[taff2]

I welded up the weak open valley on an early '59 389 block, it is a weakness I believe, compounded by fitting lightweight ali intake manifolds. My 389 (turbo combo) block is still together, the engine made just under a 1000 hp, not a lot I know by today's standards, before I had to take it out because I forgot to put antifreeze in the engine - and the block cracked! I've repaired the cracks (front of the block just below the heads) and it pressure tested fine, it's sat there as a backup for the 'new' '59 block combo.
The new combo block will have a TIG brazed lifter valley this time, in an effort to reduce the amount of distortion caused to the lifter bores by the arc welding process. Pics are of the old 389 block with painted valley, and the other pics are of the 'new' 389 valley plates that I had laser cut from 6mm steel. This 'new' block will also have a mains girdle but I've modified the design a bit to make it stronger (even though there was nothing wrong with the old one- bearings and crank were all good. I'll update as I go along if anyone is interested.
I've

[Sirrotica]

Originally Posted by taff2

I welded up the weak open valley on an early '59 389 block, it is a weakness I believe, compounded by fitting lightweight ali intake manifolds. My 389 (turbo combo) block is still together, the engine made just under a 1000 hp, not a lot I know by today's standards, before I had to take it out because I forgot to put antifreeze in the engine - and the block cracked! I've repaired the cracks (front of the block just below the heads) and it pressure tested fine, it's sat there as a backup for the 'new' '59 block combo.
The new combo block will have a TIG brazed lifter valley this time, in an effort to reduce the amount of distortion caused to the lifter bores by the arc welding process. Pics are of the old 389 block with painted valley, and the other pics are of the 'new' 389 valley plates that I had laser cut from 6mm steel. This 'new' block will also have a mains girdle but I've modified the design a bit to make it stronger (even though there was nothing wrong with the old one- bearings and crank were all good. I'll update as I go along if anyone is interested.
I've

By all means please document it, always interested in Pontiac guys that think outside the box. That's a nice looking main girdle you're making to hold everything together without a skirted block to start with.

[taff2]

Originally Posted by Sirrotica

That's a nice looking main girdle you're making to hold everything together without a skirted block to start with.

That's the original girdle I made years back ,it works fine but I have another stronger one in the making, I want to really lean on this new combo.
The idea of the girdle is to emulate a skirted/crossbolted bottom end, which along with the welded in valley should strengthen the block substantially.