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400 cid SBC

9K views 20 replies 11 participants last post by  dirtracer21inc 
#1 ·
I've got some questions about the 400 small block chevy. My brother in law just scored a 1970 Monte Carlo w/ a 400/ auto. The problem is that the guy he's getting it from bought it for the engine and tranny, so we need to find another one to put in there when we get the car. It's a 1970 Turbo Fire 400, and the main question is what other 400 's will work? I know they only put them in Montes in 1970, but what about truck blocks? They used a 400 sbc for pickups all the way to 78, but is it the turbo fire 400? What's the difference between a turbo fire and non turbo fire engine? I'm clueless in the chevy game, always loved the monte carlos, but only owned buicks and fords.
If anyone can tell me where to look for some info, I'd really appreciate it.

Brado :confused:
 
#3 ·
Turbo Fire was just a name, that is what they called the small blocks. Just like the big blocks used to be called Turbo Jets. The nice thing about a Chevy small block is that they're all pretty much the same. The 400s in the pickups are the same as the 400 that was in your Monte. Just like 56 said, any small block that has provisions for engine mounts on the side of the block will work, which all 400s have. Or even a 350 if you so choose.
 
#4 ·
:thumbup: Cool, that's good to know. I'm planning on yanking a 400 out of a truck boneyard, and wasn't sure what would work. I've decided to go w/ the 400 because the 350 route has been overplayed in my little circle of friends,and all the performance sbc stuff will fit ( won't it??). I'm thinking this car is going to be a lot of fun...
 
#6 ·
Well, I'm not planning on doing a lot of performance stuff to it at first. The boneyard I'm getting the 400 from sells running engines (you get to hear it run before they pull it out of the vehicle) I'm just going to drop it in and drive it for a little while. Later on, when I have more money, it'll be getting a rebuild and some good heads, intake, upgraded carb, all the bolt on stuff. This is the best plan I've come up with on my budget (which is about $1500 for car, engine and tranny, suspension and brake rebuild). Does anyone else know any other better budget approach then getting a running engine out of a boneyard?

Brado
 
#7 ·
Sbc 400

Hi Shades of Gray -

Strokr40 here, just an FYI SBC 400's aren't the bee's knees! They have an inherent weakness - thin cylinder walls - overheat them twice and they're junk - cylinder walls thin at the webbing - prone to cracking. I would take a 350 CI from say a pick up - 4 bolt main, punch it .30 over with a mild build good steel crank, forged rods - pistons, good breathing steel heads, properly matched to the intake & carb with a free flowing exhaust and you'll be eating 400 c.i.'s for lunch!!! In the end - the motor will wind more, have a longer power band (depending on carb, cam intake head combo's) you'll have a motor with tons of torque & power - more potential as compared to the 400 c.i. Lots of guys build 400's for drag motors - short lives with planned overhauls - not the type of application you'd be planning on. If you really want to go crackers build it with NOS tolerant equipment and you'll be bangin on the far side of the 500hp neighborhood! That should scare the natives when they pull along side a mild looking or sleeper Monte, eh? Just bear in mind that Turbo 400 wil have no OD so you'll be sacrificing the true top end potential of a motor like this, unless u use another option as you'll be in the market for a tranny anywho get a 700R4 and beef it up w/a good kit and reasonable torque converter - that would be 1 sweet set up then.
Strokr40
 
#8 ·
Umm Strokr...do the same things to a 400 that you are suggesting be done to a 350 and that 400 will kick the pants off the 350. No comparison. People build high powered 400s all the time, and not all of them see life as drag engines either. Just ask one of the many 400 owners in here.

Shades, if you've got a 400 build it. You wont be disappointed.
 
#9 ·
Well, it looks like it may end up being a 350 for now. I just got word from a friend up at the junkyard that he's holding a 79 Caprice w/ a 350, th 350, posi rear for me, and I can have the whole drive line (running !!!) for $400. That's about what my budget will allow, so the 400 will have to be a later project. This is just going to be a driver for about a year or so anyways. Then I can go nuts and build something crazy. :evil: But I have so many more pieces to find before I can even get this thing on the road :(
 
#10 ·
If you are trying to watch your money Shades-o-Grey then the 350 might be the best choice in the long run,rebuild kits are cheaper for the 350 for one,I have two 400's, one is still in use around the house only, I took it off the road when gas so high, they love the gas compared to a 350, you wouldn't think that an 1/8th of an inch in bore would make much difference but it does, I have the one in a 76 Elcamino and 8 to 10mpg is about all it will get, when I had the 350 in it I would get 15 to 18mpg,big differance in the power however between the two ;)
 
#11 ·
Man I would put another 400 in it if it was me. On the street you can't beat the torque they put out and with a little modifications they will run cool. We add a t-fitting to the top of a Stewart stage lll water pump and run it to the drain plug on the side of the block between the two middle cylinders. Also run a double pass aluminum radiator and a couple of lines off of the thermostat housing back to the back water jacket on the intake manifold and this motor will never run hot. Light weight and torque all in one package. :thumbup:
 
#12 ·
Shades_o_Grey said:
I've got some questions about the 400 small block chevy. My brother in law just scored a 1970 Monte Carlo w/ a 400/ auto. The problem is that the guy he's getting it from bought it for the engine and tranny, so we need to find another one to put in there when we get the car. It's a 1970 Turbo Fire 400, and the main question is what other 400 's will work? I know they only put them in Montes in 1970, but what about truck blocks? They used a 400 sbc for pickups all the way to 78, but is it the turbo fire 400? What's the difference between a turbo fire and non turbo fire engine? I'm clueless in the chevy game, always loved the monte carlos, but only owned buicks and fords.
If anyone can tell me where to look for some info, I'd really appreciate it.

Brado :confused:
if u can get a later model truck block sbc 400 they are better to have machined from what i hear
 
#13 ·
strokr40 said:
Hi Shades of Gray -

Strokr40 here, just an FYI SBC 400's aren't the bee's knees! They have an inherent weakness - thin cylinder walls - overheat them twice and they're junk - cylinder walls thin at the webbing - prone to cracking. I would take a 350 CI from say a pick up - 4 bolt main, punch it .30 over with a mild build good steel crank, forged rods - pistons, good breathing steel heads, properly matched to the intake & carb with a free flowing exhaust and you'll be eating 400 c.i.'s for lunch!!! In the end - the motor will wind more, have a longer power band (depending on carb, cam intake head combo's) you'll have a motor with tons of torque & power - more potential as compared to the 400 c.i. Lots of guys build 400's for drag motors - short lives with planned overhauls - not the type of application you'd be planning on. If you really want to go crackers build it with NOS tolerant equipment and you'll be bangin on the far side of the 500hp neighborhood! That should scare the natives when they pull along side a mild looking or sleeper Monte, eh? Just bear in mind that Turbo 400 wil have no OD so you'll be sacrificing the true top end potential of a motor like this, unless u use another option as you'll be in the market for a tranny anywho get a 700R4 and beef it up w/a good kit and reasonable torque converter - that would be 1 sweet set up then.
Strokr40
pluging the deck with water restrictors and studding the deck also, that will strengthen the cylinder walls
 
#14 ·
dirtracer21inc said:
Man I would put another 400 in it if it was me. On the street you can't beat the torque they put out and with a little modifications they will run cool. We add a t-fitting to the top of a Stewart stage lll water pump and run it to the drain plug on the side of the block between the two middle cylinders. Also run a double pass aluminum radiator and a couple of lines off of the thermostat housing back to the back water jacket on the intake manifold and this motor will never run hot. Light weight and torque all in one package. :thumbup:
thats interesting wonder if running them to each cylinder head would work well also?
 
#15 ·
A quick note to the orginal pole poster here they put 400's in other cars than montes in 70 including impla's etc and as for any one wanting a 350 over a 400 is smoking crack sure you can make a 383 run or even a 350 but all the problems spoken of here is mostly caused by pore machine work etc 400 is the way to go dosent take hardly anything to make a 450 plus hp sb 400 or even a 406 im building a 421 out of my 70 400 block with 6" rods 3.875 crank etc so no worries just make sure any after market heads are drilled and enjoy the power
 
#17 ·
Shades_o_Grey said:
I've got some questions about the 400 small block chevy. My brother in law just scored a 1970 Monte Carlo w/ a 400/ auto. The problem is that the guy he's getting it from bought it for the engine and tranny, so we need to find another one to put in there when we get the car. It's a 1970 Turbo Fire 400, and the main question is what other 400 's will work? I know they only put them in Montes in 1970, but what about truck blocks? They used a 400 sbc for pickups all the way to 78, but is it the turbo fire 400? What's the difference between a turbo fire and non turbo fire engine? I'm clueless in the chevy game, always loved the monte carlos, but only owned buicks and fords.
If anyone can tell me where to look for some info, I'd really appreciate it.

Brado :confused:
I do beleive that the 70 impala had it as well, because my buddy bought a 70 vert and she had the 400 badges as well
 
#18 ·
the only difference in 400's from 1970-1980 is that there are 2 and 4 bolt main block's.509,511 and 817.509 two bolt is the block to have.big webbing in the the main area and you can do the conversion to four bolt at home with a kit.the 509 is about 12 lbs.lighter and is better detailed in looking at them side by side.they aer all very capable motors and you are lucky to have one if it is in good shape after leaving the machine shop.good luck.check the info at mortec.com
 
#19 ·
re: 400 SB

Hi Gone Nova/

I'd say this is probably one of the best post threads on this site - the 350 camp chimed in and the 400 camp has certainly fielded some great points - me I've built a killer 383 from a 350 4 bolt main, Eagle rotating assembly all good stuff and enjoy the heck out of it. In the end I appreciate all the feedback - even those that felt I maybe smoking "big white rocks" for preferring a 350 vs a 400 c.i. I would say in the long haul the 400 crew has put that block back on my radar screen w/a more favor opinion - who knows maybe the next SB bowtie will be a 400 - gasp did I say that! - LOL

thanks to all who have opted in

strokr40
 
#20 ·
Reply to thread

For those not familiar with the SB 400 - remember that it is an externally balanced engine. If you use the flex plate from a 350, or don't index the flexplate from the 400 correctly, you will have major vibration problems.
I had a SB400 in my '79 Malibu. I built a beefed-up THM350 for it and loved the performance (added Edelbrock cam and manifold). It is a strong torquer but should not be revved real high unless engine is built for the purpose. The short connecting rods mean high rod angles and higher internal stresses.
 
#21 · (Edited)
For those that would like to internally balance, Scat, Eagle, Calles dragon slayer, etc make cast steel and forged steel cranks that will easily fit the bill. Cast steel start at $230 and up, with forged as cheap as $450 and up. I recently rebuilt a 400 using the stock crank with only a .010 clean up and new balancer/ flex plate. The price of the whole thing ( machine shop bill,pistons gaskets, etc. came to $1475. I didn't think that was too bad and it runs great even at 6500+ rpm for short bursts on an external balance. I would not do this for an all out race motor but for the street I sure got my money's worth. I came across some used swap meet bowtie heads and $500 bucks later (counting the purchase price) they were as good as new. Man talk about cheap horsepower. If I could not find a good 400 block I would build a 383 only use internal balance parts and have almost as much horsepower. Also with the 383 you won't have as much trouble keeping it cool. I plumbed into the water pump and ran lines to the drain plug just above the middle cylinders. Also run cooling lines from the thermostat housing to the back water jackets on the intake manifold even if you have to drill and tap your own holes. These two things dropped my temp 20 degrees. I don't have any cooling problems at all now. But........I already had the 400 and new the history of it or I probable would have done a 383. Now for those that the sky is the limit Dart makes some nice blocks etc..............I almost forgot.....I used 5.7 350 (X) rods and speedpro forged pistons. You only need to grind a little on the top of the rod bolts for extra clearance.
 
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