small block 400 (1 Viewer)

[hippi68]

i am getting ready to install a 400 small block in my 40, i have heard they have heat probs due the siamese water jacket around the center cylnders. i was wondering if anyone else who has done this swap has had any heat troubles when they get to romping around.

thanks !

 

[Degnol]

400 sbc--overheating myth? - The Forums at Chevy Talk



Good read.....

 

[HappyGilmore]

I had a 400 in a 1979 Malibu for years and had no problems with it. Just make sure you are using an appropriate radiator with your FJ and you should be fine. My only problem was sitting at stop lights or extended idling would it start to warm up. This was due to the mechanical fan being too small with a crummy shroud, not the engine. Good luck.

 

[dgangle]

X2 to Happy. 265F plowing wet heavy snow with old 3-core rad, solid fan and no shroud. Hot, hot, hot.

 

[hippi68]

kool, thanks for the replys. the link i think answered my questions.

 

[inkpot]

400 sbc--overheating myth? - The Forums at Chevy Talk



Good read.....

Howdy! One guy (Vaughn?) pretty much nailed it. Putting heads from any other small block on it blocked the steam vents that are positioned between the bores on the block. Poor maintenance allows rust/crud to block these same holes. Cheap head gaskets may not have these holes, so it needs to be double checked when installing heads. Non 400 heads may be drilled for the steam vents by using a 400 head gasket as a template. Bigger engine can create more heat, so cooling system design is more important. Heavy radiator, good shroud, big fan, hi volume water pump, supplemental electric fan can all help to prevent problems. I would not hesitate to use a 400 sbc. John

 

[HeadCase]

I had severe heating problems with a stock 400 sbc in my wheeling-built 40. Could not solve them through bigger rad, electric fan, etc. Ended up selling the engine and going to a tbi 350 - best move I ever made. Would not/not recommend this powerplant for a wheeler.

 

[hippi68]

headcase, did you ever check to see if your steam vents were cloged up with rust/gunk ?

if so, then i just have to hope i don't have the same prob. pretty much moved beyond the point of no return.

 

[HeadCase]

No, I never pulled the engine apart - the ports could have been plugged. It honestly wasn't the engine I wanted for what I use the rig for, and had a great local shop to work with (props to Iron Pig Off Road - great folks). I also wanted the GM hi po serp system, which does not fit on the 400.

At any rate, you'll have fun, and good luck with your build. PM me if you think I can help.