How to tell if car was originally a BB?

[Monkeywrench]

I'm looking at a 71 today. The guy tells me it was originally a BB but it currently has a 350 in it. He says that it has the original BB transmission and radiator. I have no reason to think he is not telling the truth but how would I go about finding out if this is indeed the case other than finding the tank sticker with RPO codes?

I belive the '71 VIN did not list the engine type...

A quick reply would be apprecited as I am looking at the car this PM.

 

[Monkeywrench]

I've heard that the SB and BB tachometers had different redlines. Can anyone tell me what they are?

 

[JT ZR-Won]

Sorry man, but this is kinda going in unchartered waters for me ........but wouldn't the VIN# give all that info?

Jay

 

[Bullitt]

I think that the redlines were different on special high performance cars only. I'm not aware of a difference between the small block and big block tachs. Check for an original rear sway bar. The transmission really isn't a good thing to hang your hat on, because autos and 4-speeds can be bolted onto anything. Compare the radiator shroud, as they are specific for big blocks. My head is a blank, so I'll hit the books and try to find out more for you.--Bullitt

 

[Camtwister]

Check for a rear sway bar. I think it was 9/16 from the factory and only BB cars came with them. Also if the car has A/C the coolant expansion tank is quite different. Hope this helps.

 

[Bullitt]

That's right, if it's A/C the expansion tank is longer, about 14 inches. Non-A/C has one that's is more round. Give us more information about the car. Was it an LS-5 or an LS-6?--Bullitt

 

[Camtwister]

Just checked the NCRS judging manual for the Tach redlines.
It says:
350-270hp Redline starts at 5300
350-330hp " " " " at 6500
454-365hp " " " " at 5600
454-425hp " " " " at 6500
I believe they are refering to the actual redline not the preceeding portion of yellow.

 

[Monkeywrench]

I'm not sure if It was an LS5 or LS6. My gut tells me it would have been as LS5 as they were far more common (I think less than 200 had the LS6). It has power windows, brakes, steering, AC, 4 Speed. That's about all I know about the options.

It has the BB hood (but anyone can have that). It wouldn't kill me if it turned out to be the 350 but I'd like to know for sure.

The sway bar sounds like a good indication.

As for the radiator, what should I look for to tell the diff between SB and BB?

Sean

 

[Monkeywrench]

Just checked the NCRS judging manual for the Tach redlines.
It says:
350-270hp Redline starts at 5300
350-330hp " " " " at 6500
454-365hp " " " " at 5600
454-425hp " " " " at 6500
I believe they are refering to the actual redline not the preceeding portion of yellow.

Ok so it sounds like between the redline and the sway bar and the A/C expansion tank I should be able to tell.

Thanks guys....

Hopefully i'll be reporting that I now own this car tomorrow

 

[Bullitt]

The small block and big block radiators both had the center mount brackets. The big block differed in that it had two additional C brackets on the right and left, similar to the ones underneath. Two bolts came in from the front of the car with lockwashers. There were insulators placed between the brackets and the radiator. The nipple on small radiators was on the top right, whereas it came out through the side on BB radiators. I'll keep going through my AIM manual.--Bullitt

 

[Monkeywrench]

Thanks to everone for their advice. It turns out that the tachometer, sway bar, coolant tank and radiator all checked out to be a BB car. In addition there was a very old sticker inside the engine bay (covered in 30 years of grease) that listed the motor as a 454. I am assuming it was the LS5. (If it was by some luck a LS6 I think I got myslef a great deal...)
Anyway, I bought it. You can see pics under a new topic:

INTRODUCING MY NEW BABY!!!

Thanks again for your help. I can forsee needing it a lot more in the near future!!

 

[Monkeywrench]

As mentioned the vin code would confirm it as well, nice car again Even i am still smiling

Keith

In '71 and before the VIN did not list the engine option. That started in '72..

Thanks for the compliment...