I am a C-3 guy and am considering a 66 Coupe without its original engine and want to know what signs to look for to verify it is a original BB coupe. Thanks for any help.

Jerry

 

the oil pres gague. tach, front springs, rear springs, fuel line, location of hood support, size of sway bar, and some more

 

Check the two digit suffix code on the bottom of the rear end.If you don't have a book post the letters.should be one of these.AT,AU,AZ,FA,FB,FC,then the date code. assuming it's the original rear end.good luck

 

One way to check is look at the redline on the tach. If the car was originally a 427ci 390hp (L-36) the redline on the tach would be 5500 rpms. If it was original 427ci 425hp or 427ci 450hp (L-72) the redline would be 6500 rpms.
Another way to check is look at the hood support as someone else already mentioned. If the hood support is on the right side its means that it is an early production L-72 like my car, or it is a small block car (327ci 300hp/ 327ci 350hp) without A/C) If the small block has A/C that the hood support is on the left side. Big Block hood supports are on the left side (again with the exception of very early cars)

 

BB's used the same 9-leaf rear spring as small-blocks; the 7-leaf F-41 HD spring was only available (as an option) with solid-lifter big-blocks.

 

While on the subject of rear ends, you must not neglect to check on the rear half shaft, where they attach to the differential. SB's use U-bolts, BB's use bolt-on caps.

Stepinwolf

 

Could you explain the differnce between U-bolts and bolt on caps, I have a pic of the underneath and can see the half shafts. The hood support is on the left side. He says it was a 390 HP car.

Thx
Jerry

 

all 66big blocks used an 11" clutch with a 14" diameter 168 tooth flywheel, EXCEPT L-88 (which used a 10.4" clutch with a 12-1/2" , 153 tooth flywheel) The '444' bellhousing is designed for use with a 14" flywheel. It was used for 1966 and very early 1967 Corvette with 427 (except L-88). Other BB-SB differences:
front AND rear sway bar
instruments (oil and possibly tach)
Steel line from high limit oil pressure gage to engine.
front springs (tagged)
LH battery holder and BB cables
Riveted battery cable clip near pass. side of tunnel opening
washer fluid bag (on A-C cars)
radiator, shroud, and no aluminum expansion tank
Tapped differential yokes with bolt on caps.
hood
all engine accessories except PS pump
power steering hose and fitting
clutch cross shaft
probably the flywheel and clutch assembly
lower splash shields
2.5 inch exhausts
exhaust heat shields
.375 fuel line with right angle bend to BB pump
different codes stamped on differential
BB throttle lever curves back from pivot toward rear of car, SB is straight
Riveted battery cable clip near pass. side of tunnel opening
Notch cut in front valence of 66-67s above RH bumper bracket
Registration weight shows BB added, "add" weights:
a31 Power window +5
co7 Hard top____+49
c48 less Heater ¬¬¬__-20
c60 a-c¬¬¬_________+93
j50 power Brake ___ +12
L89 aluminum Heads -73
m20 4speed ________-5
m35 powerglide _____+1
n40 power Steering__ +21
u69 radio __________ +21
l79 327/35 0 ________ -8
l36 427/390 _______+215
l68 427/400 _______+151
l71 427/435 _______+149
The base car is a 327 with 3 speed.
Convertible curb weight 3160
Coupe curb weight 3140

 

U-bolts would be similar to exhaust clamps. Threaded rod bent in a radius. The u bolts go around the caps and have nuts and washer to secure the caps.


The bolt on caps would be similar to the main bearing caps on the engine block. Bolts are used to secure the bearing caps.


Jeff

 

Is this a bolt on half shaft?

 

No, it's not.
I can't believe nobody suggested you look for the rear sway bar. Only big blocks had it.

 

He said it had a rear sway bar but it had been removed and not replaced. Are those half shafts for a small block? He did do a partial frame off.

Thx
Jerry

 

Vettes1st "I can't believe nobody suggested you look for the rear sway bar. Only big blocks had it."

Read line 5 of my posted list.

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71vert - the pic you posted shows a little of SB Ubolt at the far right of the pic. The Ubolt attaches to the SB yoke sticking out of the dif. The axles all look the same to me.

 

Thank you I see it now.

Jerry

 

The photo shows small-block diff yokes, a reproduction spring, and end link bolt cushions in desperate need of replacement. If there are not two bolt holes in the top of the trailing arm (one forward and one rearward of the large access hole), it's not a big-block car; those holes were drilled at the plant, only on big-block cars, to attach the brackets for the rear sway bar.

 

Thanks for all the help Even though I cannot confirm for sure It was a big block it does have some traits still, Hood support, throttle lever curves the correct way, there is on old battery holder on the left hand side even though a new one is on the right now, the owner told me he replaced 80 percent of the parts with new parts and since he put in a new 350 he wasnt concerned that the replaced parts were bb parts and he is selling it for a good price so welcome me to my first c-2.

 

71vert, I hate to disagree but the "it does have some traits " just wouldn't cut it with me. His ( previous owner ) above statements remind me of " the check is in the mail thingy ".

So far, from what I can gather, regardless of weather or not the previous owner swapped out some parts, I doubt very much that it is one of the 75,000 big block cars that GM produced every year.

Stepinwolf

 

If the battery holder is on the drivers side, that would indicate an A/C equipped car. All others in 66 were on the pass side. Not sure but A/C might also explain a left side hood support on a small block.

 

I am only paying the price for a nicely restored small block car anyway, if it is a Big Block, then I guess its a plus. I see no reason why he would lie unless he were trying to get BB dollars for it which he is not, but I appreciate all the identification help as always. This is a great forum for learning.

Thanks,
Jerry

 

Congratulations on the car.

The 65 BB cars had the battery on LH - so did A-C cars. When the battery is LH, there is a removeable panel in the LH wheel well next to the battery - for access. If the panel is there, IMO it was an A-C car. If not, either the wheel well panel was replaced, or the battery tray was moved left for some reason. If it's an early 66, the factory may have put the battery on the left, where the BB 65s were.

Hope you drive the car everywhere and enjoy it.