# DECODING CHEVY ENGINE



## 66IMP

MY ENGINE HAS NUMBERS ON THE BACK OF BLOCK ON DRIVER SIDE
3951509
WHAT SIZE MOTOR IS IT,HOW CAN YOU TELL


----------



## triple X level

> _Originally posted by 66IMP_@Feb 4 2007, 08:13 PM~7175568
> *MY ENGINE HAS NUMBERS ON THE BACK OF BLOCK ON DRIVER SIDE
> 3951509
> WHAT SIZE MOTOR IS IT,HOW CAN YOU TELL
> *


 years made Disp HP
3951509 1970-80 400 only 150-265


----------



## 66IMP

> _Originally posted by milkweed_@Feb 5 2007, 03:18 AM~7177587
> *years made      Disp                HP
> 3951509    1970-80    400 only    150-265
> *


SO THE MOTOR IS A 400? AND IS THAT CONSIDERED A SMALL OR BIG BLOCK,ALSO 1970-1980 IS THE YEAR OF MOTOR, HOW CAN YOU TELL WHAT THE MOTOR IS FROM


----------



## 66IMP

DISP HP............WHAT DOES THIS MEAN?


----------



## biggeazy-e

> _Originally posted by 66IMP_@Feb 5 2007, 01:33 PM~7179341
> *DISP  HP............WHAT DOES THIS MEAN?
> *


displacement 
horsepower

there was a 400 small block, and i believe a 400 big block, easy way to tell the difference is big blocks came stock with 6 bolt valve covers, small blocks utilized 4 bolt valve covers


----------



## Guest

the numbers you need to decode the engine are located on the front passenger side of the block above the water pump were the head meets the block


----------



## 66IMP

> _Originally posted by milkweed_@Feb 5 2007, 03:18 AM~7177587
> *years made      Disp                HP
> 3951509    1970-80    400 only    150-265
> *


SO HORSEPOWER IS ONLY 150 TO 265? AND THEY WERE MADE FROM 70 TO 80


----------



## 81gutlass

those were the better 400 blocks from what I hear I have one for my camaro if built right those motors can produce a lot of torque and horsepower but if you want it to make a lot of power make sure its a 2 bolt main because the 4 bolt ones are weaker with little effort those motors will produce 400 to 450 hp on a 2 bolt main and can be used as a street/ strip if your into that sort of thing Mor Tec maybe this will help you this will show all chevy casting numbers also if you plan on rebuilding the motor make sure you have the cylinder walls checked very close because they are known for cracking because they are a lot thinner than a regular block


----------



## biggeazy-e

> _Originally posted by 81gutlass_@Feb 6 2007, 08:12 PM~7192891
> *make sure its a 2 bolt main because the 4 bolt ones are weaker *


:dunno: :uh:


----------



## Cuzzo86

> _Originally posted by biggeazy-e_@Feb 6 2007, 09:33 PM~7193569
> *:dunno: :uh:
> *


He right, 4bolt stronger than 2bolt is for 350 not 400.


----------



## biggeazy-e

> _Originally posted by Cuzzo86_@Feb 8 2007, 02:15 AM~7205973
> *He right, 4bolt stronger than 2bolt is for 350 not 400.
> *


read what i quoted one more time.. he has it backwards


----------



## LaidbackLuis

I posted this a while back

MORTEC

alot of usefull info on de coding numbers


----------



## 81gutlass

> _Originally posted by biggeazy-e_@Feb 8 2007, 08:08 AM~7207048
> *read what i quoted one more time.. he has it backwards
> *


copied right out of chevy high performace 

the 400 two-bolt main blocks are preferred since they offer superior strength in the main webbing area compared to four-bolt main 400 blocks.

does it make since now


----------



## biggeazy-e

> _Originally posted by 81gutlass_@Feb 8 2007, 08:29 PM~7212859
> *copied right out of chevy high performace
> 
> the 400 two-bolt main blocks are preferred since they offer superior strength in the main webbing area compared to four-bolt main 400 blocks.
> 
> does it make since now
> *


actually, no.. not because of what you posted, but because i've thought otherwise for a while now..

(BUT- LT1's are two bolt main if i am not mistaken, so that would make it a little more clear)


----------



## Foompla

> _Originally posted by biggeazy-e_@Feb 8 2007, 10:33 PM~7212895
> *actually, no.. not because of what you posted, but because i've thought otherwise for a while now..
> 
> (BUT- LT1's are two bolt main if i am not mistaken, so that would make it a little more clear)
> *


1mz's are 6 bolts


----------



## biggeazy-e

> _Originally posted by Foompla_@Feb 8 2007, 08:59 PM~7213098
> *1mz's are 6 bolts
> *


the 6 bolt shit looks fucking badass.. i wouldn't even assemble one, just leave it belly up in the middle of my living room....


----------



## Guest

4 bolt main 350`s are weaker then a 2 bolt main they had the same problem as the 400 4 bolt main


----------



## 66IMP

SO THESE MOTORS ARE SLOW OR ARE THEY OK,I USED TO DRIVE A REGAL WITH A 46 231 SO A V8 MAY SEEM MORE POWERFUL TO ME. IS IT BETTER TO BUY A 350 STOCK CRATE ENGINE OR DEAL WITH WHAT I HAVE?


----------



## 6Deuced

> _Originally posted by hosscutlass_@Feb 9 2007, 02:25 AM~7216657
> *4 bolt main 350`s are weaker then a 2 bolt main they had the same problem as the 400 4 bolt main
> *


Where the hell did you hear that BS????

4 bolt 350's are much better/stronger than a 2 bolt 350!!!!!!!!!!!!!!!!!!!


----------



## Guest

> _Originally posted by 81juicedregal_@Feb 10 2007, 02:23 PM~7225952
> *Where the hell did you hear that BS????
> 
> 4 bolt 350's are much better/stronger  than a 2 bolt 350!!!!!!!!!!!!!!!!!!!
> *


on a 4 bolt main they drilled the 2 outer bolts into a weak part of the block thats real close to the piston a high rev could cause the webbing to crack(this is cause the hole is drilled parrealle(spell check) to the 2 inner main bolts 

but they know offer a 4 bolt main block were the 2 outer bolts are drilled out at an angle into a very strong area on the block. these 4 bolt mains are stronger then a 2 bolt main


----------



## 66IMP

WHAT IS THE NORMAL ENGINE TEMPERATURE ON A 400 SMALL BLOCK?
SOME PEOPLE SAY THEY RUN A LITTLE HOT


----------

