Has anyone had any sort of luck when it comes to running a block that has the pass side rear mount/dowel area broken? My car shook like crazy, when I bought it years ago it wasn't running and may have very well saved the car. Dave at ATI spun the 10" converter that was in the car and found it to be 30 grams (about an ounce) out of round. Long story short I have a new 10" ATI converter, new flex-plate, ARP bolts for plate and converter. The trans was rebuilt including a new pump and bushing kit, also has a bolt in sprag all done locally by Will that runs the Ornery Cuss 72 Dart race car that has been around Pa for decades. It's taken 6 months to get everything rounded up/paid for and I for whatever reason missed the fact that the factory alignment dowel is completely AWOL. The dowel hole that you see in the pics was obviously added to the block and trans. The pin was pushed through the back side of the trans so when the two were mounted up the first time back in 83 they didn't make sure both pins were doing their job.

What next? Risk 2k worth new parts and a trans rebuild, or who knows how much to replace a solid 340 that runs great but is missing a key component? I'm torn but leaning towards taking my chances with what I have. The car wont be raced, and if it's driven over 500 miles a year that'd be a lot even with a 180 mile round trip to Carlisle. Thanks in advance, TC.

Also I'd like to add that in the event it would cure alignment issues I'm not afraid to use a mid-plate on the car and use spacers for the converter. I'm aware nothing about this is ideal but if I had to guess I would say the converter issue was due to neglect or even being a 'great deal' piece that should have been never been put in the car 30 years ago.

Here's a link to my last posts about the car and trying to troubleshoot from September: older post

All I can add is I just came from the tranny shop where they are setting up my gears & the owner was talking about a recent case where someone used an adapter (didn't get all the specifics) but a locating dowel was missing & it all fubared.

I have two 340 blocks like yours, one is .040" over and the other is .060" over. Both of mine are going to the scrap yard.

If the dowel holes are intact. I'd run it.

The other bolts are nothing more than fasteners to hold the engine and transmission together. The dowels take ALL the shear load.

Y'know for all the trouble and expense of fixing the block I think he'd be better off just machining a replacement block. Welding a cast iron block is no easy task, won't be cheap and will never have the original strength. Unless its a rare numbers-matching car, I'd seriously consider replacing the block.

This is not a rare numbers matching car just simply a 340 'cuda with a 69 340 in it. As you can see dowel pin that's been drilled in the block and trans clearly isn't stock. The outline of the original dowel location can be seen just below it. I was tempted to put the original dowel in the trans, then lift up to seat it in the broken area and see if the hole that drilled for a new dowel would actually line up. Basically at this point I have the option of trying to limp along with the 340 or installing a 318 because I'm not in a position to spend 3 - 4k to get a 340 built.

I had a block like that and I ran it but I had to mess with the alignment as it would vibrate. The only reason I did it though is it was a T/A block in an AAR cuda. Otherwise I would have scrapped it. I think you should be able to get a good used short block someplace for way less than $3-$4k and buy gasket kits and swap your heads and other parts. You could clean and paint everything real nice while you are at it.

Surely will get flak for this, but here goes ...

How about converting one of the other bolt holes into a dowel location?

That way there would still be 2 dowels to locate, just 2 fewer bolts holding things together.

I knew a guy years back in Vt who rebuilt TFs, and had a 67 RT personal car. When someone wanted a beefed 727, he would sell them the one out of his car. Got to be that he only used a couple or 3 bell bolts, 2 crossmember bolts, and I think only a couple converter bolts, could pull the trans in a few minutes.



This would make the 2 lower block to trans braces more important.