helicoil in heads

fishy68

You actually answered your own question and then headsbikesmopars gave the answer, also.

the question is:

(don't ask me why Ma Mopar used the same # for different heads)

The answer is:

The only difference was in the machining of the heads for the TA engines.

The reason is:

They didn't have to change the castings to make the T/A heads because the difference was in the machining. Castings are expensive and it is not worth spending the money for new molds if you don't need to - especially when you are only making 5,200 x 2 of the parts.

You just use the existing (already paid for casting) and machine them different. **You don't need new castings.**

It's the simple cost/effort issue we make everyday. Why spend the time and money do something if you don't have to?? It also makes it possible for the working man to afford.

Another question I see asked alot and have an answer for is:

**Why is 360 casted on my 340 head?**

The answer is:

After they made the 340 castings and ran them in production, they probably found some things they wanted to change. Either for improved performance, manufacturability, problems that weren't caught before production started, or changes needed for new products. It is not possible to make these changes to the parts because you need to use them to make parts every day and don't have time to send them out.

So when the new product comes along (ie. 360), you get the opportunity to make a new tool/casting and change the parts without stopping production. (This means time to make the tool and the money allocated to do it.)

You can make the changes to the new tooling without taking the current tooling out of production and bring it into production early so your current product can benefit from the changes also.

** In short, they made changes to the head casting for the 360 and released them early on the 340. So they changed the number cast on the head because it was paid for with money allocated for the 360 program. It keeps the company executives and accountants and the government off each other's backs. **


Steve the 915 casting number is used for the 1970 TA head and non TA heads made from 70-72 (don't ask me why Ma Mopar used the same # for different heads) but the TA heads are different because they have offset intake pushrods to allow more intake port opening. The other 915 heads are the same casting design as any other small block LA head. I noticed yours have the offset pushrods and rockers which makes them the TA heads.

Quoted by fishy68 *-


the TA heads are the 'J' 915 castings and are the same as any of the 915 castings. The only difference was in the machining of the heads for the TA (six-pac) engines.

Quoted by headsbikesmopars *-