Ford 400
Bore 4.00
Stroke 4.00
Bore/Stroke ratio 100%
Rod Angle 17.7*
Riciprocating weight: 1000g
Piston speed at 6000rpm-3980fps
Canted Valve cumbustion Chamber

Chevy 400
Bore 4.125
Stroke 3.75
B/S ratio 91%
Rod angle 20*
Riciprocating weight 1068g
piston speed at 6000rpm-3750fps
inline wedge combustion chamber

Mopar 400
Bore 4.34
Stroke 3.38
B/S ratio 78%
Rod angle 15.4*
Riciprocating weights 1344g
Piston Speed at 6000 rpm 3380fps
wedge combustion chamber

Lot's of people have Ford 400's in their vintage Ford trucks and love them. After all it's basically a 351C 2bl stroker in a raised block(to maintain good rod ratios). I had one and it ran forever, got 14mpg pulling a 30 ft gooseneck, and always had plenty of power on tap.

One of my boss's had a Chevy 400 in one of his trucks and it was absolutely the worst perfoming American V8 I have ever enccountered. Just gutless. It Blew up at 60,000 miles. Drank gas like crazy. It should of had the most low end with it's short rods, but it didn't. Had an overheating problem too. This Chevy taught me a lot about Bow- Tie engineering excellance.

Had an uncle with a 400 Mopar once too. Not much grunt down low in comparison. This shouldn't be surprizing since it had the least stroke and the longest rods. It revved like a diesel, but it was extemely tough. It drank gas like you would expect a big block to.

 

Believe it or not, those canted valve wedge heads became a terrible hinderance once the chambers had to be opened up to lower compression for lower octane and the smog laws.

As much as I hate to admit it, the fact that GM stuck it out with one basic design instead of 3 contibuted to their success.

BTW, long rods are more adventagous to torque.........more mechanical leverage.

One negative to the 400 SBC was the siamesed cylinders, no water jacket between cylinders, this caused cooling problems on some but not all 400 SBC's.

 

Short rods should give you a fatter tourqe spike in the lower rpm ranges because they cause the piston to travell faster away from TDC. This greatly increases the drawing power (both volume and velocity) of the intake charge into the cylinder. Short rods give better volumetric effiency at lower rpms. long rods cause the piston to quickly move toward TDC and therefore build dynamic compression as rPM's increase. Short rod motors loose dynamic compression as RPM's increase. On the other hand you get a longer dwell time at TDC with longer rods and the fact that the rod angle isn't trying to push the piston into the water jacket may help the long rod engine in the low end.

The open chamber canted valve heads on my 400 didn't seem to hurt things much. The inline heads on the chev 400 certainly made much, much, much less power from the same cubic inches.

 

The long stroke on the Ford 400 produced great torque or "low end grunt". It was a great engine for heavy vehicles. The first year production (1971) engines were amazing but compression was lowered the second year etc etc and killed off a great engine.

 

P51D, My experience has been the polar opposite of yours. I had a 400 in my 78 lincoln mark 5, and it was a complete boat anchor. It had some low end grunt, but that is ALL it had! I think those 400's were only rated at something like 160 hp. Maybe 180? That is not "plenty of power on tap" in my book. It did run great, however. No matter how cold it was, subzero temps did nothing to it. I would turn the key and it fired immediately. My best friend had a chevy malibu with a 350 (still has it) a 1976 model. That 350 malibu would school my lincoln every time.The 350 finnaly puked. We just finished putting a 400 sbc in it last week. The 400 chev we put in there was out of a 76 pickup. It has a lot of snap. Much better than the 350. And worlds better than a 400 ford. But, I have had people on this forum tell me before that the 400 was not a bad engine at all, and that I must have had problems with mine. I know I did not have a single problem with mine, it's just a low-output engine. And as torque1st said, it had the potential to be a much better engine. IMO, of course.------Ryan

 

All I remember out of the mists of time is that we'd wholesale any Ford or Chevy 400 with over 75K miles on it back in those days- no questions asked. I do recall, somehow, the Ford 400 wasn't a real powerhouse (sure sucked gas though) and the Chev 400 had some durability issues.

 

I dont know what brainiac at Ford thought up the open chamber non-quench heads, but it wasn't the best idea in the world. Just try to raise the compression ratio without pinging!

The chevy had siamesed cylinder walls. Disaster waiting to happen IMO. If you could keep it cooled off, it'd probably do alright.

The Mopar 400 should rev up good, with it's big bore and short stroke. It would be at home in a muscle car, not a truck.

 

The pass car Ford 400's not only had more pollution control garbage but a different(rather wimpy) cam than the truck motors. Moreover, the cam on both truck and car was 4* retarded. This problem was compounded by the use of nylon gear timing gears that quickly wore and caused the cam to run even further behind. This was what the problem was with poor running 400's. The trick that was pretty common was to install the 351C Marine cam straight up. This restored the engine close to it's 71 performance level.

The Mopar 400 doesn't rev good because it's reciprocating componants weigh too much. This is the main problem with most vintage Mopar V8's.

Armourer, We will knock on wood and keep our fingers crossed that your friends 400 SBC works out okay.

 

But what was the 400's performance level in 1971? Still nothing to write home about. I think the 390FE was a much more capable engine. Heck, you could get about the same power as a late 70's 400 with the 300 I6. Better mileage, too. The only thing the 400 has going for it over the six cylinder is sound. You can put glasspacks behind that engine and sound like you're driving a truck as opposed to a hay baler.

 

Your increased dwell at TDC(as long as the cam is matched to fill the cylinder) is the MAIN reason the longer rod is advantageous. That and the leverage.....the negatives are pin placement and piston crown heighth. (again, longer rods are a common SBC mod when rebuilding)


There are 2 tricks when building 302's, both increase torque and HP across the board;


The long rod/piston swap (5.4" rod???) is good for 20+ HP/Torque....I never quite understood that one though. If you're that deep into the motor(parts wise) you might as well pop for a stroker crank too.

The next one I've used and learned fron Joe Sherman (very well known ch*vy builder) The stock replacement 302 pistons have an offset piston pin to increase side load (basically shortening up the rod a few thousanths) so as to negate any piston slap when cold.

By simply putting in the Piston backwards (make sure to check p/v clearance) you are in effect increasing the rod length at TDC if only by the same few thousanths. This has shown an increase of about 10 HP/torque for 0$$$. The negatives are the possibility of some piston slap when cold. I've run TRW forged slugs at .003 and have not heard any rattling.


With all due respect, you are the first person I've heard claim the 400 was a powerhouse in its stock configuration.....truck or not.

 

I had the 400 in my 79 Lincoln back in the day. It was no power house by any means but as I remember correctly, it was buckled up to a 2.73 rear gear set. That's a lot to ask of any engine in that size car.

Not to show too much ignorance but did both of the GM 400s have the same measurements? I think the large block was totally different from the small block. My uncle had a large block in a 1/2 ton. Run really good for the first 150,000 miles and then he sold it. He really liked that truck.

 

LOL!!! Totally had me confused when I first saw it also............GM was too cheap to change the fender numbers so the 402 BBC had 400 badges!!!

 

I don't know much about the Ford or Mopar 400's, but the GM 400 was a piece of CRAP!! LOL

If you wanted a reliable engine and the 350 was not enough, you should have bought a 454. The 400 was a poor design with poor results.

 

In 71 the Ford 400 would smoke the tires forever in a car. They were torque monsters and everyone wanted one.

Engine specs for the 1971 400:
260HP @ 4400 RPM, 400 LB-FT @ 2200 RPM (Brake/flywheel figures)
Compression: 9.0:1
Carb: 2V
Engine code: S
Available in: Custom & C-500, LTD, Galaxie 500, Monterey

 

A lesson on rod lenghts, if anyone cares.



http://www.chevymania.com/tech/rod.htm