Wicked_SS

I am pretty new to the Corvette game and looking for a little advice. My console plate says 427/390hp. Is there any way to tell what motor originally came with this rig? There is a 69 396 in it now. What exactly does the trim tag tell you other than body/interior color? This car already has the gas tank replaces so there is no hope in finding the build sheet above it, is there anywhere else you guys have found yours? I've heard of them being stuffed inside the frame also. Thanks

Bearcat

How do you know you have a 396? GM didn't make 396's in 1969. And you can't tell from examination, short of running the numbers on the block or measuring the bore diameter with a pair of calipers.

Also, in 1969, you couldn't tell from the VIN # what engine you had. They didn't start coding that into the VIN until later years. Best way to go is to get the numbers off the block, located on a flat area on the front of the engine just ahead of the passenger side head. Then ask a good machine shop what that engine's from.

topless68

I presume we are talking about a '69? The suffix code on SB and BB is located on the stamp pad directly in front of the passenger side cylinder head. The block number is cast into the block, driver side where tranny meets block. Send me the suffix stamp code and I will look in my Chevy 'green book' and tell you what you have.

There are many ways to tell if the car was/is a BB car. 5/16 fuel line, no return line. Large diameter front sway bar, rear sway bar (SB cars did not have rear sway). The hood will be a BB hood, assuming it is the original. Only BB cars had radiator overflow tanks, assuming this piece is still with the car.....there are many more, these are only a few.

As far as the tank sticker, they are often found inside the wishbone or sombrero, the bracket bolting to the top of the rearend housing, and they are also found inside of the dash.

List the trim tag codes here, they are easily translated for original body color, interior color. :cheers:

sb69coupe

I beg to differ on a couple of these items. An L-36 427 will have a fuel return line, since it was equipped with a quadrajet. Also, the base motor smallblock 4-speed cars w/o AC had a small aluminum radiator with expansion tank.

Tell us what the redline of the tach reads. Unless someone swapped out the tach, that's a good indication of what motor was originally in the car.

jbroughton

You can get some hint as to what engine originally came in your car by checking the yellow zone on your tach. According to the '69 owners manual, the yellow zone on a 427/390 is from 5300-5600 rpm. This was also the same as the 427/400. The 427/435, 427 L88, and 350 LT1 all had the yellow zone from 6300-6500. The base 350/300 has the yellow zone from 5000-5300. And the 350/350 has the yellow zone from 5700-6000.

Of course, all of this assumes that the car still has the original tach! :rolleyes:

Hey, whatever it is/was - the important thing is to just drive it and have fun!!!!

Jeff

topless68

you're right, I'm still thinking L71 and L88 :banghead:

LAvetteman

Exactly, for instance on a 71 the return line was left off on any car with mechanical secondarys carb. So some BB and SB had return lines. Another way to tell besides sway bars is where the redline is on the tach.

Some build sheets have been found under carpet.

The only other info on the trim tag is the build date.

standup

There's an Emissions Control Decal that has a 2 letter code that identifies the engine that came with the car.......not sure where this sticker is located on a '69......

...but on my '71 it's white with black lettering and is located on the firewall directly above the steering column, near the hood latch....

To give you an idea what to look for on the decal: The 2 letter code for '71 350/270HP base is AR.......and AX is an LT1......

If the decal isn't there (maybe the firewall has been repainted), you've reached a dead end.......if it's there it is probably original as I don't think anyone would bother replacing it.......

The block code and engine suffix will only identify your existing motor, but that's handy to know and it's worth chasing......

By all means post your numbers here.......we're all happy to help....

Wicked_SS

What do you mean the was no 396 in 69? It came in every SS Chevelle in 69. Are you referring to a 402 wich came out in 70? Anyway thanks for all the help you guys.

Bearcat

Yes. They called that a 396 even though it was actually a 402, if I remember right.

hunt4cleanair

Standup makes a good point and in 69 the emission 2 letter code for a 390 hp was either CJ or CK. Also big block cars were equipped with a rear sway bar...small blocks were not factory equipped with rear sway bars. If the front is still stock and you can measure the diameter...it suggests the suspension setup, big block or small block as well as the F41 heavy duty suspension. Depending on wear and mileage...shock stickers can also give you some indication...unless, of course it has all been replaced.

I check out an LT1 car a couple of months ago that was cosmetically correct but lacked any of the mechanical and suspension configurations that would have supported an LT1 car. It was never an LT1 car but made cosmetically to look like one and passed off to this poor soul who had run it into the ground and the time came to dump it.

Clink69

the 350/350 No AC 4spd. also had an expansion tank...