small block 400 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

denny5625 · 10-13-2011, 09:24 PM

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.

webfoot · 10-13-2011, 09:27 PM

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

gonnuts · 10-13-2011, 11:14 PM

Build it you'll love it.

**screaminchevypickup** · 10-13-2011, 11:46 PM

Is it 2 or 4 bolt? The 2 bolt 400s are stronger than the 4 bolt blocks
Posted via Mobile Device

denny5625 · 10-14-2011, 12:10 AM

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!

Average Joe · 10-14-2011, 12:18 AM

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

Camaro_nut2001 · 10-14-2011, 07:31 AM

Quote:

Originally Posted by denny5625

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!

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.

truckster · 10-14-2011, 12:54 AM

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.

denny5625 · 10-14-2011, 01:00 AM

Quote:

Originally Posted by truckster

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.

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?

hugger6933 · 10-14-2011, 06:11 AM

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

BADPURPLE70CHEVY · 10-14-2011, 09:55 AM

Quote:

Originally Posted by denny5625

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?

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

truckster · 10-14-2011, 01:22 PM

Quote:

Originally Posted by denny5625

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?

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.

**special-K** · 10-15-2011, 07:09 AM

Quote:

Originally Posted by truckster

...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...

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.

Beuford · 10-15-2011, 07:47 AM

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

**special-K** · 10-14-2011, 06:19 AM

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.

406 Q-ship · 10-14-2011, 12:49 PM

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.

**kwmech** · 10-14-2011, 01:26 PM

[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

BADPURPLE70CHEVY · 10-14-2011, 11:43 PM

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

OJ1988 · 10-15-2011, 08:48 AM

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.

Donnie Mabe · 10-15-2011, 11:34 AM

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

denny5625 · 10-15-2011, 11:55 AM

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?

oldblue1968chevy · 10-15-2011, 12:53 PM

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

OJ1988 · 10-15-2011, 01:52 PM

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

denny5625 · 10-15-2011, 03:37 PM

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!
Posted via Mobile Device
Posted via Mobile Device

Daves70 · 10-15-2011, 04:45 PM

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.

10-13-2011, 09:24 PM	#1
denny5625 Registered User Join Date: Jul 2007 Location: Kennewick, WA Posts: 152	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. __________________ 66 el Camino 70 1/2 RS Z-28 71 C10 2wd 72 2 wd Blazer (2) 72 4 x 4 Blazers 88 24' Mirage 70 mph+ 08 Harley Night Train 08 Silverado 4d 4 x 4

10-13-2011, 09:27 PM	#2
webfoot Registered User Join Date: Nov 2007 Location: Hermiston, OR Posts: 947	Re: small block 400 They are externally balanced, other than that, not much different about them. If the block is good build it! __________________ *Running in place gets you nowhere fast.* -me 1968 GTO 4-spd covnvertible 1970 K-20 4-speed, factory AC.

10-13-2011, 11:14 PM	#3
gonnuts Registered User Join Date: Sep 2010 Location: Langdon, Ab Posts: 348	Re: small block 400 Build it you'll love it. __________________ 67 Chev SWB, 400 SB .040 over, vortec heads, comp XE268 cam, performer EPS intake, edel. 650 AVS carb, 700R4

10-13-2011, 11:46 PM	#4
screaminchevypickup Laid Back Join Date: Apr 2010 Location: mcloud ok Posts: 2,658	Re: small block 400 Is it 2 or 4 bolt? The 2 bolt 400s are stronger than the 4 bolt blocks Posted via Mobile Device __________________ 72 chevy swb Direct dealers for.. Vintage Air, Porterbuilt, Billet Specialties,Budnik wheels ,eddie motorsports, raceline wheels, intro wheels, Dakota Digital, precision, unisteer, Trimparts, and many many more... Laid Back Recreations.. Full restoration shop and full paint and body.. Kyle http://67-72chevytrucks.com/vboard/s...d.php?t=574629

10-14-2011, 12:10 AM	#5
denny5625 Registered User Join Date: Jul 2007 Location: Kennewick, WA Posts: 152	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! __________________ 66 el Camino 70 1/2 RS Z-28 71 C10 2wd 72 2 wd Blazer (2) 72 4 x 4 Blazers 88 24' Mirage 70 mph+ 08 Harley Night Train 08 Silverado 4d 4 x 4

10-14-2011, 12:18 AM	#6
Average Joe Registered User Join Date: Feb 2009 Location: Southern Oregon Posts: 1,352	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.

10-14-2011, 12:54 AM	#8
truckster Registered User Join Date: Jan 2001 Location: Orem, Utah Posts: 7,982	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.

10-14-2011, 06:11 AM	#10
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	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

10-15-2011, 07:47 AM	#14
Beuford Registered User Join Date: Oct 2009 Location: Townville,Pa Posts: 284	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

10-14-2011, 06:19 AM	#15
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	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. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

10-14-2011, 12:49 PM	#16
406 Q-ship Registered User Join Date: Oct 2010 Location: Largo Florida Posts: 632	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. __________________ Lifes journey is not to arrive at the gate well preserved, it is to slide in sideways all used up and wore out yelling.....God what'a ride! Where patience fails, force prevails Stapp's Ironical Paradox "The universal aptitude for ineptitude makes any human accomplishment an incredible miracle."

10-14-2011, 01:26 PM	#17
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,650	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

10-14-2011, 11:43 PM	#18
BADPURPLE70CHEVY 406 Powered Join Date: Aug 2009 Location: waynesville,n.c. Posts: 877	Re: small block 400 Just take your time and do it right and you will be pleased with the 400. __________________ 70 GMC 68 c10 2002 silverado 72 4x4

10-15-2011, 08:48 AM	#19
OJ1988 Just a car guy Join Date: Feb 2006 Location: New Washington, IN Posts: 991	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. __________________ 1955 belair Blown Pro Street cruiser 1971 Camaro Pro Touring 1973 Vega Drag Car 1970 C20 tow rig

10-15-2011, 11:34 AM	#20
Donnie Mabe Registered User Join Date: Oct 2011 Location: Delta Pa Posts: 22	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



Register or Log In To remove these advertisements.

10-15-2011, 11:55 AM	#21
denny5625 Registered User Join Date: Jul 2007 Location: Kennewick, WA Posts: 152	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? __________________ 66 el Camino 70 1/2 RS Z-28 71 C10 2wd 72 2 wd Blazer (2) 72 4 x 4 Blazers 88 24' Mirage 70 mph+ 08 Harley Night Train 08 Silverado 4d 4 x 4

10-15-2011, 12:53 PM	#22
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	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 __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

10-15-2011, 01:52 PM	#23
OJ1988 Just a car guy Join Date: Feb 2006 Location: New Washington, IN Posts: 991	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. __________________ 1955 belair Blown Pro Street cruiser 1971 Camaro Pro Touring 1973 Vega Drag Car 1970 C20 tow rig

10-15-2011, 03:37 PM	#24
denny5625 Registered User Join Date: Jul 2007 Location: Kennewick, WA Posts: 152	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! Posted via Mobile Device Posted via Mobile Device __________________ 66 el Camino 70 1/2 RS Z-28 71 C10 2wd 72 2 wd Blazer (2) 72 4 x 4 Blazers 88 24' Mirage 70 mph+ 08 Harley Night Train 08 Silverado 4d 4 x 4

10-15-2011, 04:45 PM	#25
Daves70 Registered User Join Date: Jul 2011 Location: Mt Brydges Ontario Posts: 181	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.

Register or Log In To remove these advertisements.