340 vs ta 340

[Daz570]

Can anyone out there please tell me what the difference in block is from 340 (2780930 casting) and ta 340 (3577130 casting) and what the number on the end signifies? eg 2780930-340-6




Thanks,

Dan.

 

[j-miller]

I'm not an expert on it but I remember hearing the T/A blocks being 4 bolt mains. I could be wrong.

 

[70aarcuda]

T/A blocks came with thick webs in the cranks area for 4 bolt mains...
but from the factory they were 2 bolt mains.

 

[Alaskan_TA]

Yep, thicker main webs on the T/A bocks for a more rigid bottom end & more meat to allow for 4-bolt mains if desired.

The number at the end (in this case a 6) is the core revision number. It means that the mold your block was cast in had been 'revised' 6 times to correct core shift.

 

[Max340]

ALso, the pan rails were supposed to be "filled". If you take your finger on most LA blocks, you'll find it hooks nicely on the back side of the pan rail. the T/A blocks were supposed to be filled in for better stiffness.

 

[Daz570]

are there any stories of the basic blocks failing in any serious way?

I'm about to do a repair on a basic 340 (has been frozen and cracked in the valley) just curious if i should be looking for anything else before attempting this, or, whilst it's baked and welded, are there any weak points that could be re inforced?

Dan.

 

[nothingbutdarts]

are there any stories of the basic blocks failing in any serious way?

I'm about to do a repair on a basic 340 (has been frozen and cracked in the valley) just curious if i should be looking for anything else before attempting this, or, whilst it's baked and welded, are there any weak points that could be re inforced?

Dan.

Bummer, I ruined one of my 340's in the valley the same way. I feel like a fool. The valley just split apart when it froze. I never thought about getting it fixed. Of course it was like 1976 or 1977 when I did this. I hope it works for you.