Distinguishing between Tonawanda and Flint block
09-05-2005, 06:13 PM
#1
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Distinguishing between Tonawanda and Flint block
If you have a block (small block) that has been surfaced (numbers on pad are gone), how can you tell if it was a Tonawanda or Flint casting?
09-05-2005, 06:28 PM
#2
Don't hold me too it but I think you can tell a Flint block by looking for the plug you see in this picture. It's just above the water pump on the passenger side.
http://www.pbase.com/valrico4/image/48777641
http://www.pbase.com/valrico4/image/48777641
Last edited by valrico4; 09-05-2005 at 07:06 PM.
09-05-2005, 08:48 PM
#4
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That's the kind of info I needed. I KNEW there was some kind of way to tell a Flint from a Tonawanda block other from the stamping on the pad.
09-05-2005, 09:14 PM
#5
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Maybe one of you can answer me.
Is that plug the last vistage of the remote/add on oil filter they had back in '55?
I had a '56 BelAir and don't remember it having an oil filter at all.
Is that plug the last vistage of the remote/add on oil filter they had back in '55?
I had a '56 BelAir and don't remember it having an oil filter at all.
09-05-2005, 10:10 PM
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In the beginning, when God created the heavens and earth-----------------------oh no, that's another story.
In the beginning, when the 55 V-8 was introduced, as you obviously know, the oil filter was an ACCESSORY and mounted on top of the intake manifold. That plug is where the oil source came from to supply the the filter. The 55 manifolds had a similar plug on the RIGHT side of the manifold, between the exhaust crossover passage and the runner for an intake port. This is where the return oil was dumped from the filter into the lifter valley.
Since that time, all small blocks have been cast with a PROVISION for this front oil passage in the block. Some blocks got the passage drilled down to the center oil galley (you can readily see this angled boss at the front of the lifter valley when the intake manifold is off). Some blocks did not have the passage drilled. If you take a look at a block that does not have a plug there, you will notice that there is kind of a flat place where the hole could be drilled/tapped. LOTS of later engines, particularly SB400s, did not get the passage drilled. For one reason or another, I have personally drilled/tapped this passage BEFORE sending the block to the machine shop, thus, any metal particles get cleaned out when the machine shop vats the block. This front oil passage was used in many large truck applications for providing oil to such truck application accessories as the compressor for air brakes. It makes a good source of oil to supply a turbo charger as well as a good place to screw in a SMALL oil gauge (like you sometimes see screwed into motorcycle engines). I have a gauge screwed into the SB420 in my boat. Lets you see true engine oil pressure at a glance!
Also, some Olds engines have a front oil passage similar to the SB Chevys. I have a Cutlass with an Olds 455 and I have installed an oil gauge right at the front of the engine.
Also, to answer your concern about 56-later oil filters, ALLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL SB engines, starting with 56, got a filter at the left rear on the bottom of the block. The 56-later blocks were a totally different casting from the 55 block because of the addition of this filter boss. So, starting with 56, an oil filter was no longer an accessory, it was standard (also, the 55 oil pan is a one year only pan and WILL NOT fit any other SB, nor will ANY other SB pan fit a 55 block).
In the beginning, when the 55 V-8 was introduced, as you obviously know, the oil filter was an ACCESSORY and mounted on top of the intake manifold. That plug is where the oil source came from to supply the the filter. The 55 manifolds had a similar plug on the RIGHT side of the manifold, between the exhaust crossover passage and the runner for an intake port. This is where the return oil was dumped from the filter into the lifter valley.
Since that time, all small blocks have been cast with a PROVISION for this front oil passage in the block. Some blocks got the passage drilled down to the center oil galley (you can readily see this angled boss at the front of the lifter valley when the intake manifold is off). Some blocks did not have the passage drilled. If you take a look at a block that does not have a plug there, you will notice that there is kind of a flat place where the hole could be drilled/tapped. LOTS of later engines, particularly SB400s, did not get the passage drilled. For one reason or another, I have personally drilled/tapped this passage BEFORE sending the block to the machine shop, thus, any metal particles get cleaned out when the machine shop vats the block. This front oil passage was used in many large truck applications for providing oil to such truck application accessories as the compressor for air brakes. It makes a good source of oil to supply a turbo charger as well as a good place to screw in a SMALL oil gauge (like you sometimes see screwed into motorcycle engines). I have a gauge screwed into the SB420 in my boat. Lets you see true engine oil pressure at a glance!
Also, some Olds engines have a front oil passage similar to the SB Chevys. I have a Cutlass with an Olds 455 and I have installed an oil gauge right at the front of the engine.
Also, to answer your concern about 56-later oil filters, ALLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL SB engines, starting with 56, got a filter at the left rear on the bottom of the block. The 56-later blocks were a totally different casting from the 55 block because of the addition of this filter boss. So, starting with 56, an oil filter was no longer an accessory, it was standard (also, the 55 oil pan is a one year only pan and WILL NOT fit any other SB, nor will ANY other SB pan fit a 55 block).
Last edited by DZAUTO; 09-05-2005 at 10:20 PM.
09-06-2005, 11:57 AM
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Flint engines (Saginaw castings) have the hole and plug and Tonawanda engines (Tonawanda castings) don't due to different machining processes for an intersection in the front of the main oil gallery; Flint tapped the hole and installed the 1/8" NPT plug after gun-drilling to create the gallery intersection at the end of the hole. 
