hey guys i just ran my casting numbers on the 350 i got for my camaro...i was just wondering what kinda power i can expect from it since the site i used was very vague...the number is 25GM3970010, and if my source was correct it was used in 68-79 for trucks/high perf. applications..it does have a double roller timing chain and 4 bolt mains. does anyone know more about it? i dont have any info on the heads, however.

 

3970010 is a very common 4" block all through the 70s. They came with both 2- and 4-bolt caps installed in them; some came in trucks, some in various cars, etc.

It's impossible to guess what kind of power you'll get out of it, because the block has very little to do with that. Heads, cam, and pistons are mostly respnsible for that. A block is a block is a block as far as that goes.

 

yea the site said i could be making anywhere between 140 and 375 horses...i really need to get the head casting numbers too but i cant find them

 

Right... and don't forget, those ratings aren't apples to apples; some are the old 60s "gross" HP, some are the 71-up "SAE net".

The enormous majority of places I've seen those blocks were L48 and the like; 175-180 HP 350 4-barrel. Garbage heads. But, the block is still perfectly good as far as being a block, you just usually would have to get some better heads.

 

A block is a block really... some were used on 150hp engines, some on 450hp engines.. same blocks.

My '79 350 (Z28) block is the same as yours.

 

yea i got the head casting numbers today...its the 624 heads, which are basically the 882 heads but lighter i think....i think i just have a smog poo poo 350