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

mikegi · 05-19-2003, 06:52 PM

have a chance to buy a 400 small block out of a 72 caprice.the question is how do i tell if it is a 400 ( besides the #s on block)do 400s have 3 freez plugs? and the guy said it has a 2 barrel on it.must travel about 100 miles to get it ,just don't want to get there and find out it's a 307 (not that i have done that) lol.

Eddie H. · 05-19-2003, 07:13 PM

You can identify a sb 400 by the harmonic balancer with a counterweight on it. They were externally balanced, all other small blocks were internally balanced. All of them I've seen also have 3 freeze plugs on each side. If I remember correctly, they only came in 2 barrel versions.

Blue_71 · 05-19-2003, 07:36 PM

mine has 2 on each side and 2 on the front, and i have ran the numbers, its a 76 400

neonlarry · 05-19-2003, 07:42 PM

I was just going to say the harmonic balancer but someone slipped in before me with that. That and the suffix code are the best, on a Caprice you should be able to see the # fairly easy.
When you get there though unless its really really cheap I'd pull the heads and check for cracks between the bores and also check the pistons to see if they are oversize and how much, .060 over is about the limit on a 400 unless you want to sleeve it. Good Luck I'm still looking for a good 400 block myself.

mikej71 · 05-19-2003, 08:06 PM

I believe that a 2 bolt 400 has 2 fleeze plugs on the side, and a 4 bolt has 3. I may have that backwards, and I'm too lazy to go out and look at mine. Anyhow, 400s have both 2 and 3, so that's not a good test. Definitely try to see the casting #s.

Mike

Longhorn Man · 05-19-2003, 08:27 PM

Hope for a 2 bolt...the 4 bolt ones were not as strong.
Not all had the extra freeze plugs, many had the bosses for the plugs, but some had no plug, no boss. (like the one I sold Blue)

Blue_71 · 05-19-2003, 08:45 PM

hmmm.. ya know horn, that makes it really easy to claim it as a smaller engine if i wanted to trick someone after a race

dinnut · 05-19-2003, 09:29 PM

i noticed the strength factors in my white and blue truck. the white truck engine is a 350 out of a 72 chevelle. even though its a 2 barrell it is a lot louder overall. a lot of difference in a truck and car engine. blue truck has a truck 350. runs a lot different. i can light em up off the line easily on that 2 barrell 350 ( its got a cam bc it lopes - hehe) blue truck engine is alot better running even though the passing gear isnt hooked up.

Low69CST · 05-19-2003, 10:03 PM

4 bolts have 3 freeze plugs and 2 bolts have 2 freeze plugs. I built a 4 bolt block. I had a 2 bolt block but didn't have the cash for splayed caps. So I stuck with the 4 bolt, I'm not drag racing, so my ocasional heavy foot shouldn't hurt it. I can't remember any other external clues to whether its a 400 or not, Balancer size is only way i know. You could tell the guy to yank off the heads and measure the bore, stock is 4.125. It would be a good idea to check the cylinder walls anyway, if it would have to be bored bigger than .030 I would stay away from it.

Longhorn Man · 05-19-2003, 10:49 PM

Another thing comes to mind, on the sides of the block, where the freeze plugs are, the 400 bulges around each cylinder.
The 2 bolt = 2 freeze plugs and 4 bolt = 3 plugs does not always hold water. I have owned a 400 that was a 4 bolt that had 2 freeze plugs. It was the one that was in my GMC when i bought it.

chevy69er · 05-20-2003, 01:21 AM

If your gonna have the heads pulled off check for steam holes on the deck of the block.They are between the cylinders.

Blazer1970 · 05-20-2003, 08:05 AM

A 400 SB with a 2bbl in a '72 Caprice should have suffix code CKP. If it was a police or taxi application, it could be CDL or CDM. A 4bbl could be CTB.

mikegi · 05-24-2003, 06:51 AM

going on road trip this morning,thanks for the info.motor has 3 freeze plugs and counter weight on balancer.the guy said it ran excellent and did'nt burn oil.we'll see,can't wait.i'll let you all know how i made out.by the way its got a th 350 tranny,will that hook right up to our trucks??

dinnut · 05-24-2003, 03:29 PM

mostly all auto 350s had th350s behind them.

mikegi · 05-24-2003, 04:40 PM

well igot there and it was a 4 bolt 3 freeze plugs,but high miles and noisy.some people think they have something worth of value when they really don't.the motor was really worn.Oh well,thanks for all your input

Tracy Focht · 05-24-2003, 06:43 PM

Quote:

Originally posted by mikegi
well igot there and it was a 4 bolt 3 freeze plugs,but high miles and noisy.some people think they have something worth of value when they really don't.the motor was really worn.Oh well,thanks for all your input

so did you get it?

mikegi · 05-24-2003, 06:53 PM

i passed on it

Longhorn Man · 05-24-2003, 11:44 PM

You could get it pretty cheap since it sounds sick, and give it a second life with rings and bearings.

05-19-2003, 06:52 PM	#1
mikegi Registered User Join Date: Jun 2000 Location: Springvale,Maine Posts: 201	? on 400 small block have a chance to buy a 400 small block out of a 72 caprice.the question is how do i tell if it is a 400 ( besides the #s on block)do 400s have 3 freez plugs? and the guy said it has a 2 barrel on it.must travel about 100 miles to get it ,just don't want to get there and find out it's a 307 (not that i have done that) lol. __________________ Springvale,Maine 71 3/4 GMC lwb

05-19-2003, 07:13 PM	#2
Eddie H. Registered User Join Date: Mar 2001 Location: Paradise TX USA Posts: 1,200	You can identify a sb 400 by the harmonic balancer with a counterweight on it. They were externally balanced, all other small blocks were internally balanced. All of them I've seen also have 3 freeze plugs on each side. If I remember correctly, they only came in 2 barrel versions. __________________ "Negative people always seem to have a problem for every solution"

05-19-2003, 07:42 PM	#4
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,745	I was just going to say the harmonic balancer but someone slipped in before me with that. That and the suffix code are the best, on a Caprice you should be able to see the # fairly easy. When you get there though unless its really really cheap I'd pull the heads and check for cracks between the bores and also check the pistons to see if they are oversize and how much, .060 over is about the limit on a 400 unless you want to sleeve it. Good Luck I'm still looking for a good 400 block myself. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

05-19-2003, 08:06 PM	#5
mikej71 Unregistered User Join Date: Dec 2001 Location: Houston, TX USA Posts: 538	I believe that a 2 bolt 400 has 2 fleeze plugs on the side, and a 4 bolt has 3. I may have that backwards, and I'm too lazy to go out and look at mine. Anyhow, 400s have both 2 and 3, so that's not a good test. Definitely try to see the casting #s. Mike __________________ 71 SWB Stepside SB400/TH350

05-19-2003, 09:29 PM	#8
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	i noticed the strength factors in my white and blue truck. the white truck engine is a 350 out of a 72 chevelle. even though its a 2 barrell it is a lot louder overall. a lot of difference in a truck and car engine. blue truck has a truck 350. runs a lot different. i can light em up off the line easily on that 2 barrell 350 ( its got a cam bc it lopes - hehe) blue truck engine is alot better running even though the passing gear isnt hooked up. __________________ 70 longbed 496/th400/Ford 9"

05-19-2003, 08:27 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Hope for a 2 bolt...the 4 bolt ones were not as strong. Not all had the extra freeze plugs, many had the bosses for the plugs, but some had no plug, no boss. (like the one I sold Blue)

05-19-2003, 08:45 PM	#7
Blue_71 Bloo Join Date: Feb 2001 Location: Barren County Kentucky Posts: 6,283	hmmm.. ya know horn, that makes it really easy to claim it as a smaller engine if i wanted to trick someone after a race

05-19-2003, 10:03 PM	#9
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	4 bolts have 3 freeze plugs and 2 bolts have 2 freeze plugs. I built a 4 bolt block. I had a 2 bolt block but didn't have the cash for splayed caps. So I stuck with the 4 bolt, I'm not drag racing, so my ocasional heavy foot shouldn't hurt it. I can't remember any other external clues to whether its a 400 or not, Balancer size is only way i know. You could tell the guy to yank off the heads and measure the bore, stock is 4.125. It would be a good idea to check the cylinder walls anyway, if it would have to be bored bigger than .030 I would stay away from it. __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

05-19-2003, 10:49 PM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Another thing comes to mind, on the sides of the block, where the freeze plugs are, the 400 bulges around each cylinder. The 2 bolt = 2 freeze plugs and 4 bolt = 3 plugs does not always hold water. I have owned a 400 that was a 4 bolt that had 2 freeze plugs. It was the one that was in my GMC when i bought it.

05-20-2003, 01:21 AM	#11
chevy69er Registered User Join Date: Feb 2003 Location: Lakewood,Ca Posts: 69	If your gonna have the heads pulled off check for steam holes on the deck of the block.They are between the cylinders. __________________ 1969 C-20,383 stroker,sm465,custom long travel front suspension,4 wheel disc brakes,35" pro comps...mods under way include: 4x4 conversion,and custom bumpers.future mods include: gear vendors od unit,and relocation of fuel cell.

05-20-2003, 08:05 AM	#12
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,507	A 400 SB with a 2bbl in a '72 Caprice should have suffix code CKP. If it was a police or taxi application, it could be CDL or CDM. A 4bbl could be CTB. __________________ Tim

05-24-2003, 06:51 AM	#13
mikegi Registered User Join Date: Jun 2000 Location: Springvale,Maine Posts: 201	going on road trip this morning,thanks for the info.motor has 3 freeze plugs and counter weight on balancer.the guy said it ran excellent and did'nt burn oil.we'll see,can't wait.i'll let you all know how i made out.by the way its got a th 350 tranny,will that hook right up to our trucks?? __________________ Springvale,Maine 71 3/4 GMC lwb

05-24-2003, 03:29 PM	#14
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	mostly all auto 350s had th350s behind them. __________________ 70 longbed 496/th400/Ford 9"

05-24-2003, 04:40 PM	#15
mikegi Registered User Join Date: Jun 2000 Location: Springvale,Maine Posts: 201	well igot there and it was a 4 bolt 3 freeze plugs,but high miles and noisy.some people think they have something worth of value when they really don't.the motor was really worn.Oh well,thanks for all your input __________________ Springvale,Maine 71 3/4 GMC lwb

05-24-2003, 06:53 PM	#17
mikegi Registered User Join Date: Jun 2000 Location: Springvale,Maine Posts: 201	i passed on it __________________ Springvale,Maine 71 3/4 GMC lwb



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05-24-2003, 11:44 PM	#18
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	You could get it pretty cheap since it sounds sick, and give it a second life with rings and bearings.

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