can someone tell me how to I.D. a motor i just bought in a parts rig..its a 1980 3/4 ton...motor is supposed to be a 400..i need to know where to look and what to look for..Thanks

Look at the harmonic balancer and see if part of the outer ring is cut away or completely solid

Look at the harmonic balancer and see if part of the outer ring is cut away or completely solid

also 400 has 3 freeze plugs instead of only 2 (well mine does). but yeah that big funky harmonic balancer is usually the first sign. when i saw mine i thought it was broke or something and showed it to someone and they told me i had a 400

pull 1 of the valve covers and write dwn the nus
then
loook at the "deck " - ledge behind the alternater ( were the head meets the block)
then Grad a flash light and a rag and probably some cleaner and a brush then lay on the air cleaner and lean to the drivers side back of the motor By the fire wall and look on the ledge just before the tranny bell housing is the casting nu's
\ then take all these nu"s and go to moretech.com and nastyz.com
Hope it helps
R

Look at the harmonic balancer and see if part of the outer ring is cut away or completely solid
look at the INSIDE of the balancer too. some had material removed from the inside, where you couldnt see it.

also 400 has 3 freeze plugs instead of only 2 (well mine does). but yeah that big funky harmonic balancer is usually the first sign. when i saw mine i thought it was broke or something and showed it to someone and they told me i had a 400

400s are not always provided with 3 freeze plugs. many were cast with 2 on each side.

Mortec and www.73-87.com have good info, look up the suffix codes.

no one has mentioned that 400's have bulges on the sides of the blocks due to slightly larger bore sizes. 350's will be flat from front to back, while 400's will obviously have 4 bulges on each side.

I use sites like NastyZ (http://www.nastyz28.com/sbchevy/sblock.html) to verify what I have:

Find the engine ID code, casting date, VIN code and the Engine block casting number. Use the site above to tell you what you have, etc

Find you casting number- from a quick look at that site, it looks like your should be(if that motor was orig)
Year casting# CID low power high power Comments
1973-80 #330817 400 150 180 car/truck
1970-80 #3951509 400 150 265 car,truck

There are lots of sites you can use- results may vary, but I was able to nail down my last 5 motors using it

wow,thanks guys im going out there and check it out...

thanks for the help guys but ill have to wait til i pull the motor and clean it up cause it was hard to see the numbers...all but the ones under the valve cover and from what i found out its 283-327 heads from 62-64.and for the block if the 8 i wrote down was a 3 it is a 70-73 california camaro 350 at one site or a 69 -76 350 at the other site.lol.im not a big chevy guy but im pretty sure 327 heads wont fit on a 350.right.
so im pretty sure now its not a 400 .and that was the only reason i bought that truck..oh well ,ive always been to trustworthy..it does run good though...
thanks again for those links ,ill use them again when i have the motor out and can see the numbers more clearly...

thanks for the help guys but ill have to wait til i pull the motor and clean it up cause it was hard to see the numbers...all but the ones under the valve cover and from what i found out its 283-327 heads from 62-64.and for the block if the 8 i wrote down was a 3 it is a 70-73 california camaro 350 at one site or a 69 -76 350 at the other site.lol.im not a big chevy guy but im pretty sure 327 heads wont fit on a 350.right.
so im pretty sure now its not a 400 .and that was the only reason i bought that truck..oh well ,ive always been to trustworthy..it does run good though...
thanks again for those links ,ill use them again when i have the motor out and can see the numbers more clearly...

350 HEADS WILL BOLT ON A 327, 327 HEADS BOLT ON A 350, 265/267/283/302/305/307/327/350/383/400 engines are all based on the same architecture, for the most part. SBC engines from 1955-1987 are pretty much interchangeable, and remain mostly that way for the 1st generation design til 1999.

get the two or three letters at the end of the number STAMPED into the end of the block behind the alternator, on the deck surface. take those 2/3 letters to www.73-87.com and look up "SUFFIX CODES" and find them there. that will tell you what it is, what the original hp rating was, and the application.