Corvette_fetish

There is an orange '69 390hp L36 427 for sale in my area. Looks restored. Not serious show quality, but a REAL nice driver. The current owner said to a friend that he was not sure if the car originally came with a big block. On my '79 I know the engine type is included in the VIN. I did not know the '69 was different, so without documentation how can one tell if a '69 BB car is a real BB car or a SB car made into a BB clone later by lord knows who? :confused:

Nowhere Man

by the oil pressure gague, the tach red line, a rear sawy barand so on :chevy

JB

:iagree: It would help if you could tell us which big block it's supposed to be, since the redline & fuel line setup is different for the tripowers than for the L-36 or L-88. The rear sway bar is a pretty good first clue though--it it's there, probably an original BB.

JB

Wicked_SS

Someone told me once that you can tell by how the u-joint at the diff is held on. A small block uses straps over the bearing to connect it to the rearend and big block cars used the block style to connect. Maybe someone can verify this for me.


[Modified by Wicked_SS, 4:15 PM 4/7/2004]

redvetracr

Rearend side yokes will have caps and bolts instead of u-bolts...
...redvetracr

Corvette_fetish

Well, his flyer says the 390hp 427, so I assumed that meant the L36. Beyond that I don't know what you mean by which BB. It does not have the visual characteristics of an L88 or tripower.

And if it was not clearly implied, the numbers do not match.


[Modified by Corvette_fetish, 3:22 PM 4/7/2004]

sray454

Also heavier springs front and rear ( 7 leaf, not 9 ) ...

LeAnn82Collector

The one thing that usually isn't changed when people change from SB to BB is the tachometer. For a 390 or 400HP its redline is 5600, base 350 is 5300, 350-350 is 6000 rpm, 435 horse is 6500.
Other things are a mentioned already, rear sway bar and HD side yokes with caps.
Check the components like the distributor for a tag, alternator, etc. to see if they are the right numbers.

Corvette_fetish

:thumbs: Cool! Sounds like there are enough clues spread throughout the car that something or another may give it away if not legit.

bamavettes

The best way is to check the suffix code on the engine block pad. It will tell you exactly what engine it is. There will be no need for guessing.

On the 69 it will be a two letter code.

Corvette_fetish

:smiliedrool:

PRNDL

1. 1972 was the first corvette model year that included engine info in the vin, so you will have to rely on the clues given above.

2. If the engine replacement was the L-36 engine, I seriously doubt any of this other stuff was changed. It may be fun to upgrade from a smallblock to a bigblock, but not a huge financial incentive to change all the other stuff.... or put another way, if you are going to build a clone and try to pass it off as an original bigblock, you would be more likely to build an L-89.

3. If the current owner suspects it was not originally a bigblock, then I would bet it isn't !! :)

4. The tach and other cues should give it away pretty quick..... but let us know.

MJ

Markm10431

If I remember correctly, you can get a duplicate build sheet for the car from the museum by the Vin. that build sheet will have the RPO# of the engine on it. if you are VERY lucky the original build sheet might be in the top of the fuel tank

Markm10431

another thought.. I would think the motor mopunts would be different as well as the framework supports for the radiator ect.. it would be one detail oriented SOB to hide the modifications

Nowhere Man

:nonod: only from 1981 to 2003

Corvette_fetish

Well, I saw the car again today for sale at a local weekly cruise-in/car show, so of course the first thing I did was look at the tach. The yellow line appeared to start at 5000 RPM, and the red line looked as if it started at 5400 RPM. Keep in mind my view of the tach was from standing outside the driver's door bent down looking in, so the red line could have started at 5300 RPM, but from my perspective it looked like it started at 5400 RPM. It definitely did not start at 5500 RPM or above. I'm sure of that.

It has the BB hood w/ "427" badges, and his flyer says 390hp 427ci (non numbers matching) so I assume that's suppose to be an L36 motor.

So, was the tach the smoking gun? Real BB car or clone?

standup

......try the emmissions control decal, located on the firewall above the steering column.......most people wouldn't think of replacing this......it' has a two letter code on the right of the decal.......CJ = BB; CF = SB........

........it's an outside shot because the decal could have been replaced or painted over or removed......but it's one possible clue towards your end goal.......

BTW, How does the car look and drive otherwise???????

PRNDL

1969 tach redline starts at
350/300 5300
350/350 6000
427/390 5600
427/435 6500

:_dupe:
(already mentioned by LeAnn82Collector
)


[Modified by MNJack, 12:11 PM 4/18/2004]

Biggus Blockus

Since the car is NOM anyway, in my opinion it is not a huge deal that the car appears to have been a small block car originally.

As long as the BB conversion was done well (upgraded radiator, support, shroud, etc) and the car can be purchased at the right price, it might still be one to go for. Agreed, if it is not orginally a BB car, then there should be a comensurate drop in the price but it doesn't mean it couldn't be a great car.

My 65 BB is a numbers car - some days I wish it wasn't so I could drive it a little harder and no feel scared about breaking it!

There are so damn many forged cars out there now anyway, who knows for sure what they REALLY have? Myself included...

Love those orange 69's!

JRD77VET

I was trying to help a friend figure out if his '69 was originally a BB car.

Here's the thread http://forums.corvetteforum.com/zerothread?id=421361

Most of the answers here were given in this thread too.

:seeya Jeff