66sixtaillights

A friend recently bought a '66 convertible roller project. it was advertised as a big block car. (no engine or transmission). He looked at what he knew to look at, mostly the red line on the tach. When he got it home, he looked at the rear end for numbers and found an AL code reared. it has an early '66 date code on it. This code he believes to be a small block 4 speed rear end. Now he thinks the car was actually a small block. I went to look at it and found a rear sway bar that looks to be original, the patina matches the frame perfectly. I looked at the radiator support and the center mount looks to have never had anything mounted there. The give away to me, beside the tach, swaybar and radiator support markings is the hood support is on the left side with no evidence of a support ever being on the right side and it is a no air car. the battery is on the right side. The hood also appears to be a factory '66 427 hood. Anyone have an opinion one way or the other?

thoyer

Fuel lines on big block cars have a right angle bend where they transition to the rubber line to the fuel pump. SB cars the fuel line was approx a 45 degree angle.

The fuel line is hard (impossible) to change without taking the body off....but..... sometimes it gets spliced as it was on a supposed BB car I looked at that had the right angle but it was spliced under the battery tray.

Also BB cars had a bigger diameter front sway bar.

66 frame I'm doing for a friend - BB Fuel line bend

TAlvarez

Another thing to check on the rear end is the half shaft U-joint caps at the differential. If it's a big block rear it should have the forged U-joint caps. Small block rear ends used U-bolts.

Ted

Vet65te

Dan - You've gotten good advice on what to check for a factory Bigblock 66. These cars were typically driven hard and stuff breaks frequently, whether smallblock or Bigblock so
it's not uncommon to find that parts have been swapped over the years. You mention the tach but didn't say what the redline was but I'm guessing it's the high 6500 redline tach?
On the backside of the instrument cluster are two things to look for, one is easy...the white label with the Red Letters. If you have a high redline tach, more than likely the red letter
code you'll find on the lower backside will be 'LB'. You can actually hold your camera up under the dash to get a pic of it, sometimes you have to use a mirror. The pic below is the
LB from my 66 L72. I should say my L72 that's missing it's original 427 and original close ratio Muncie but it's good enough for me.
The second thing to look for is the date stamp. This is typically higher up on the backside of the cluster and short of taking the cluster out, it can be harder to see or get a pic of.
The date stamp along with the cars VIN/Build Date could be another way to determine if it started like as a factory BB. But...you knew that was coming, right...any and all the items
we've mentioned so far can be added along the way so they are not a guarantee that the car was originally a factory Bigblock.
One other thing to look for and again, if you are thinking this 66 started life as a factory L72, it should have the telltale signs of having Transistorized Ignition. I have two Bigblocks,
the Nassau Blue 66 NOM L72 and a Milano Maroon 65 NOM L78 and neither one still retains the original TI Ignition. Seeing a Ballast Resistor on the firewall will tell you if you still have TI.
On a 66, what to look for is on the drivers side/front of the wheel well. That's where the factory mounted the '3' triangular holes for the factory TI Ignition Module. Pic attached of a friends 66 L72 that still
has it's original TI setup on it.
Do post up some pics, we always love seeing pics.
Mike T - Prescott AZ

66sixtaillights

thanks for the tips, an L36 would not have TI, right?

Vet65te

Actually, it could. The difference is that an L72 had TI as a required option while on other engine options like an L36 427-390 and an L79 327-350 horse the TI could be ordered as an option but not required to have it.
Mike T - Prescott AZ

66sixtaillights

I'm going back over later today, I'll check for holes or the unit. also going to measure front sway bar if it's still there. this car also has no steering stabilizer.

DansYellow66

The 427 accelerator lever on the firewall differs from a SB. A SB leans forward and a BB leans back slightly. It’s a difficult part to change with the engine in the car.

The BB cars ran a slightly larger sway bar (15/16”) than SB cars (7/8”).

To add to Vet65te’s comments, (“Seeing a Ballast Resistor on the firewall will tell you if you still have TI.”), if there is a ballast resister on the firewall the car was either not an L72 with mandatory TI, or the car lost its TI at some point and ran a points distributor. Because so many L72s and L36s (optional TI on L36) lost their TIs over the decades, the presence of a ballast resister is not a very reliable indicator either way.