamping on the passenger front side of the block below and to the right of the ignition coil, near
the power steering reservoir. It is on a horizontal lip of the block and can be seen with a flashlight and without
disassembly of any components. The stamping will be something like “V0000ZXD”. V stands for Flint, MI
production plant, and the 0000 is the date of production not including the year (ex. 1021 would be 10-21-95 and
0520 would be 5-20-96 based on 1996 production model year runs) and ZXD is the suffix code for LT4. The date of
this stamping should be just prior to the build date of the GS; which is available to members on the GSR web site.
Also, if you pull the oil fill cap and shine a light inside you will see “LT4” stamped inside.
11-26-2013, 05:19 PM
#12
Le Mans Master
There is a tab on the passenger side of the block just in front of the cylinder head. What's stamped there?
Your pics didn't show up, but I was able to copy the link to the photobucket site and they really won't do much to help. It looks like the throttle body is either an aftermarket or a replacement piece. LT4 TB's will also be red and have the "Grand Sport" tab on top.
Your pics didn't show up, but I was able to copy the link to the photobucket site and they really won't do much to help. It looks like the throttle body is either an aftermarket or a replacement piece. LT4 TB's will also be red and have the "Grand Sport" tab on top.
11-26-2013, 11:30 PM
#13
Le Mans Master
After all this time, and if the engine has been swapped to another car, you are only left with casting numbers. Even then, who knows what's been done to, or replaced on the engine by now. It does look like a stock LT4 manifold, which would require either an LT4 head, or LT4 aftermarket design, as the intake runners are different from the LT1's.
The throttle body on both engines were the exact same part, and the "grand sport" tab could've been removed years ago. So, that leaves you with casting numbers. As said, if the heads are LT4 originals, you will see "LT4" cast in the head at the oil filler, as well as aluminum RR's, these will have a bowtie logo on them as well.
But all of that can be a moot point, because who knows what the internals are? Like I said, by this time, anything could have been done to it. It could very well be an LT1 with an LT4 conversion kit.
The throttle body on both engines were the exact same part, and the "grand sport" tab could've been removed years ago. So, that leaves you with casting numbers. As said, if the heads are LT4 originals, you will see "LT4" cast in the head at the oil filler, as well as aluminum RR's, these will have a bowtie logo on them as well.
But all of that can be a moot point, because who knows what the internals are? Like I said, by this time, anything could have been done to it. It could very well be an LT1 with an LT4 conversion kit.
11-27-2013, 06:30 PM
#14
Racer
If you decide you want to check internals I would look at the crankshaft. The casting numbers are the same (14088526) for the LT-1 & the LT-4, but the LT-4 has rolled fillets. Just to let you know I got this information from "How to build max-performance Chevy LT-1 / LT-4 engines.