Ok, yet another thread related to building a street 350 for power/performance :lala: :lala:

How do you know what block to use, is there a certain set of casting numbers that are better, like with heads? Does it make a difference as far as boring it out, making a stroker, etc, as far as choice of blocks?

And what are the pros and cons of iron blocks vs aluminum ones, and which is the better value?

 

if it were me i'd be looking for a roller block with one piece rear seal

 

Any 350 Chevy block can be used for a street / strip build up. You just have to make sure the block is in good shape, and a machine shop will do this before they bore it etc.

That's why I am a fan of buying a COMPLETE, RUNNING engine to start with.

67-86 350 blocks were 2 piece rear main seal
87-later are 1 piece rear main seal

You can't mix flywheels or flexplates between the two different styles.

87 and later require a different balancer than the earlier blocks.


Alum blocks = BIG $$$$ and "look at me" status
Iron blocks = cheap, plentiful and durable



I recommend doing a web search for David Vizard. Buy several of his Chevrolet engine books and start reading....it's WELL Worth the price and time.


HTH

 

First off theer are 3 types of 350 blocks-

2-bolt
4-bolt
and roller blocks

2 and 4 bolt blocks are pre 87 with a 2pc rear main seal. 4 bolt is strnger bout a 2 bolt block can be drilled and tapped for splayed mains. splayed mains are stronger but that is more $. All came with flat tapped lifters but retro fit roller cams are every where. Blocks with a 010 a 020 or both cast underneath the timing cover have higher nickle and tin contenst and are stonger castings.

Roller blocks are 87 up and have a 1pc rear main seal. Someone correct me if i am wrong but I believe all are 4 bolt main. Most cam with roller cams and all should have the provisions for a roller cam with factory lifters and retainer. They also cam with a cam retention plate.

As for wih block you go with it is up to you and what you can find. all will work well.

alum blocks generally aren't worth the cost.

 

very few roller one piece rear main seal blocks are 4 bolt