BB Springs??
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
BB Springs??
I've been finding signs that my car lived it's previous life as a big block. Found Th-400 trans kick down switch on gas pedal. (bought car with ST-10) Found differential yolk straps (instead of SB u-bolts) on half shaft U-joints. 454 trim tag on shift console. How can I tell if my front coil springs are heavy duty, and used for a big block in 72? # of coils? coil diameter? They are installed so I can't measure uncompressed height. Radiator is not original. Vin tag not readable. Are there other signs I'm missing???
Thanks guys
Edie
Thanks guys
Edie
Last edited by Silvr77; Feb 23, 2005 at 05:02 PM.
Senior Member since 1492
Joined: Aug 2000
Posts: 87,930
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
Originally Posted by Silvr77
I've been finding signs that my car lived it's previous life as a big block. Found Th-400 trans kick down switch on gas pedal. (bought car with ST-10) Found differential yolk straps (instead of SB u-bolts) on half shaft U-joints. 454 trim tag on shift console. How can I tell if my front coil springs are heavy duty, and used for a big block in 72? # of coils? coil diameter? They are installed so I can't measure uncompressed height. Radiator is not original. Vin tag not readable. Are there other signs I'm missing???
Thanks guys
Edie
Thanks guys
Edie
You should have a 9/16" rear sway bar too. BB hood? What's the red line on your tach?
Race Director
Joined: Apr 1999
Posts: 15,146
Likes: 477
From: NM
Originally Posted by Silvr77
Vin tag not readable.
But if you cannot read the vin tag, what does the title say? The 72 had the engine coded into the VIN.
tom...
Pro
Joined: Nov 2004
Posts: 531
Likes: 118
From: Atlanta area
You should be able to tell which springs you have by the diameter of the wire the springs are wound from. In '73, the wire dia for an L48 w/A/c is 0.61 in. with a green tag marked with MA.
The big block springs are made from .65 in. dia. wire. I don't know what the code is for the big block springs.
The big block springs are made from .65 in. dia. wire. I don't know what the code is for the big block springs.
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
Hello,
I read in a past issue of a Corvette magazine that some small block cars were modified to be big blocks. One of the items that they conversion missed was with either the Oil Temperature gauge, or the Water Temperature gauge. I cant remember which one it was, but there may be a difference in the temp. readings between big and small blocks. When I get home tonight I will see if I can find the article as a reference.
kdf
I read in a past issue of a Corvette magazine that some small block cars were modified to be big blocks. One of the items that they conversion missed was with either the Oil Temperature gauge, or the Water Temperature gauge. I cant remember which one it was, but there may be a difference in the temp. readings between big and small blocks. When I get home tonight I will see if I can find the article as a reference.
kdf
Team Owner
Joined: Jul 2004
Posts: 40,408
Likes: 792
From: Redondo Beach, California
Any chance of getting to the build sheet on the top of the gas tank?
Yes, look for the rear sway bars (only the BB's had them I believe- did the F41 SB suspension have rear sway bars?) and also at the tach...this might be a clue. (Although I think that some of the 454's may have had some pretty low performance looking tachs.)
The little tag on the console shifter indicating you have a 454 is not necessarily determinative. Back in the late 1070's you could buy these things from GM for a dollar.
Sometimes the BB's had different overflow tanks than the SB. Also the radiator shroud can be a clue also in some years. For instance, a (1968?), a 1969, and 1970 BB radiator shroud can not be removed in a straight forward manner. The small block shrouds are easily removed. Basically stated, the BB radiator shrouds were molded so that they slightly overlapped the upper control arm attachment rods. This overlap made them very difficult to remove.
The suggestion to measure the wire size of the front coil springs is really good. Measure them with a caliper. If you don't have a caliper, and you're asking these kinds of questions, then I would respectively like to suggest it's time to buy a caliper!! (I'm always happy when I find another reason to buy another tool!!)
Yes, look for the rear sway bars (only the BB's had them I believe- did the F41 SB suspension have rear sway bars?) and also at the tach...this might be a clue. (Although I think that some of the 454's may have had some pretty low performance looking tachs.)
The little tag on the console shifter indicating you have a 454 is not necessarily determinative. Back in the late 1070's you could buy these things from GM for a dollar.
Sometimes the BB's had different overflow tanks than the SB. Also the radiator shroud can be a clue also in some years. For instance, a (1968?), a 1969, and 1970 BB radiator shroud can not be removed in a straight forward manner. The small block shrouds are easily removed. Basically stated, the BB radiator shrouds were molded so that they slightly overlapped the upper control arm attachment rods. This overlap made them very difficult to remove.
The suggestion to measure the wire size of the front coil springs is really good. Measure them with a caliper. If you don't have a caliper, and you're asking these kinds of questions, then I would respectively like to suggest it's time to buy a caliper!! (I'm always happy when I find another reason to buy another tool!!)
Last edited by 68/70Vette; Feb 23, 2005 at 09:32 PM.
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
My 72 SB car has straps w/forged bolts instead of U bolts on the side yokes also. Also have a BB radiator and shroud, but don't have BB tach, rear sway bar. I think on some days during production, the assm ran short on some parts and it didn't hurt anything to go put more heavy duty parts on to keep the line moving. Why would elec kickdown switch be a clue for a BB? SB automatics have them also.
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Originally Posted by Jughead
You should have a 9/16" rear sway bar too. BB hood? What's the red line on your tach?
Eddie
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Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Originally Posted by Tom73
Okay......sounds as if you could have some serious problems
But if you cannot read the vin tag, what does the title say? The 72 had the engine coded into the VIN.
tom...
But if you cannot read the vin tag, what does the title say? The 72 had the engine coded into the VIN.
tom...
Eddie
.
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Originally Posted by 68/70Vette
Any chance of getting to the build sheet on the top of the gas tank?
Yes, look for the rear sway bars (only the BB's had them I believe- did the F41 SB suspension have rear sway bars?) and also at the tach...this might be a clue. (Although I think that some of the 454's may have had some pretty low performance looking tachs.)
!!)
Yes, look for the rear sway bars (only the BB's had them I believe- did the F41 SB suspension have rear sway bars?) and also at the tach...this might be a clue. (Although I think that some of the 454's may have had some pretty low performance looking tachs.)
!!)
I am familiar with the SB BB A/C no A/C overflow differences, but again....no overflow tank when I bought.
Rad & Shroud are not origin.
Looks like the only indicator I have left is to check the spring diameter.
Thanks for all your replies guys.
Eddie
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Originally Posted by Gage
My 72 SB car has straps w/forged bolts instead of U bolts on the side yokes also. Also have a BB radiator and shroud, but don't have BB tach, rear sway bar. I think on some days during production, the assm ran short on some parts and it didn't hurt anything to go put more heavy duty parts on to keep the line moving. Why would elec kickdown switch be a clue for a BB? SB automatics have them also.
Eddie
