heads 462624 - 78 350 -are these weak?

[wazzabie]

Any truth to this?

http://craig.backfire.ca/pages/autos/boxchevy/lightweight-heads

The number on my heads look like 462824. The are original to a 78 350 K5. If these are a weak design what year of truck should I be looking to replace the heads from?

I may have a blown head gasket so now would be a good time replace the heads.

 

[tRustyK5]

That's a new one on me, my 87 TBI heads have the same "scalloping" he talks about, but so do most every small block head I've seen.

I've never heard of sbc heads being especially prone to cracking, even after overheating.

Years ago I bought a brand new 88 GMC pick-up, and just out of warranty the heater core tank cracked and leaked very slightly. I ended up overheating it badly in summer traffic. Newish truck and I wasn't watching my guages, when I felt it run weird i looked down and saw the guage absolutely pegged. Those heads didn't crack, just needed .010" removed to get them back to true and flat again.

Rene

 

[4X4HIGH]

That particular casting number is a light weight casting that is known to crack. Those are the same heads as the "882" casting. Those castings were used on 350 and 400 engines from 1970-1985. You can look for the steam holes to see if they were originally 400 heads or not. That would be the only difference betweem 350/400

 

[max 02]

That particular casting number is a light weight casting that is known to crack. Those are the same heads as the "882" casting. Those castings were used on 350 and 400 engines from 1970-1985. You can look for the steam holes to see if they were originally 400 heads or not. That would be the only difference betweem 350/400

I have a set that are 333882, I haven`t looked for the steam holes but I have always thought the were off a 400. I have been saving them incase I wanted to rebuild them.

Are you saying they are not worth putting any money into them?
Or might they be ok.

 

[str8axle55]

I had a set of 624`s that were cracked.

 

[4X4HIGH]

I have a set that are 333882, I haven`t looked for the steam holes but I have always thought the were off a 400. I have been saving them incase I wanted to rebuild them.

Are you saying they are not worth putting any money into them?
Or might they be ok.

Actually, the "882" castings are a good flowing head BUT they are the light weight castings that are prone to cracking. As long as you keep the heat under control they should be ok to build since you've already got them.

 

[max 02]

Actually, the "882" castings are a good flowing head BUT they are the light weight castings that are prone to cracking. As long as you keep the heat under control they should be ok to build since you've already got them.

Thank you! If you say so then I will keep them...for the future.

 

[wazzabie]

I wonder if my 624 heads are cracked. When I ran a coolant presure test I could hear a hissing sound coming from inside the engine. I'm also getting a lot of white smoke from the exhaust.

 

[4X4HIGH]

I wonder if my 624 heads are cracked. When I ran a coolant presure test I could hear a hissing sound coming from inside the engine. I'm also getting a lot of white smoke from the exhaust.

That's a pretty good indicator you have either a cracked head or blown head gasket.