Help me decode my engine - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dieselarmy13 · 10-31-2008, 02:17 PM

Ok, I know there is a bunch of sites to help you decode your engine, and I've been to 'em all. Maybe I'm just dumb, but I can't figure it out for sure. It has a short water pump and 'goofy' (according to the guy at the exhaust shop) manifolds. Not sure of the originallity of these, as the PO seemed to use whatever was laying around his farm to kkep it going. Also, what kind of heads are these, and are they any good? Any help would be appreciated.

Rreemo · 10-31-2008, 02:45 PM

I can help you, but I will need the casting number off of the rear drivers side of the block. Top of the deck where the block bolts to the bellhousing....should be behind the head, get back there with a light....a little difficult to see with the engine in the truck, you'll have to lean over in there to see it.

For the heads it is best if you just pull a valve cover...the casting numbers and date codes are under there.

dieselarmy13 · 10-31-2008, 02:52 PM

Thanks. As soon as I get her back from the exhaust shop tonight, I'll try to get a pic of the other number.

70rs/ss · 10-31-2008, 02:59 PM

TWF 77 350 Truck 165 LS-9 TH 350 4-Brl
TWF 79 305 Truck 175 L-03 TBI

That wasn't too hard? Want the link?? I figured you would, here ya go!:

http://www.chevymania.com/partsid/

The suffix code is usually only 3 letters, so I just used the last 3, but if I use the middle three I got:

CTW 76 400 Impala 175 LT-4 T-H 400 4-Brl
CTW 78 305 Buick 145 LG-3 TH 350 2-Brl Century, Regal

But I am about 99% sure it is the last 3 so it is either a 350 or 305, and the casting date will be the 100% for sure way to determine which one it is.

Rreemo · 10-31-2008, 03:24 PM

Quote:

Originally Posted by 70rs/ss

But I am about 99% sure it is the last 3 so it is either a 350 or 305, and the casting date will be the 100% for sure way to determine which one it is.

Or the stamp on the rear of the block.

dieselarmy13 · 10-31-2008, 03:25 PM

Thanks 70. Those are the four I had it narrowed down to, just wasn't sure if I was missing something.

70rs/ss · 10-31-2008, 03:55 PM

The casting number at the back of the block is not 100% as GM reused a lot of the casting #'s too such as the famed 0010 block as it can be a 4-bolt 350 or a 327 or a 400, but only during certain years, which is why the casting date, pinpoints when the block was cast and therefore if the suffix or casting number offers 3-4 options, but only one during that year, the casting date then makes it a 100% for sure deal.

10-31-2008, 02:17 PM	#1
dieselarmy13 Phone's ringin Dude. Join Date: Mar 2007 Location: Colorado Springs Posts: 1,426	Help me decode my engine Ok, I know there is a bunch of sites to help you decode your engine, and I've been to 'em all. Maybe I'm just dumb, but I can't figure it out for sure. It has a short water pump and 'goofy' (according to the guy at the exhaust shop) manifolds. Not sure of the originallity of these, as the PO seemed to use whatever was laying around his farm to kkep it going. Also, what kind of heads are these, and are they any good? Any help would be appreciated. __________________ I pitty the fool with only two headlights!! 2003 SILVERADO SS--THE NEW GIRL 1972 GMC--THE OLD GIRL

10-31-2008, 02:45 PM	#2
Rreemo Registered User Join Date: Oct 2005 Location: North Texas Posts: 179	Re: Help me decode my engine I can help you, but I will need the casting number off of the rear drivers side of the block. Top of the deck where the block bolts to the bellhousing....should be behind the head, get back there with a light....a little difficult to see with the engine in the truck, you'll have to lean over in there to see it. For the heads it is best if you just pull a valve cover...the casting numbers and date codes are under there. __________________ 72' LWB Cheyenne 73' Camaro Z28/RS 70' Chevelle RagTop 00=ss=00

10-31-2008, 02:52 PM	#3
dieselarmy13 Phone's ringin Dude. Join Date: Mar 2007 Location: Colorado Springs Posts: 1,426	Re: Help me decode my engine Thanks. As soon as I get her back from the exhaust shop tonight, I'll try to get a pic of the other number. __________________ I pitty the fool with only two headlights!! 2003 SILVERADO SS--THE NEW GIRL 1972 GMC--THE OLD GIRL

10-31-2008, 02:59 PM	#4
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,270	Re: Help me decode my engine TWF 77 350 Truck 165 LS-9 TH 350 4-Brl TWF 79 305 Truck 175 L-03 TBI That wasn't too hard? Want the link?? I figured you would, here ya go!: http://www.chevymania.com/partsid/ The suffix code is usually only 3 letters, so I just used the last 3, but if I use the middle three I got: CTW 76 400 Impala 175 LT-4 T-H 400 4-Brl CTW 78 305 Buick 145 LG-3 TH 350 2-Brl Century, Regal But I am about 99% sure it is the last 3 so it is either a 350 or 305, and the casting date will be the 100% for sure way to determine which one it is. Last edited by 70rs/ss; 10-31-2008 at 03:03 PM.

10-31-2008, 03:25 PM	#6
dieselarmy13 Phone's ringin Dude. Join Date: Mar 2007 Location: Colorado Springs Posts: 1,426	Re: Help me decode my engine Thanks 70. Those are the four I had it narrowed down to, just wasn't sure if I was missing something. __________________ I pitty the fool with only two headlights!! 2003 SILVERADO SS--THE NEW GIRL 1972 GMC--THE OLD GIRL

10-31-2008, 03:55 PM	#7
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,270	Re: Help me decode my engine The casting number at the back of the block is not 100% as GM reused a lot of the casting #'s too such as the famed 0010 block as it can be a 4-bolt 350 or a 327 or a 400, but only during certain years, which is why the casting date, pinpoints when the block was cast and therefore if the suffix or casting number offers 3-4 options, but only one during that year, the casting date then makes it a 100% for sure deal.

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