Big Block or other?

[MarkM]

I'm new to matching numbers and such, having just attended a class at Bloomington. Would someone tell me how I can tell if a 63 - 67 was a big block car if the engine is nom? I've heard something about rear sway bars and tachs with higher red lines. Also about radiator mounts, but don't know enough about any of these to tell a big block car from any other.

Have the Black Book, but don't think that helps without the engine, right?

Thanks,

Mark

 

[74bigblock]

Best way to tell if it's a BB car is to get underneath and feel the top side of the front X-member. Right in the middle on the back side on top, there will be an indentation in the x member. Only BB cars have that indent. Everything else can be easily faked... hard to fake that X-member though!

 

[Tom Bryant]

Welcome aboard Mark. Good advise from Dave in the above post but don't waste your time feeling up a '63-'64 as the '65 396 was the first BB. There are a lot of fakes out there that even the best can't easily tell.

Tom

 

[MarkM]

Thanks Dave and Tom, I would have never known about the indent. Any idea why the indent is there?
Mark

 

[BarryK]

there are a numer of telltale clues between BB and SB cars. A lot of times you can tell if an original SB car was converted to a BB car, BUT as BB cars are becoming more and more valuable people are becoming more adept at cloning a car into a BB car and making changes to all these little details to pass it off as an original BB car to get big money out of it. The only way to know FOR SURE is documentation (and that can be faked up too). Unfortunately, it a "buyer beware" market!

 

[74bigblock]

Thanks Dave and Tom, I would have never known about the indent. Any idea why the indent is there?
Mark

To clear the big @ss oil pan!

 

[BarryK]

Best way to tell if it's a BB car is to get underneath and feel the top side of the front X-member. Right in the middle on the back side on top, there will be an indentation in the x member. Only BB cars have that indent. Everything else can be easily faked... hard to fake that X-member though!

I may be wrong (and I'm sure someone who knows more will chime in if i am) but I thought all frames from '65 on had the indentation in that front cross member. It was added on in '65 to allow for the 396 BB motor but they used the same frame for all the cars, BB or SB. I don't remember if it was started at the beginning of '65 or later on though the year when the 396 was introduced.

 

[mcditalia]

The indent was made to clear the extra girth of the BB. Correct me if I'm wrong anyone, but didn't SB cars also have this indent after 65? I thought the indent was made on all the x members after 65 to ensure that if it did go on a BB car it would have the extra clearance. Sorry if I'm creating any confusion.

Higher rpm's on the tach wouldn't necessarily indicate a BB car as SB L79 were high revvers.

 

[BarryK]

Higher rpm's on the tach wouldn't necessarily indicate a BB car as SB L79 were high revvers.

so were the L76 365hp cars

 

[mcditalia]

I agree with Barry,

Documentation is the sure thing to know if you have an original BB car. A lot of things can be duplicated/created to make a fake BB car from a SB car. Since the original build sheets are long gone, I can't think of anything on a car that would indicate the "smoking gun" to identify a BB car that can't be easily duplicated. Anyone else think differently?

 

[Subfixer]

To answer several of the same questions, The indent was on all 65-67 frames. The indent is to allow clearance for the balancer/pulleys on a BB due to the engine's increased length. 63/64 was not available with a BB so no indent was necessary, although I have seen examples of the indent added to install BB's into these earlier cars.

 

[BarryK]

I agree with Barry,

Documentation is the sure thing to know if you have an original BB car. A lot of things can be duplicated/created to make a fake BB car from a SB car. Since the original build sheets are long gone, I can't think of anything on a car that would indicate the "smoking gun" to identify a BB car that can't be easily duplicated. Anyone else think differently?

yep, the problem is that if someone who knows what the differences are and is willing to take the trouble to change them, it could easily pass as an original BB car.
Take '67 L88's. of the 20 that were actually originaly produced, only 36 documented cars are known to have survived.

 

[BarryK]

Mark
to most DIRECTLY answer your questions your best bet would be to get some of the NCRS judging manuals. I have the '65 Judging guide and could go thru it and list all the differences between '65 SB cars and '65 BB cars, but '66 and '67 will have some differences from '65.
If you are looking for info just to educate yourself than the judging mauals would be your best place to start I think.
i'm not trying to blow off your questions, but to list ALL the differences from each year '65-'67 between SB and BB cars would be a very long list.

 

[IH2LOSE]

Sorry but with out documents there is no way to tell if the car is a bogus big block and even then the docs could be bogus.

If you check the archives here there is a very detailed list that was made a couple of years back. I have a check list at home some place.

I went and looked at a car last year or the year before for a person I met at a car cruise,He was just looking for another option on a car that was proposed to be an original Big block car.

The owner of the car was a shadey fellow and while inspecting his car I question him several times with direct questions. Did this car leave the GM factory with a big block in it? He gave an answer like "the proof is in the pudding" That was a yes or no answer and he avaided it. Next quetion was did you install this motor in this car to replace a different motor ? His answer was like "I wish I had that kind of time" Need less to say you could tell the car was never off its frame and I really thought the owner was a crook.It had a big block fuel line and I know there is no way to replace that with the car on frame. I started to folow the fuel line back with my hand and sure enough under the batter tray was a hidden braze conneting the front part of a big block fuel line to the original small block fuel line.The guy freaked when I question him on it ,and explained he was going to point that out to me as he explained it must have rubbed thru and some one repaired it. I showed him it was a swedged fitting and soe one treid to fake a big block fuel line.To make a long story short we passed on the car

 

[BarryK]

I started to folow the fuel line back with my hand and sure enough under the batter tray was a hidden braze conneting the front part of a big block fuel line to the original small block fuel line.The guy freaked when I question him on it ,and explained he was going to point that out to me as he explained it must have rubbed thru and some one repaired it. I showed him it was a swedged fitting and soe one treid to fake a big block fuel line.To make a long story short we passed on the car

good catch Larry!
he must have been p*ssed at you for catching him in his lies.
nothing like being an educated buyer.

 

[Kid_Again]

IH2LOSE is right on

You will never REALLY know unless you have the original documentation.

Some tell-tales are hood prop on the wrong side, higher RPM tach (standard on all high perf sb/bb's - but for example, the L36 390hp 427 has a lower RPM tach so that really doesn't help much), 80lb oil gauge, square half shaft retainers.

The fakes are really, really good. Correct broaching marks on the block, correct font on the fake engine block numbers, block casting numbers ground off and new ones epoxied on. Amazing how much time some people have.

And, be especially aware of that "correct" big block '64!!

If you really want a big block car, buy a NOM car, drop in a crate 454 and have some fun.

 

[MarkM]

Thanks everyone. Sounds like I just need to continue to get educated - and that checking in here is invaluable.

So, I assume the bb fuel line is larger?

Mark

 

[Kid_Again]

No, I think the supply line from the tank is the same. At least, the line on my '65 sb is the same as my '66 bb and I haven't seen posts to the contrary.

 

[MarkM]

Thanks to IH2Lose. I checked the archives, but can't find anything. If you come across the list I'd appreciate a copy - or directions on where to find it. I think I'll pick up the Judging manual too.

Mark

 

[JohnZ]

It's NOT a big deal to convert a small-block car to a big-block car and do it well enough that almost no one would ever tell the difference, and professional restorers do it all the time (and so do amateurs, but they usually miss things that give it away). Now that BB prices have gone out of sight, I wouldn't pay a BB price for a car without comprehensive documentation, and most of that can be faked now too.