My .02 on the cooling.

I ran a 400 in a '65 Chevy II for a couple years. I used the narrow, Harrison single core(19"?) radiator. Clutch fan with no shroud. It should have had one. Automatic transmission with cooler in the radiator. In other words, I used what I had handy. It was admittedly the bare minimum. It worked fine except for one time. I got caught in one of Gatlinburg Tn.'s famous traffic jams. All the way from Pigeon Forge to the mountains on the other end of town. 90+ degrees that day. After about an hour of that, it got hot. I took a back road and got moving and it immediately cooled down. That's the only time it ever tried to get hot. Later I put a 350 in the car and gave it to my kid to drive. I never got hot with the 350 but it never went back to Gatlinburg again, either.

I don't see where there's any particular problem with keeping one cool. I think if you look at the radiators/shrouds they used on the factory equipped 400's, you won't find much, if any extra capacity over the 350.

 

VETROD, that looks like a pretty wild green 61......those look like early Camaro tail lights.......I've never have seen that application before.

Looks like the 377 does the job.

 

I also have been running a mild sb400 in my '65 for the last several years. The bad rap these engine have about overheating is because of the use of crappy castings for the cyl heads. I had my friend at one of the big engine shops select some better castings from his cores to build for me. FYI, many of the sb400 don't have the holes drilled for the clutch z bar ball. Better to notice that when the engine is on the stand The bosses are there to drill and tap.

 

Nope they are not camaro lights. There are others around with the same lights. Yes that 377 works very well and runs 11.70s

 

Please stop perpetuating this myth. The reason this started is in the 70s everyone put 350/327 heads on the 400s with out drilling the steam holes, traped air in the block, hence they over heated.

I have a 415, 10:1, Cast Iron heads, Solid Roller cam in a 55 Belair. If you know Cars you know Tri 5s have no air under the hood and are known to run hot.

Last Summer I was on Woodward Ave I went 5 miles in 3 hours 90* heat and my car was never over 195*. Only the coolest cars can pull that off.

 

The story continues:
Went again last night to take compression and hear the 400 run.

Seller had a rebuilt starter, so we first did a compression check and I have some concerns with that. 7 cylinders were at 130 psi and one had 120. The engine has been sitting in his garage for 2 years and he did not put oil down the cylinders before storing (his bad).

Does anyone know what compression should be on this engine? Pistons are stock style and the head has 487 castring numbers and 75 CC combustion chambers. It should be low compression but 130psi???? I wonder if there may be some rust on the valves and seats from sitting for 2 years with no oil on them which could affect the compression. Or are the rungs sticking?

Maybe we should put some marvel mystery oil in the cylinders then run the starter on 24 volts to spin it fast???? I know of a case where that was a solution to start a long sitting smallblock with stuck rings.

The motor seemed to be out of time and did not start. The seller had earlier replaced the gear drive with a timing chain setup in preparation to sell the engine and he thinks that he had the timing marks aligned, but was unsure.

He thought the distributor was 180 degrees off and reset it but it still did not run. It sounded close to starting while twisting the distributor, but no go. At times there was fire coming out the carb and exhaust at the same time. Spark is good.

It got late and everyone was tired, his battery was dead so we quit for the day.

In hindsight it probably didn't do the cylinders any good to be cranking so much without having squirted oil down them. It was turning over fairly fast so maybe there was enough oil splash off the crank for some cylinder lubrication....don't know though.

The kid who had run the engine in the 79 Malibu showed up and vouched for the engine. But he also thinks it was bored .060 over and that concerns me. He did say it ran cool, about 190 except once in city traffic when it got up to 220, but cooled down OK when out on the road.

I called the machine shop that did the work and while helpful they didn't know if the heads steam holes were drilled and I don't know if they had the overbore info. The seller thinks he has shop receipts for machine work but hasn't found it yet.

Seller's Dad , who's a mechanic is planning to visit him today so maybe he can help.

Sure wish I could see the machine shop documentaion of bore size and head work.

Oh well, I'll see what happens. There's lots of smallblocks out there for sale all the time, and I don't need an engine yet anyway.

 

100%

As I mentioned earlier, when extra attention is given to the block at a competant machine shop and properly built with steam holes in the heads, the SB400 can be built into a brute of an engine. And the great part is that it just slides right into ANY PLACE where a small block fits with ZERO modifications. For example, a SB 400 is a pure drop-in for a 55 Chevy, 67 Camaro, a 72 Chevelle with a tired 307 2bl carb or any Corvette. Make sure the receiving vehicle has an adequate cooling system, and you have an incredible package---------------without cooling issues!
If you desire to use iron exhaust manifolds, ANY Chevy that will accept the conventional Ram Horn exhaust manifolds (Ram Horns won't work on Camaros-Chevelles-Novas) should have 2 1/2in manifolds installed. In my opinion, the normal 2in manifolds are not adequate for a healthy SB400. Otherwise, headers should be used on a SB400. ALLLLLLLLLLLLLLLLLLLLLLLLL BB 396-402 engines have 2 1/2in iron ex manifolds and they are 400 cubic inch engines-------------------so why not use an exhaust manifold or header on a SB400 which has the same displacement!

 

DZAUTO, can you give me an ballpark figure for what compression reading this motor should have with stock type pistons and 75cc 487 350 heads? Thanks.

A successful run of the 400 ci smallblock:

The seller called me back yesterday to come hear the 400 run. I did and it sounds good.

His Dad stopped by and noticed that only the #1 cylinder was firing correctly.....all other plug wires were off as his son pictured the rotation of the ignition rotor backwards....doh! Too many adult beverages after a long days work, and he is a body man by trade, not a pro engine builder.

The seller found a few receipts from the time of building the engine and discovered it was May 03, not May 05, so it has been sitting about 4 years, not 2 years.

We agreed on a price of $750, including an engine stand and extra head with new valves. The engine has a new 750 Edelbrock carb, Edelbrock Performer intake, chrome valve covers and oil pan. New water pump and HEI, plugs, and plug wires. Has an alternator mounted. Engine is detailed with some parts powder coated and everything else painted.

I bought this as a drop in engine for when I get to that point.....feels like a major milestone along the way.

Thanks again to all responders about 400 smallblock details.

 

Funny about the reverse order plug wiring, I went to look at a 71 coupe with a friend. They had done a tune up & it wouldn't start, I noticed that the wire after #1 went to #2 & the one before to #8, Ford style! I told my buddy, he got the car for half of asking price.

 

My stock bore, no ridge, re-ring engine has 148-154 lbs. I don't know the head casting #'s but they're nothing fancy. Mild rv cam.

 

Thanks 00FXD for the compression details. After the engine was run a bit the one cylinder that was low came up to the same 130 psi as the other seven. Maybe I didn't have the tester screwed in securely on the earlier test.The low compression is a concern. I hope there is not permenant damage from the seller not preping the engine for storage correctly.

I plan to shoot some Marvel Mystery oil down each plug hole , spin it over and let her sit (with an occasional rotation or two) until the car is ready. I may even start it periodically since it's going to be some time before the car is ready.

Thanks for the heads up on the Z Bar bracket mounting holes. The block has two threaded bolt holes near the rear of the block on the drivers side. Since it's a 4 bolt main engine my guess is it was in a pickup or something with a stick. I think the C-1s Z Bar engine side bracket was designed to mount on the bell housing, unlike C-2s and C-3s which mount on the stud ball which screws into the block.

 

I have not owned a c1 but I do belive that the clutch ball stud mounts on the bell housing. I just added that the sb400 blocks are not all drilled and tapped for the clutch ball to prevent any nasty supprises for others

 

had to fabricate new z-bar bracket when i changed bell housings:

old



new



Bill

 

It is true that the 55-62 Vettes with a manual tranny (that's right, there WERE a few 55s with a 3sp) had the ball stud for the Z-bar attached to a metal plate which bolted to the side of the bell housing with 2 bolts.

MOST, SB400 blocks have the boss for the ball stud drilled and tapped. But, if the boss is not drilled/tapped, it is just tooooooooooooooo easy to do it-------------------unless, of course its already in the car.

Vehicle application had ABSOLUTELY ZERO affect as to whether or not a SB400 was 2bolt or 4bolt.
ALLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL 70-72 model SB400 blocks, no exception, were 4bolt. Then, beginning with the 73 models, ALLLLLLLLLLLLLLLLLLLLLLLLLL SB400 blocks were 2 bolt, no exceptions.
It is possible (but I have not personally observed it) that some VERY, VERY early 73 cars recieved left over 72 4bolt engines,but that would have been an extreme exception.
Also, some 2bolt and 4bolt 400 blocks have the same casting number, just as some 350 engines with 2bolt and 4bolt blocks have the same casting number, particularly the 010 blocks.
Beginning with the 70 SB400s, they all had 2bl carbs and in 75, some got a Q-jet.
Not all 400s had 3 freeze plugs.
Beginning in 70, 400s had 3 freeze plugs, then about 75, the blocks were cast with the middle boss for a freeze plug but no freeze plug was installed. The latest 400 blocks didn't even have the middle boss. Thus, examining a block for 3 freeze plugs is not necessarily a sure fire way to identify a 400, BUUUUUUUUUUUUUUUT, if it does have 3 plugs, then for sure it is a 400!

 

I had a 1970 Monte Carlo with a sb400/330hp, 4bbl q-jet & a turbo 400. This was the original engine, & even with the stock hydraulic cam, it ran with the 396 Chevelle's.

 

DZAUTO, thanks for the clarification about which 400s are 2 bolt and which ones are 4 bolt. My 400 has a May 28, 72 casting date indicating that it's a 4 bolt.

BTW, do you know what heads came on 400s from the factory?

Thanks, Doug

 

Actuall, I have found the 72 (late) blocks- 3951511 -too have 2 bolt mains.

 

BUUUUUUUUUUUUUUUUT, was it installed in a LATE production 72 model, or, did it have a late 72 casting date for a very early production 73 model car? Regardless, the break between 4bolt and 2 bolt blocks was 72-73. It is certainly possible that some VERY late 72s got a 2bolt block.

 

Not that it proves or means anything, but every 400 I've taken apart had 882 heads on them.