I do think that the quench was a good thing for every motor - except for the emissions. With quench as Detroit had it implemented, unburned fuel remained in the quench section, which boosted emissions. However, it sure enough did help power, because quench allowed a higher compression to be run. When the quench was removed, engines of the mid and late 70s were notorious for run-on after being shut off, even with their low compression.

My belief about SBC emissions has to do with their lousy spark plug placement, not the presence or absence of quench. The plug is about as far away from the center of the chamber as it is possible to place it, and then it is also at the lowest part of the chamber, ensuring that if there's any liquid fuel in the chamber, it will manage to wet the plug. Ed Cole & company did a fine job laying out the ports for the SBC, but they did not pay as much attention to chamber design as Ford did.

It is interesting to note, going back to the subject of quench, that it is back and common enough. Many 4 valve engines use a tiny area of quench on each side of the chamber, one area between the intakes and the other between the exhausts. This alone is sufficient to induce the turbulence that is quench's reason for existence, but the small area keeps unburned pollutants from forming in excessive quantities.

Of course, another benefit is that the plug can be placed squarely in the middle of the chamber, and at it's highest point, to boot.

Regarding carbs, I would like to say that we all have our opinions and favorites. For me, the Holley 4150-4160 design has proven to be the best. I do realize that some people favor Q Jets and even Thermo quads for their spread bore configuration and small primaries, under the theory that the small primaries allow finer metering and thus better mileage.

It has never worked out so for me. My old 77 Chev Stepside with a 454/TH400 always got superior mileage with a 1850 Holley 600 cfm than it ever got with the original Qjet. I think that, with the Qjet design, it is the best way to get decent mileage cheaply. But more money and a cleaner design makes the Holley a more efficient and superior unit, in my mind. Just looking down the primary bores of a Qjet, with their fat throttle shafts and crude, gross castings makes one wonder how any air can flow thru them at all, while the secondaries resemble a pair of tomato cans with a gas soaked rag wrapped around them.

There were/are several other endearing qualities of Qjets that I have not cared for:

1. The solid floats that WILL get fuel logged sooner or later -- and the small float bowl that rules out their replacement with a proper brass float.

2. The poor power valve piston/cylinder design. I've never had a problem with this sort of design in AFBs or Thermo quads, but on Qjets, I've run into a number of the units where the power piston would stick in the rich position, no matter how many times efforts were made to correct the problem. Envision this: Ever push a 1968 Olds 98 across busy highways because it was flooded out and would not start? Not fun.

3. Every Qjet vehicle I've ever had always ran better with a Holley. Qjet vehicles always required more cranking to get them to start and always felt much less "snappy" to throttle input, especially when driving about town. One would think those small primaries with triple venturis would be the snappiest combination of all, but this was never my experience.

Everyone has their favorites, and I'm only relating my own experiences, not trying to say anyone whose mileage differs is wrong. Everyone's always much more convinced by their own experiences, as opposed to the arguments of others...

On the big/small block discussion, I'm not sure how the bellhousing pattern can determine whether an engine is a big or small block. As has been correctly pointed out, "Big Block" and "Small Block" are Chevy terms, not Ford terms, but even still, the argument of bellhousing patterns seems to loose some force when one recognizes that both big and small block Chevies use the same bellhousing pattern!

On other aspects of this big block/small block business, I'd note: The nail head Buick motor had 2 deck height increases: once with the increase from 322 to 364 inches, and again when the 364 was increased to 401 inches. Given that the bore of this engine reached 4 5/16" in the 425, they are hardly "small blocks," but they are quite compact for such a large engine, due to their short strokes and odd head/valve gear configuration.

It's probably best to leave the big and small block thing with Chevy, tho I suppose good arguments could be made for the modern Buicks, e.g., 300/340/350 vs 400/430/455. (But I would note that they all shared the same bellhousing pattern, too!)

The modern Olds is a bit more complex: there's the 330/350/403 vs. the 400/425/455. This comparison is most similar to the B vs RB Chrysler, in that the difference is chiefly deck height, rod length, stroke and main bearing size. One never thinks of a 383 being a small block and a 440 being a big block, however, does one? (and of course, both the big and little Olds motors share the same bellhousing pattern, as do the B/RB Mopars).

Everyone knows that a SBC and a BBC are different motors -- but one also knows that a Cleveland is a 335 motor -- different from a 385 motor, and FE, a MEL, a Windsor, or a 90º. I don't see how "Chevy-izing" Ford nomenclature adds any value or precision to the discussion, personally, but hey, if that's what someone wants to call them, whatever.

 

I don't agree. I know our 396 Impala couldn't pull high revs in top gear, with it's high axle ratio. It was in essence...overgeared.
In theory something like a 2.56 axle should give an amazing top speed.....but the problem is that with a three speed automatic and a 1 to 1 in third gear....even a torquey big block will have trouble overcoming that high gear to reach anywhere near it's theoretical top speed .

In fact I wouldn't be surprised to learn that a car with a BB, a high axle ratio and a three speed with a 1 to 1 in third...would have a higher top speed in second, rather then high gear.

 

I've always gone by bore spacing as the delimiter between "small" and "big" American passenger car and light truck V-8's. Many engine families have short and tall deck versions. Its not a brand thing at all. I totally agree that bellhousing pattern has nothing to do with it.

I also dont think that GM ever used those terms officially for Chevrolet engines, so its all informal nomenclature, GM divisions, Ford, Chrysler or otherwise. What GM upper management did in the 1960s was put an artificial limit on engine size in "compact" cars due to safety "image". So, a 1964 Pontiac Tempest, which was bigger and heavier than a 1954 "full sized" Pontiac, was not allowed to have a 389ci version of the same engine family as the 326ci V-8. From a non-technical (marketing) standpoint, 326 is "small" and 389 "big". John Delorean disobeyed and the rest is history.

 

Yes, De Lorean disobeyed -- he got away with that infraction, but not a later one related to his automotive career :-( -- but the path was not totally untrodden. Back in the late 30s, when Buick had a "big block" straight 8 for its Roadmasters and a "small block" straight 8 for its Specials, they put the big 8 in a smaller body and created the Century, which was one of the better performance buys in the USA before WW2.

This doesn't take away from what De Lorean did, but it does point out that he had some automotive historical precedent for what happened over at Pontiac in 1964.

I might also point out that the 326 in the Pontiac Tempest wasn't always a 326: There were actually two V8s that Pontiac called 326, but the Tempest V8 of 1963 was actually 336 cu in, 3.78" bore x 3.75" stroke (the 336 Pontiac engine used in GMC trucks in the 50s had a different bore and stroke). In 1964 and later, the 326 was a true 326, with a 3.72" bore x 3.75" stroke. This is, perhaps, a somewhat trivial point (unless one is ordering a set of pistons and rings for a 1963 Tempest), I agree, but it really is no different than the similar 396/402 BBC issue.

Back to Buicks, my Dad had, after WW2, a 1939 Buick Special demonstrator. This Special had the big 320" Roadmaster swapped into it by the dealer, so that customers could be wowed with the performance of the Special...

There really isn't much new under the sun after all.

 

I witnessed a race a few years ago between a 72 caprice with a 400 turbo 350 and 3.08 and a 74 LTD 400 c6 and 3.xx. Dead stop quarter mile run, my god was that the longest 1/4 of my life. The chevy took the lead from the start and held 2 car lengths the whole time. 20 minutes later i had the heads off the chevy porting them dropped a 4 bbl holley on it and its still fryin tires today at 124000 miles and purrs like a kitten. On the flip side ive fragged several stock 400 chevys in 4x4 trucks and my buddy still has the original 400 Ford in his late 70s F250 and its rolled the odometer at least once since hes owned it. Im a chevy guy but ill admit the ford 400 is a better truck engine it has a better bore/stroke combo at 4"x4" over chevys 4.125x3.75 but for racing id go with the chevy still have one runnin the stock 5.56 (short) rods a set of KB hypers and a nodular iron crank spent alot of money to get it balanced superbly and its seen 8500 revs more times than i care to admit and it holds together just fine. the overheating from the siamese bore wasnt as much a block design fault as not redesigning the thermostat to compensate for the close wallsdrill a 1/16 inch hole in the stats flat surface as a type of bypass and no more over heating.How do i describe hot rodding a ford 400. never tried it the 4" stroke made me leary plus the expense over a chevy could it do the same things im sure it could anythings possible with the time and effort put into it

 

stock for stock both were good engines but not a powerhouse. A 400sbc is far cheaper to build horsepower with. A 400 ford is a good truck engine. I know jon kasse made around 600hp I believe with a 400 and 4bbl clevland heads I believe, don't hold me to it. For a truck engine I would say they are close but for performance the chevy has it. imo

 

As long as we now have both a 400 Ford in a 1977 4x4 F-350 at my shop and the 93 Chevy ex cab 4x4 Dually we can put this to the test.
The Ford is .030 overbore, has a .214/224 @.050 cam, Wieand Intake, Summit headers and distributor with 2 1/2 Dual exhaust with H pipe. C-6 and 4.10ish gears. It smokes the Duals with ease. My former landscaper brought it to me for a complete restofication and will be here 'till spring.
The Chevy is one of our lawn mower tow vehicles, was a diesel, Had Caddy power for the past 2 yrs and fuel expenses dictate smaller engine now. Went to boneyard looking for 425 Caddy but no luck, Had a recent rebuilt sbc 400 4V, runs good for 5 bills so I took it. The plan is a Summit 1103 cam(same .050 duration as Ford), Offy Dual Port Intake, shorty headers, 2 1/2 to 4" y pipe to 4" Mandral bent exhaust and a KMJ distributor. It has a 4L80E trans, 4.10 gears and a TCI trans ECM.
We will test both with the on-ramp mph test, hook the 7500 lb mowing trailer up and re-test and check mpg and post it all here.

 

Rickpilgrim, while I would love to see the 400 Ford win this competition (what the heck, it's gonna win anyway), you are seriously handicapping that 400 Chevy with that Offy Dual Port intake. Respected engine guru David Vizard showed in a massive 1984 or 1985 Hot Rod intake manifold dyno shoot-out that the Dual Port is truly awful for power production. I remember it was one of the worst manifolds if not THE worst for horsepower and torque. Please give that Chevy a fighting chance and give it a proper modern dual plane so that the Ford's victory won't be a hollow one!

And speaking of that Ford, could you please specify which Wieand it has? Might need to re-examine that intake too.

We also need to keep in mind that the Chevy's 2 1/2 to 4" y pipe to 4" Mandral bent single exhaust system is probably the better set-up for the low and mid-range torque that is so needed for towing weight up a grade. Maybe you can talk that Ford's owner into doing an upgrade!

Everybody here is aware that it's a 400 Ford that keeps winning the "Engine Masters" challenges year after year not the Chevy 400 right?

Even when upgraded to the longer 350 SBC connecting rods, the SBC 400 still has the WORST ROD LENGTH TO STROKE RATIO OF ANY V8 EVER PRODUCED!!! This adversely affects everything from fuel economy to engine longevity to power and torque production. Short rod ratos suck!!! If short rod ratios were the hot ticket, more V8s would have them. THEY DON'T!

Can't wait to see how this competition turns out!
Regards, Eric

 

Offy dual port, my god, I didn't think there were any of them left! I used one back in 66 or 67 on my 64 Falcon 260ci engine with one of the newest carburetor designs out, a Quadrajet. I finally ended up with a Ford pre-muscle parts setup, 3 2V Holleys. To a 20 or 21 year old who was just learning, the Offy dual plane sounded great, in retrospect, how does taking a 1/4" I think it was slice out of the center of your intake port help, that and the "360 degree" design means poor distribution.

Engine masters, I didn't realise the Ford 400 was doing that great, I have a friend who owns a local shop, he and his son are both "bow tie" guys, they like the 454. They had their butts handed to them when the test program got changed a few years ago by a 460.

 

It's not quite that simple. the AMC 290-401, which most everybody considers to be a small block, has a larger bore spacing than several big blocks and so called big blocks including but not limited to the Pontiac, the Olds, the FE Ford, and is in fact exactly the same as the big block Buick! It does have a short deck height though: 9.208" at it's tallest point in it's production lifespan, basically the same as the 9.206" Cleveland deck height. Meanwhile, !he 400 Ford, which we all know is a small block, has a taller deck height than many big blocks including but not limited to both of the Chevy big blocks (the 9.8" "pass" blocks and the 10.2" "truck" blocks), the FE Ford, the 350-361-383-400 "B" Mopars, the Pontiac 287-455, and others and is in fact virtually the same as the 385 series.

The Buick 340s and 350s, which are definitely small blocks, in that they have the smallest bore spacing of any of the 60s-70s V8s, also had a deck height that was larger than several big blocks. A tall deck height makes an engine tall AND wide making for an engine that takes up a lot of room under the hood, just like a big block does. A very good example of this is just how big the Buick 350 is and how hard it is to tell the big block Buick 455 from the small block Buick 350 when they are sitting in their engine bays! Try it some time! (La Sabres came with both so that would be a good model to do your "test" with.) There are a few dead giveaways but most folks don't know about them! (It also doesn't help that the heads on the 350 are almost a perfect copy of the 400-430-455's heads!) The "tallness" and "wideness" of a tall deck height V8 really jumps out at you much more than the "longness" of a large bore spacing V8 does. (The AMC being a great example, it's a very compact engine!)
Regards, Eric

 

The 454 Chevy has the second worst rod length to stroke ratio of any V8 ever made. Another vastly over rated engine.

Back on that Offy: Yes, that "360 degree" design is also gonna hurt low end torque production and in this application it will hurt, not help, the truck's ability to pull that trailer up that ramp. That was the funny thing about the manifold shoot-out: nowhere in the rev range did the Offy out-perform even the stock intake! Pretty sad!
Regards, Eric

 

Wow, after over a year and 4 pages of info, and I still don’t think this original question has been answered.
<O</O
“after reading the arguments about the 460 vs. the 454 I got to thinking about this match up. A Ford 400M (true displacement 402) vs. a 400 sb Chevy"
<O</OWhile yes there has been a lot of great information posted, and some people have been taking sides, but how about a simple answer to the question. Using stock engine numbers, either factory supplied or, preferably, from independent testing (as factory numbers may be skewed for insurance, emission or marketing reasons), give us the best numbers (best years) for; ???HP (<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com</OWhile this might be comparing apples to oranges, as one motor may be designed for low rpm torque in heavy vehicles as the other may be more for higher rpm horse power passenger vehicles, the reader should be able to figure that out by the numbers.
<O</OI also realize that one year may be more “smogged” or have more accessories driven when tested. And of course once you start modifying the engines, all stock numbers can go into the dumpster as then anything is possible with any engine depending on how many “Cubic Dollars” you pour into it.
<O</OAs for the 400, to M or not to M, Who cares! My understanding was the M was for modified as in smogged. That the M engines were <st1:City><st1lace>Clevelands</ST1lace></st1:City> with lower compression ratios, retarded cam timing and modified heads that were internally ported for the air injection system. Maybe I was misinformed but I don’t claim to be an expert on it.</st1lace>
<st1lace><O</OAs for the Ford 400 being a big block, while yes it has the same bell housing bolt pattern and may use the same motor mounting, but I understand the 400 weights 125 lbs less than the 460, for whatever that’s worth.</st1lace>
<st1lace><O</OAs to the great 1979 F250/CK20 race. Again this is apples and oranges in the motor area. The Ford 400 is a long stroke, low rpm, torque motor while the Chevy 350 is more of a free revving HP motor. Additionally the Ford came stock with a 2 barrel carb the Chevy may have come with a 4 barrel. I wonder how the race would have played out if each truck had 500 lb in their beds and were pulling 5000+ lb trailers.<O</O
<O</O
</st1lace>

 

Yes, the Ford is actually a 402 and the SBC is actually a 401.

All three 351s are actually 352s but they are called 351s to differentiate them from the 352 FE! They all have the exact same bores and strokes!

The 351"M" was called "M" to differentiate it from the 351 Cleveland and 351 Windsor because it was different enough from the other two that it needed to be differentiated. The 400 had no such need because there weren't any other 400s for it to be confused with. Just call it a 400.

I've already addressed why the 400 Ford is a small block a few posts ago.

I think in some years Ford retarded the cam timing via the the chain and gears, and in other years they did it via the cam itself, so for this comparison to be fair, the Ford's timing chain, gears, and cam need to be replaced to eliminate the retarded cam timing, a 4 bbl carb and an accompanying dual plane intake need to be installed, and, to be fair, the Chevy needs to be allowed to run a similar 4bbl intake and cam. In other words, if the Ford gets to run a "Performer" intake and cam, then the Chevy gets to run those too.

I stand behind my position that the 400 is superior in every way, and even the Chevy 400 lovers would have to concede that the super short rod ratio of the Chevy 400, again, the worst ratio of ANY V8 EVER MADE, takes it's toll on cylinder wall wear, piston wear and ring wear. Even if the Chevy wins the race (and again, I maintain that it won't) I'll still take the Ford cause it will live longer and that is the most important race of all!
Regards, Eric

 

The 402 was aval. standard in first gen monte carlos as well as pickups

 

Over the years (getting close to 30) I have been in the business, and all the small block Chevy's I have had apart (including some really high mile examples) I can't say I have seen any more cylinder wall wear in them than any other engine. Valve guides were another story.... Recently, I asked the opinion of a well respected engine builder (and Mopar nut) his opinion of the whole rod ratio theory. He said in a naturally aspirated street engine, it made no difference whatsoever. He did have some interesting comments, though. First, a longer rod usually means a heavier rod, and you always want the lowest possible reciprocating weight. Second, a longer rod means more piston dwell time at TDC and BDC. That will make an engine more prone to knocking, and also means a heavier load on the rod bearings. This engine builder said that rod ratio becomes quite an issue in blown or engines that use nitrous because of piston dwell.

The statement about long rods making an engine more prone to knocking is interesting, considering all the trouble Ford had with knock in the late 70's 351M and 400 light truck engines. I know a lot of it had to do with the cylinder head, but one has to wonder if rod ratio played a role in it. Those engines were really anemic.

I still say the 351W was a lot better than the 351M or the 400. The later 335's couldn't take much overbore (.040 max, if no core shift), and the oiling system left a lot to be desired.