I just bought an 85 350 4 bolt main truck motor, (guy at the junkyard says it was an 85 LG4) I thought it looked funny so I ran the numbers. But apparently it only has like 8.1 compression stock and something like 73 cc heads. I have a set of new aluminum L98 heads sitting around fully assembled. I plan on doing a compression test on the motor tomorrow. If I don't need to rebuild the engine...Would the 58 cc L98 heads work?

 

That's a lot of conflicting information there lol.

An LG4 is just a 305, 2 bolt mains.

If the heads on it really are 73cc now and it has only 8:1 compression, then you could run those heads provided you checked all the valve clearances and you'd bunch your compression up to the mid 9s or so.

 

Oops sorry, I didn't finish giving all the information. It was SUPPOSED to be an 85 LG4. But I ran the casting #'s and all my sources said it was a 350 4 bolt from an 85 truck. So it's not the origonal engine and I got a 350 sold as a 305
From what Ive read, the pistons are dished, so I should have no problems with the valve clearance right?

 

you will know if you can use the heads when you pull the old ones...

you should be fine though... as long as the pistons arent flattops without valve reliefs or domed....

go ahead and change the cam while you are at it... and the timing chain

later,
Chris

 

cool deal

 

Ya I plan on replaceing the chain with a double, and put in a diff cam