[Big Mouse]

I'm new to 400's & I could use some advice.

I have a 1970, 400 ci SBC. It is a 511 casting # with the 4 bolt mains. The engine was punched .030" and dished pistons were put in by the previous owner (years ago). Upon tear down, all the main bearings were severely worn except for the rear main bearing. The crank is rather deeply grooved. I belive the balancer to have spun on the engine (externally balanced). Rod bearings look fine. The engine was running rough/shacking at idle. The heads will be replaced (it had 882's on it) - most likely with the Scoggin Dickey Vortecs.

The cylinders walls have some cross hatching left, but the wear patterns match exactly what was described in this post (which leads me to believe it was not bored with a torque plate): 400 sbc

Is this worth saving?

The alternative to saving this engine is to build a 383. My end goal is to have a streetable 350 to 400 hp. Drivetrain will most likely be a TKO500, posi rear (gears TBD - currently 3.0's), standard street tires on my stock 15" rims.

Sorry for the long post. Thanks for any advice.

[Jmark]

Like I said in the other post, we're running a 60 over 400 and its fine. Doesn't even think about getting hot. I say build it!!! Providing the machine shop gives the go ahead after a good check over. You may even be able to punch it .040 if the bores are close enough and you're machinist is worth his salt.

[Big Mouse]

Originally Posted by Jmark

Like I said in the other post, we're running a 60 over 400 and its fine. Doesn't even think about getting hot. I say build it!!! Providing the machine shop gives the go ahead after a good check over. You may even be able to punch it .040 if the bores are close enough and you're machinist is worth his salt.

Gulp, .060"? I bet I'm looking at 0.040" if I keep this one.

Are you running a 2 or 4 bolt 400? Did you do anything special to the block? You know, splayed main bolts, partially filling the block, etc...?

I also don't know what the implications are to having it re-bored with a torque plate if it wasn't bored with a torque plate to begin with? Maybe it doesn't matter?

P.S. Nice truck JMark!

[Blazin72]

Originally Posted by Jmark

Like I said in the other post, we're running a 60 over 400 and its fine. Doesn't even think about getting hot.

A friend of mine had a GMC pickup with a 400 that turned out to be bored .060 over as well. He had been driving it for probably three years and never once had an overheating problem.

I agree with Jmark, if the machine shop says it's ok to use then build it. If you can't salvage the crank you can always buy a new one from some place like Summit or Jegs, the machine shop might even have a 400 crank ready to go.

[Jmark]

Yep, 60 over on a 400 is not a big deal. We did NOT do anything special. 2 bolt block. It's built up pretty good. World heads, 286 comp roller cam, and on and on.....Runs fine. If you decide to not use it,,, SEND IT TO ME!!!!!!

Mark

[IanRiordan]

My 30 over 400 doesn't get hot at 48 deg celcius with a boat on the back. Siamesed bores win at Daytona on hot days. 400 cooling is another urban myth.

[curtis73]

If you decide to not use it, don't scrap it. That is one of the more desirable marine blocks. 4-bolts are always good, and since we marine boys have a non-stop fresh supply of cool lake water, overheating is never an issue.