identify 96-98 vortec

[Barry Donovan]

Got in at the back of the block where someone told me it would be plain as day:
305 or 350.

No. of course not.

mine says SGI or SG1 where the pictures I found were 305 or 350 would be raised letters.
this is in my 1996 gmc.
Could be an older smallblock with vortec top end..as I found a fuel pump boss cover. the vortec is not supposed to need that.

but I am more concerned with displacement.

anyone know what that is?

I could not find liters in the same area, I cannot get eyesight into it.

I did find SGI = Spherodial Graphite Iron
not the real old small block... will keep digging.

there is a row of letters and numbers above this, can't get my fat head in there to see it.
I think I spotted a double triangle and GM.. A letter O

ok, it is later than 1987...that is all I know.


my block with the letter "I" not looking like it does in this photo. I confuse it for a small L or | or a number 1.
and the gm mark is tiny on my block, looks like a little double triangle is next to it... a crown or something.

oh well. I'll look at other places if I can.

[Barry Donovan]

deciphered my own eyeball
For any O shape to be above the "SGI" would make it a 5.0

the last year of smallblock is metric, I just might get a photo of that unique gm logo with some gagdetry.
subtle differences.

I went backyard machinist a long time ago, the subaru junk pile demanded it

[Mark]

vortec 350 is 96-2000 in trucks and to 2002 in vans..
The block is no different than any other one piece rear main seal roller block.. vortec headed or not..
3/4 ton up are 4 bolt mains, 1/2 tons are 2 bolt.
The blocks used with vortec heads the fuel pump boss is there but not drilled for a fuel pump push rod..
but is the same casting as any '87 up one piece seal roller cam ready block 350

[Mark]

but I am more concerned with displacement.

anyone know what that is?

I could not find liters in the same area, I cannot get eyesight into it.


ok, it is later than 1987...that is all I know.
[ATTACH]n1147593[/ATTACH]

in your photo I see 5.7l clearly marked 5.7liter is a 350

[Barry Donovan]

in your photo I see 5.7l clearly marked 5.7liter is a 350

borrowed from the net. I can't even begin to take a photo of the back of the block while in the truck.

the 96-98 does not exactly match that either.
the gm logo is different. The letter I is different on SGI.
just having "SGI" indicates later than 1987.

metric engine is my only guess..
another mystery is fuel pump boss cover. the vortec is not supposed to need it.
little things to find.

anyway, there is a way to know, a boroscope camera can get in there..
I saw all I needed to see.
5.0
1996-98 vortec.

Runs too powerful to assume 305. I simply had to check it to verify.
it has had along run with people who cared, hard telling what may be redone internally.
Very quiet upper end and powerful.

[Mark]

Gm code for the vortec 350 96-2000 truck and to 2002 in vans 350 is
L31
HERE ARE photo's of my 350 vortec crate
with casting #
This is in 3 spots// side above the coolant drain plug and front beside timing cover that is plastic 880

[Barry Donovan]

I will get to looking, thank you.
The RPO code matches, nothing out of the oridinary..
L30 for the 305.
just needed to verify displacement.
evidence so far is 5.0 for sure.

I'll get at the front spots, see if I can get a peek at more numbers.

[Mark]

EASI\YEST WAY IS TO PULL A VALVE COVER..
and run the vortec head casting number..
the 305 vortec heads are a different casting # than the 350 castings..
305 heads.. 305 block

[Barry Donovan]

EASI\YEST WAY IS TO PULL A VALVE COVER..
and run the vortec head casting number..
the 305 vortec heads are a different casting # than the 350 castings..
305 heads.. 305 block

true.
I go by the thermostat opening time, all 350 give a surge.
that is my procrastination...this one goes gentle, hasn't blown the factory plastic side tanks.

I did spot an O shape above the SGI.. has to be 5.0
also on these, the 5.0 factory Y- exhaust is a strain on just the 5.0.. it would have popped the ring at the header if a 5.7 was on a 5.0 header.
little tiny header..

[Dan Barlow]

This thread looks like fun . So , here I go .
You've found the spot where it tells , justjam your finger tip into it for 30 seconds. You should get an impression that will tell you 5.0 , 5.7 or as you said , possibly just 0 .
Also you never know if they were short of 5.0 blocks one day and just stuck 305 heads on a 350 or someome put a 350 short block under 305 heads, you never know till you check . Maybe you can get an inspection mirror back there if the impression trick doesn't work .

[Barry Donovan]

This thread looks like fun . So , here I go .
You've found the spot where it tells , justjam your finger tip into it for 30 seconds. You should get an impression that will tell you 5.0 , 5.7 or as you said , possibly just 0 .
Also you never know if they were short of 5.0 blocks one day and just stuck 305 heads on a 350 or someome put a 350 short block under 305 heads, you never know till you check . Maybe you can get an inspection mirror back there if the impression trick doesn't work .

I have done that myself. the H.O from a 1984 SS onto a 350.
it shook a mobile home park.

I'd know if the 305 vortec heads was on a metric 350.

I am at gmt400 now, I am simply trying to narrow down casting.. as it is a 305 vortec for sure. post 1987 block.
I strangely found the 3 triangle you would find on the heads, on the block.. and a tiny gm logo next to it. Trying to get some info.
must mean genuine is my only guess.

at 359k miles and perfect, a goodwrench looking black oil pan (ever notice they never lose, even in the north?) It has been done right, pro work. Even the connectors, nothing is moved or broke, unless deemed a problem.

[squirrel]

What are you trying to identify? Sorry, but I always have trouble deciphering your posts, since you seem to talk in a different way than most folks.

If you have an engine block that you are trying to figure out what it is, then take pictures of all the important numbers on it. At the front of the block, there should be two stamped sequences, one is the partial VIN, the other is the engine number. The partial VIN has three characters that tell you the carline, year, and assembly plant, as well as the last 6 digits of the VIN (the sequence number). The engine number tells you the engine plant, month/day it was assembled,and the suffix code. I have lots of suffix code info for older engines, but info on the later ones (meaning from the 1980s and newer) is sparse.

Also there is a casting date code on the back of the block, it will be a letter followed by two to four numbers. Month, day, year. Letter for the month is A=Jan, B=Feb, etc. the year may have one or two digits, if it's only one digit, it's the last digit of the year. So A 12 3 would be Jan 12th, 1973, or 1983, or 1993, or 2003, etc.

hope this helps.

[Barry Donovan]

What are you trying to identify? Sorry, but I always have trouble deciphering your posts, since you seem to talk in a different way than most folks.

If you have an engine block that you are trying to figure out what it is, then take pictures of all the important numbers on it. At the front of the block, there should be two stamped sequences, one is the partial VIN, the other is the engine number. The partial VIN has three characters that tell you the carline, year, and assembly plant, as well as the last 6 digits of the VIN (the sequence number). The engine number tells you the engine plant, month/day it was assembled,and the suffix code. I have lots of suffix code info for older engines, but info on the later ones (meaning from the 1980s and newer) is sparse.

Also there is a casting date code on the back of the block, it will be a letter followed by two to four numbers. Month, day, year. Letter for the month is A=Jan, B=Feb, etc. the year may have one or two digits, if it's only one digit, it's the last digit of the year. So A 12 3 would be Jan 12th, 1973, or 1983, or 1993, or 2003, etc.

hope this helps.

I am sorry your eyes on text are different than the other 60 million people on the east coast.
maybe you can be an english teacher and judge children of your locale.. I hang out here to avoid this nonsense Mr. English.

I think I got it figured out.. metric 305, the three extra triangles coincide with the vortec head.
1996-03


it is the same engine with two different texts on the same continent doing the same thing.
Wow.
it is like forums and all the small blocks of the world getting together.
Like a bunch of natives, wearing a different feather.

I am going to stare out my window now, 60 inches of snow in two storms is quite something...

[squirrel]

I'm not trying to be critical, I'm trying to help. But if you write words that make no sense to me, I can't help. You seem to be the only person who writes in a way that makes no sense. I've helped hundreds of guys on several forums over the decades....hardly ever can I not understand what they are trying to say. It's not me.

Good luck.