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TA rocker question.

spoolinhard

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I'm looking at a TA longblock. One of the rocker arms is missing. The owner suggested that this is not one of the offset rockers and could be sourced from a regular 340. Is this true?
Pic:

IMG_6844.jpg
 

floyd

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No, regular 340 rockers are not adjustable and are completely different. You’ll need to find a correct 340-6 replacement.

Here’s a good reference pic

2C84A2BE-C118-4615-A7AB-324778E98F1F.jpeg
 
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gzig5

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I think the exhaust rockers were just regular straight ones, same as used on the 273 motors with solid lifters. 340's used stamped rockers, which would theoretically work if one would fit on the shaft. The distance from the shaft to the ex valve was the same. I have some straight adjustable ones if you need to buy a single.
 

spoolinhard

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I think the exhaust rockers were just regular straight ones, same as used on the 273 motors with solid lifters. 340's used stamped rockers, which would theoretically work if one would fit on the shaft. The distance from the shaft to the ex valve was the same. I have some straight adjustable ones if you need to buy a single.
Should the deal go through, I will take you up on that.
 

gzig5

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Wrong. The 273 rockers are different. The 340 T/A rockers are stronger made to deal with high rpm, heavier springs.
Maybe, I dont' know. But I know that 273 rockers have been used on plenty of 340/360 builds making 400+hp with no ill effects. I'd bet many of those cams had more spring than the original TA motors.
 

moparleo

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Mopar says different. But if you are trying to build a higher horse/torque motor, why use stock iron rockers anyway. The after market has NEW not 50 year old parts that are without question better quality and stronger. If this as a stock, resto build I can see using stock parts. But it is his money. The stock rockers for a 273 and a T/A 340 are definitely not the same. Someone will always say that they know someone who did something or other and didn't have a problem. Not everybody gets the Covid-19 flu either but that doesn't mean not to be careful just in case.
 

spoolinhard

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The deal went through, and I own the complete long block minus one rocker. I can tell you with 100% certainty that the 273/ 340 TA rockers are different
 

fk5aar

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The offset rocket heads for TA are worth double to triple the money also
 

fastmark

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You are correct that 273 and TA rockers are not the same, however, I had a bud who bought an AAR years ago. It had the TA heads and six pack but a regular 340 block when he got the car. For some reason, it only had the offset TA rockers and all the straight one were stock 273. It worked fine for many years with no problems, so it can be done.
 

Cuda Hunter

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Spoolinhard, Would you be willing to share the vin stamp on the block you have purchased?
Congrats on finding an aar motor! Hard one to find. Good price?
 

moparleo

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Another " I had a friend and it worked for him" story. Why don't you just agree that it is not the ideal set-up or the factory would not have spent the $$ on R & D to develop the T/A rockers. You can use all kinds and brands and countries of different origins parts that will " work". If it wasn't your money, and it isn't, wouldn't you prefer to use the "correct" parts that were designed for the engine rather than parts that will just "work" ? When you shop for things do you look just for stuff that "works" or what does the best job for your budget or needs?
As the owner verified after he acquired the motor, the T/A parts are definitely not the same as 273 parts. That should settle it.
Always use items that were designed for a specific item and not just what will "work". Congrats again on the T/A motor. A real piece of automotive history, and something that many of us would love to possess .
 

fastmark

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Some people just have to complain about everything. I said it worked just fine. I did not say it was the exact correct piece. I worked on the car and even owned it for awhile so you could say it even worked for ME. I’ve got set of of 273 rockers on my AAR right now because I have regular 915’s on it and the original TA heads are off. I regularly shift at 6500 rpm with no ill effects. You need to remember that this rockers were designed for the RACE trans am cars. They would have been overkill for the street. SO, in a pinch, you can use a straight 273 rocker. Is it 100% correct? No. Chances of finding just one rocker will be slim. Somewhere I’ve got a set of unmachined W2 rockers. Both straight and offset. I’ll look to see if I can find them and compare them to the straight oem TA rockers I have. If you can find some one to machine it, I’ll give it to the OP.
 
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