A surprise under the hood... need some help plz.

[72TealnWhite]

Hello family,

So i bought this truck about 2 months ago..

Long story short , i cracked an exhaust manifold which got my guys under the hood trying to fix. I decided just to get the work done instead of waiting until winter .. and having the risk of doing more damage ..

So i wanted to match up this motor to the truck so i knew what i was dealing with. The shop guys are telling me that this motor has had some work done..

He told me that the cam was new, so i decided to refurbish the heads while at it.

Well , the pistons are .30 larger .. and he said i have good heads .. anyone know of the GM/Chevy 490 heads ?? and he must have bored the cyl, out .30... so am i dealing with a 380 c.i. block? I got two numbers he said came off the block, i was looking for the block casting # to see whats going on. : He gave me two numbers :

"V10Z9TXB" and "CGF338335" are either what i need to find out the details of the block? and 480 heads.. anyone know of these? Thanks for the help
nate

[white71chevy]

idk about your questions but i just wanted to say u have a very nice truck.

[tooter]

Should be able to find what you need here..
http://www.nastyz28.com/sbchevy/sblock.php

[TrkEnvy]

If it was only bored .30 over you have a 355. If the stroke was increased from 3.48 to 3.75 you have a 383.
Posted via Mobile Device

[SWEET7T]

A 350ci that is '30-over' is a 355ci. the 30 is 30-thousants and 30-thousants times 8 = ~5 cubic inches.

V = Engine Plant, Flint
10 = October
Z9 = 29 = 29th day
TXB indicates a 1975 350ci, 165HP 4-bolt.

The CGF # I can't find anything on, maybe wrong number? It could be a partial vin # for the vehicle it was pulled from. Not sure on the heads either, I would want the whole number not just the last 3...

Just do a yahoo/google search for chevy casting numbers and find a list of the number to find out what you have, that is all that I did.

http://www.nastyz28.com/chevy-engine-code-stampings.php
http://www.nastyz28.com/sbchevy/sblock.php
http://www.73-87.com/chevy_ids/sbcid2.htm

[72peace]

How smart would we all really be without google

[72TealnWhite]

thanks all, man i really want to know where this motor came from .. 1975 ? its a 72' truck so.. on goes the search.. i guess those arn't the right numbers . damn.. The search continues
thanks

[bollybib]

Originally Posted by 72peace

How smart would we all really be without google

huh my internet is down say who ??

[bollybib]

Originally Posted by 72TealnWhite

thanks all, man i really want to know where this motor came from .. 1975 ? its a 72' truck so.. on goes the search.. i guess those arn't the right numbers . damn.. The search continues
thanks

There is a lot of detective work that happens once you acquire an old vehicle. You sure have a bi†chen lookin' rig though.

[72TealnWhite]

thanks for the compliments, i still need to come up with a name for her... Update is ... she is being put back together ... heads fully refurbished.. the guy told me it is positively bored .30 over. so does that mean cylinders and pistons .. im not sure... It has a newer cam everything seems to be good.. and my newer Edelbrock 1406 4bbl . I just can't wait to drive her again..

no luck finding the origin of the motor as of yet.. i believe these are the numbers i need ... search search search
nate

[72TealnWhite]

pics?

[72TealnWhite]

ok here we go.

[70cst]

Hey 72TealnWhite ....that is one lookin truck you have. Very nice

[FRENCHBLUE72]

Congrats on the good looking ride..

[72TealnWhite]

Originally Posted by SWEET7T

A 350ci that is '30-over' is a 355ci. the 30 is 30-thousants and 30-thousants times 8 = ~5 cubic inches.

V = Engine Plant, Flint
10 = October
Z9 = 29 = 29th day
TXB indicates a 1975 350ci, 165HP 4-bolt.

The CGF # I can't find anything on, maybe wrong number? It could be a partial vin # for the vehicle it was pulled from. Not sure on the heads either, I would want the whole number not just the last 3...

Just do a yahoo/google search for chevy casting numbers and find a list of the number to find out what you have, that is all that I did.

http://www.nastyz28.com/chevy-engine-code-stampings.php
http://www.nastyz28.com/sbchevy/sblock.php
http://www.73-87.com/chevy_ids/sbcid2.htm

Hmmm. ? this is wierd .. a 1975 350 with 145 h.p.. ??????

[VA72C10]

Very nice truck!

mid to late 70's blocks were sometimes underrated but also HP started to really suffer with the fuel crisis.....

...anyways, with the cam, pistons, and head work you're probably closer to 250-300HP now....

[72TealnWhite]

thanks, i'm just getting into learning the small block chevy ... Is it really a must to know where the block came from, to configure the right parts.. It seems like the PO or before just pieced this block together with parts from diff cars.. like someone told me the exh. manifolds were from a 71-74 corvette, and he mentioned other examples as well. is this not good? or is the chevy 350 a pretty compatible block with most anything from other vehicles? and how can it only be listed at 145 h.p. ? what car or truck did this block come from? sorry lots of questions..... i just want to know where the block came from.. am i looking too hard into it.? i mean is it really not that important to know the roots of your engine?

thanks
nate

[71swb4x4]

I don't see anything saying saying 145hp, I see 165 hp. Looking at the date of 1975 it was made in the middle of the gas crunch, so you are looking at an engine that likely had a 2bbl carb and was made to have some gas savings. It is possible the factory rated it a little "low" to make it appear lighter on gas too.
Never-the-less a 350 is a 350, so with a small amount of work you are probably up above 300 hp very quickly.
350 parts usually swap right across, and the corvette exhaust manifolds are pretty popular. They look fairly stock but flow very well.
Boring a 350 30 over is very common, they bore the cylinders to remove wear and imperfections from the cylinder walls and then the pistons are also 30 over to compensate for the larger cylinders. Usually they bore it whatever they have to, so if they can get by with 10 over they will.

[72TealnWhite]

does boring it out pose a threat to the block itself? Still trying to find the origins of this motor..

[71swb4x4]

Most of the info was pointed out above. Here is what I got:
V10Z9TXB is probably V1029TXB
V = Flint, MI
10 = October
29 = 29th day of the month
TXB = 1975, 350, Conv. Cab, 165 hp, 4 barrel carb, C20 - 3500 truck

Boring it out 30 thousandths is nothing to worry about.

[72TealnWhite]

thanks, that 165 h.p. in a C20 .. is that legit? it states 4bbl.. what was stock h.p. off the lot back in 72? or 75 ? should have her back in a cpl days..

[bruceman1968]

Nate, TXB is your suffix code. Suffix codes are often used for more than one year.
TXB =75 350 Truck 160hp LS-9 Manual 4-Brl C-20 & C-30 or
TXB =76 350 Truck 165hp LS-9 TH 350 4-Brl C-20 & C-30 or
TXB =77 350 Truck 165hp LS-9 TH 350 4-Brl C-20 & C-30 or
TXB =92 350 Truck 210hp L-05 700 TBI 20, 30, C,K (you can probably rule this one out)
To find out which year, check the Date Code. The Date Code is cast into the block on the rear flange near the casting number. It will be a letter (A-L)followed by 2 or 3 numbers. It is "cast" not stamped. The last number in the date code is the last number of the year the block was cast. You have a good motor, just not the original one to your truck. Also very nice looking truck, I really like the teal.
Factory HP ratings for the 350, LS-9, 4bbl
1970 255HP
1971 255HP
1972 175HP
1973 155HP
1974 160HP
1975 160HP
1976 165HP
1977 165HP
Federal emission standards came out in the early 70's. To meet the new standards several things were done including Reducing the Compression Ratio. This is what killed the muscle cars and the HP in our trucks.

[VWBeamer]

Good deal though you gotta a good motor

[72TealnWhite]

[ Reducing the Compression Ratio. This is what killed the muscle cars and the HP in our trucks.[/QUOTE]

Is there a quick fix for this?

Thanks for all the help

Still searching for the origin of the heads ..

[bruceman1968]

Originally Posted by 72TealnWhite

[ Reducing the Compression Ratio. This is what killed the muscle cars and the HP in our trucks.

Is there a quick fix for this?

Thanks for all the help

Still searching for the origin of the heads ..[/QUOTE]

Quicker than you think, Swap out the pistons, Swap out the heads, and swap out the cam. Which of course has already been done on your motor. So your probably good on the HP being bosted back up to 250 plus. Ask your machinist what he thinks your current HP is.

On your heads, you said 490 and later said 480. I think 480 is right, but that's just part of the casting number. If you can get the whole casting number it would help. 480 heads (from back in the day) are 64cc, 283 heads. Which are good heads. The 64cc combustion chamber volume will boost compression over a 76cc combustion chamber volume. But there's more to it than that. Try to get the complete casting number so we can be sure what you have. It does sound to me like the "smog" part of your motor has been taken care of already.

Also Nate, try to get the date code off your block if you can.

Also on this number "CGF338335" I can't find anything on it, so I think it is for tying the motor to the cab and frame, rather than telling info about the motor.(I could be wrong though)