Tonawanda small block?

[bergy]

The "conv" designations were permanently part of the patterns when they were made. They reflected the planned casting conveyor when the pattern was made (could have been years earlier). They were not "tags" like the date codes & didn't represent which line the mold was actually made on. Remember the rule of thumb - iron patterns (which these were) typically lasted 100,000 molds before refurbishing. Aluminum patterns lasted 10,000 molds. Your block was cast off of pattern #11 in that family of patterns - which could have been in production for a long time.

the casting lines were

Line 1 - M4 Blocks

Line 2 - small blocks

Line 3 - M4 heads and all intakes

Line 4 - small block heads

Line 5 - water pumps, oil pumps, bearing caps, & misc. lower volume parts

Line 6 - same as line 5

Line 7 - was removed in early '60s

Line 8 - all brake drums

[novadude]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bergy</div><div class="ubbcode-body">The &quot;conv&quot; designations were permanently part of the patterns when they were made. They reflected the planned casting conveyor when the pattern was made (could have been years earlier). They were not &quot;tags&quot; like the date codes &amp; didn't represent which line the mold was actually made on. Remember the rule of thumb - iron patterns (which these were) typically lasted 100,000 molds before refurbishing. Aluminum patterns lasted 10,000 molds. Your block was cast off of pattern #11 in that family of patterns - which could have been in production for a long time.

the casting lines were

Line 1 - M4 Blocks

Line 2 - small blocks

Line 3 - M4 heads and all intakes

Line 4 - small block heads

Line 5 - water pumps, oil pumps, bearing caps, &amp; misc. lower volume parts

Line 6 - same as line 5

Line 7 - was removed in early '60s

Line 8 - all brake drums </div></div>

Great info. Its always fascinating to learn how they actually built these things (to me, anyway).

[red67]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bergy</div><div class="ubbcode-body">The &quot;conv&quot; designations were permanently part of the patterns when they were made. They reflected the planned casting conveyor when the pattern was made (could have been years earlier). They were not &quot;tags&quot; like the date codes &amp; didn't represent which line the mold was actually made on. Remember the rule of thumb - iron patterns (which these were) typically lasted 100,000 molds before refurbishing. Aluminum patterns lasted 10,000 molds. Your block was cast off of pattern #11 in that family of patterns - which could have been in production for a long time.

the casting lines were

Line 1 - M4 Blocks

Line 2 - small blocks

Line 3 - M4 heads and all intakes

Line 4 - small block heads

Line 5 - water pumps, oil pumps, bearing caps, &amp; misc. lower volume parts

Line 6 - same as line 5

Line 7 - was removed in early '60s

Line 8 - all brake drums </div></div>

Is this mold, T11, only used for casting 352 as the casting number is also not a tag? Mold T11 for casting 352. My understanding is that casting 352 was used for 327 and 350 in 1967 only so this block could have had a very limited production run. Alvin Colvin in his book states that he is not sure when this casting was used and thought it was a limited run used late in the model year but the September 1966 casting dates are wrong for that. I believe that Tonawanda stepped up small block production in the fall of 1966 because there was a shortage of the new 350 engine then. In the fall of 1966 you could not buy an over the counter 350 engine or parts. You could only get a 350 engine via warranty and a serial number had to be provided to the parts system. This is stated in GM docs from the era.

[red67]

Thanks for the good info. I always wondered what these numbers meant but nobody to date has been able to give me the specifics. The intake and heads are also Tonawanda.

[bergy]

That pattern, T11, would only be used for the part number on the cope. &quot;T&quot; is for Tonawanda MCP and it's the 11th pattern in that series. It's possible to have other &quot;T11&quot; patters in another series of blocks. The part numbers were not changeable &quot;tags&quot; like the date inserts were.