small block 400
 

Anybody know much about the 400 small blocks? A guy gave me a standard bore complete motor but I don't know to much about them. Thanks.

Re: small block 400
 

They are externally balanced, other than that, not much different about them. If the block is good build it!

Re: small block 400
 

Build it you'll love it.

Re: small block 400
 

Is it 2 or 4 bolt? The 2 bolt 400s are stronger than the 4 bolt blocks
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Re: small block 400
 

I'm pretty sure he said it was a 2 bolt but haven't pulled any numbers off it. He said it ran fine when pulled so who knows. The guy is into those dirty F word cars and trucks and said he'd never use it so he just gave it to me!

Re: small block 400
 

As others have said the 2 bolt in this case is more desirable than the 4 bolts. The 509 casting is the cats meow.

Re: small block 400
 

Great engine. In addition to the external balance, the cylinders are siamesed, and the heads need to have steam holes, but you can take a 350 head (like a vortec) and drill them.

They are less forgiving than some if they're overheated, so make sure your cooling system is up to snuff.

Re: small block 400
 

Huh? Now you're talk'n a foreign language! LOL! Thats what I heard years ago that they had overheating problems. Does the machine shop do the drilling on the heads?

Re: small block 400
 

no machine shop needed. Just a 1/8 inch [I think] drill bit. just place a new gasket on the head and that will give you the location to drill. If I remember it is 4 holes, very simple you should be able to find a write on it on the net

Re: small block 400
 

They have a longer stroke,so they make great torque. It's a 400 crank that is used for 383s built from 350 blocks. I never experienced any overheating problems from a standard bore. It's when they are over bored,which is limited. With a healthy cooling system there will be no problems. They make great drag motors bored into 406s and up to 427.

Re: small block 400
 

WOW!!! Great score! Build it mildly for a street motor or build it wildly for a street/strip motor but either way I think you're gonna be very pleased with it. They're torque monsters!!! I've got a 1509 400 that I plan on building this spring for my '96 S10. Keep me in mind if you decide you want to "Not Fool With It" lol.

Re: small block 400
 

If your cooling is up to par like radiator, good cooling fans you will not have problems. I have a 406 with aluminum heads making 500+ horses and i never have a overheating problem. In 95 degree weather this summer mine ran around 185. My brother drag races and has 3 406 motors and has no problems.These 400's are torque beasts. Be prepared...lol:lol:

Re: small block 400
 

He gave you a 400 for free.......you lucky dog! 400 got a bad rap about overheating, they are no worse than any engine. Change to a longer rod when you rebuild and overbore to .030 and never go more than .040 on a street 400.......hmm does anyone make an off the shelf .020 over 400 piston? Check out this months Car Craft Mag, Jeff Smith just redid a 406 SBC that make 500 Lbs/ft with Vortec heads.

I actually have a brand new GM 400 block in my garage that I don't what to do with it.

Re: small block 400
 

If you lay a 400 head gasket on a 350 head, you will see some small holes next to the web between the cylinders. Those keep steam from building up on the 400. You can drill them with hand drill, or any machine shop will know what to do.

Overheating with the 400s is misunderstood by a lot of people. The 400 isn't any more likely to overheat than a 350 or any other SBC. The 400 is less tolerant of overheating than other SBCs, if it does overheat, because of thinner walls in the castings.

It's a great motor and I'd take it in a heartbeat. Make sure you use the right balancer and flex plate.

Re: small block 400
 

[QUOTE=406 Q-ship;4953178...


.....hmm does anyone make an off the shelf .020 over 400 piston? .

[/QUOTE]


I got mine from Keith Black for my 350 con rods

Re: small block 400
 

Just take your time and do it right and you will be pleased with the 400.

Re: small block 400
 

There ya go! Heck,has no one ever roached a 350? I believe a 400 can run cooler,if anything,when driving along normal (who does that,right?) due to the torque they make and less throttle demanded. They work effortlessly where a 350 needs a slight push. They are great in the trucks. GM should have offered these. I had a stock one in a K/20 and it was an ideal motor. It got 12.5 mpg with 4.10s and 12.50/35 rubber. Never broke a sweat.

Re: small block 400
 

I've built several and have one in my `70 C20 now. I love them. I've towed campers and driven in the heat out west with no problems. I have the 4 core desert cooler. With over drive and a properly tuned carb I've had 16-17 mpg at 65 mph. It's easy and you can do it at home. You'll love the engine.


http://www.crankshaftcoalition.com/w...ck_Chevy_heads

Re: small block 400
 

Great engine. Used to be worth a mint, but due to the increasing popularity of lsx, they are not as valuble as once were.

I have a .040" over 509 casting that is going in my iroc.

Re: small block 400
 

just built one with vortecs dished pistons and a crane 274 cam should be nice cant wait to fire it up this week gotta go to the Redskins game tomarrow HTTR

Re: small block 400
 

Thanks for all the tips and ideas. Kinda excited about the 400 now. Any year recommendations on the year of vortex heads to use or are they pretty much the same as the old school heads? :flagw:

Re: small block 400
 

Do some research, You can get brand new vortec heads from summit for about 650 bones yes theres difference between summit/dart 'vortec' heads and true GM vortec heads

Re: small block 400
 

Yes, buy your vortecs new, from summit, jegs, scroggin dickey, pace performance, etc... Don't waste your money on junkyard heads.

Re: small block 400
 

I just picked the motor up from the guy and it is a 509 casting. Sweet! No holes in the block, pan or anywhere else except where they're supposed to be. Oil looked good too. Start tearing into it tomorrow and start looking for some heads!
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Re: small block 400
 

When you take the heads off check for cracks between the bores and steam holes, it is fairly common if it has been run hot at some time in it's life.If no cracks rebuild it with good heads like the vortecs or my fav the AFR heads and enjoy.Also they like alot bigger cam than the 350 does.Have fun.