Big Block vs Small Block

[451Mopar]

So I've owned 2 small blocks and a 351 Cleveland which apparently is neither small block nor big block, but never a genuine big block. What am I missing out on? Is it the low down torque, different sound, more frequent visits to the gas station?
My 318 poly is pretty torquey and goes ok for what it is, but I have the horsepower bug and am always looking for more.
I'm thinking of slowly buying the parts and building a 440, and then doing the swap, maybe over a few years. I've never assembled an engine before but I like to learn new skills and I think it would be an achievement.
Good idea or not? Opinions welcome.

I like them all. As for building an engine for the first time, it is best if someone helps you who has done it before (and has some of the special tools.)
Building an engine with new parts is really different than "assembling" an engine (like a re-ring job) that was all together and running before disassembly because all those old parts fitted together at least once before.

I have been looking at the newer engines like the Gen III hemi because I like the modern technology (for a daily driver), and it is less expensive to get that technology on the newer engines than trying to retrofit it to the older engines.

 

[5.7 hemi]

For about 3k all in, you can retrofit efi on your current engine.

 

[67charger383]

Yes.

A small displacement turbo-charged engine can be the equal of a larger displacement normally aspirated engine.

True. there's also acceptions to

I like them all. As for building an engine for the first time, it is best if someone helps you who has done it before (and has some of the special tools.)
Building an engine with new parts is really different than "assembling" an engine (like a re-ring job) that was all together and running before disassembly because all those old parts fitted together at least once before.

I have been looking at the newer engines like the Gen III hemi because I like the modern technology (for a daily driver), and it is less expensive to get that technology on the newer engines than trying to retrofit it to the older engines.

Watch Tony DeFeo's videos about the gen 3 hemi

 

[rmchrgr]

Here's my take:
A body = SB
B body = BB
440'

Yep. Two factory exceptions to that general rule were the GTS 383 Dart and the '72 340 Roadrunner. Either way, it never made much sense to me that the factory thought it was just fine and dandy to put 2bbl 318s into behemoth, air-conditioned B body station wagons or long bed trucks but there were plenty of 'em out there. Guess once the car is rolling it's all the same but getting one of those things out of the hole in a hurry is an uphill battle with a lo-po small block.

Had a '71 Dart with a factory original 318 2bbl that could smoke the tires in low no problem but other than that, couldn't get out of its own way. The basically stock 383 in my Coronet is passable but just barely. It goes but it's nothing to write home about. The 5.7 Hemi in my Ram is a way better motor with less cubes in a significantly heavier and less aero vehicle.

Stock vs. stock, I'll take a 340 car over a 383 any day. To me, small blocks (at least the 340) feel more responsive than your garden-variety 906 head big block. Conversely, 340's have no low end but once they're past 3,500 rpm it's a different animal.

For comparison sake, the "small block" in my Duster has more displacement than the 383 in my Coronet and probably makes double the torque and horsepower. Lighter too. There are 500" inch small blocks out there, 440" is fairly common now.

 

[YY1]

I own and drive a 318-2 73 B body with AC.

60K original miles and 47 years of age. NOT restored or rebuilt.

No problem whatsoever laying rubber with the AC on or getting to 70+ MPH on freeway on ramps, or passing people while doing 75+.

None.

I've driven 318 B and even C body wagons and trucks.

Are they a 440, No.

Are they fine in today's traffic, Yes.

 

[66 Sat]

The new build has to be separate, so the car stays on the road. Otherwise I would consider stroking the poly, but yanking the engine and having the car sitting for potentially months is not the plan. I just want a project that I can do over time with low stress levels, buying or borrowing tools as required, learning as I go, getting help as needed. The poly is in great shape and could be sold after the swap, and would probably fetch good money here in Australia. I could also paint the engine bay body color when the poly comes out.

 

[VFilms]

The new build has to be separate, so the car stays on the road. Otherwise I would consider stroking the poly, but yanking the engine and having the car sitting for potentially months is not the plan. I just want a project that I can do over time with low stress levels, buying or borrowing tools as required, learning as I go, getting help as needed. The poly is in great shape and could be sold after the swap, and would probably fetch good money here in Australia. I could also paint the engine bay body color when the poly comes out.
View attachment 1028914

Just curious. What’s the carb and spacer. I may have to replace my WCFB for air cleaner clearance issues and the people at Edelbrock have not been particularly helpful.

 

[66 Sat]

It's a Holley 600 vac sec. Not sure on the spacer, it was needed to adapt the Holley bolts to the factory 4 barrel intake. I can find out what the make/model is later just need to find the receipt.

 

[Don Frelier]

I would consider staying with a small block. Otherwise you need to change the trans, exhaust and likely the drive shaft.
Can you find a 5.9 magnum? You can switch to a carb if you prefer and stick a Hughes cam in it. They run strong and last forever.

 

[Budnicks]

An RB or B series BBM
Compared to a Polisphere Small block/wideblock "Poly"
not much different dimensions or size under the hood
allegedly weights appr. 600+#'s

performance 101

BBM has the distributor up front easy to work on
any of the below has batter flowing heads

a base All-iron 273-318-340-360 LA version SBM is appr. 550#'s

a BBM Low Deck 350-361-383-400 B series is appr. 620#'s all iron
can be about the same as an all iron SBM/LA version,
if you go with a good/better flowing & aluminum heads
it's a wash in weight (compared to the Poly), add a few more aluminum parts,
ditch the iron water pump housing, exhaust manifolds & intake etc.
& it can lighter even yet

RB tall/wide deck early 383 (old-style) 413-426w-440 is appr. 670# all iron
again with some lighter parts, it can be lighter than that org. Poly is

Small block cars tend to handle a bit better
in stock form
modified either can be made to work well in any build
sway bars & good tires & shock will remedy that

torque is the biggest difference + stroke
(more stroke, generally makes more torque)
a tad bigger bore in the BBM's helps/aids in performance too
& flow (especially well-done heads) characteristic for when you do the heads
any engine big or small will/can benefit from better cylinder head flow
bigger valves, competition/multiple angle valve job,
more camshaft lift & duration, better intake/carb/s, better induction all together
hotter ignition, hotter coil, low ohm resistance plug wires (less than 100ohm per/ft),
an advance curve in the distributor, free-flowing exhaust
(especially good headers a H-pipe or X-pipe in the proper place)
free-flowing air-cleaner & gauze element/filter,
a good well-sorted prop. sized carb/s (again flow can be very helpful here)

more compression helps, but to a limit, especially on a street engine
if you have a really good well-sorted combo
the block has been cleaned out really well (rust & scale in the water jackets)
not bored out too far
a good hot ignition & well-sorted induction system (intake & carb/s)
& a good radiator/water pump etc.,
11:1 compression is very street-able usable

an engine is merely an air pump
with fuel & ignition added
the better it flows & burns the fuel fed to it,
the more usable the power is

if it has a TF auto,
the Torque converter needs to be matched to the driving style
& camshaft selection
TC can make or break the build combo too
the rear gear ratio needs to be taken into consideration
(3.73:1 to even 3.91:1 is a good compromise, performance & street-ablity)
depends on what camshaft & what RPM the engine combo
lower gears help move a heavy car, especially with a good converter combo
what will it be operating in ?
or what the final output that is desired ?

if it has a manual trans the rear gears are really critical
for the combo & performance, 3.55:1 min.
to IMO a steeper/lower gears like 3.91:1, 4.10:1 to 4.30:1
depending on rear tire diameter a 10:1 ratio combined in 1st gear
1st gear ratio x rear end ratio = appr. 10:1+

lesson 1 over

 

[451Mopar]

For about 3k all in, you can retrofit efi on your current engine.

I know the Gen III swap is not for everyone, and under hood appeal goes down when you expect to see the original style engine.
I'm just saying that from a cost and performance point it might make sense in cars that are driven alot.
It's not just the EFI swap/retrofit. The stock* Hemi heads flow more than most aftermarket big block aluminum heads. *Note: except for the 2003-2008 5.7L whic flow < 300 cfm.
The 6.1L heads flow 321 cfm, the 2009+ 5.7l Eagle heads flow 331 cfm, the 2011+ 6.4L Apache heads floe 340 cfm all stock, not even ported. This is about what a Trick Flow 240, and Edelbrock Victor big block Mopar heads flow.
Also, comes with factory roller cam and DIS Ignition.
Get a pull-out with accessories, and get modern A/C, high output alternator, modern steering pump, and serpentine belt drive.
I don't think there is much aftermarket support for the O/D automatic transmissions yet, but converting to a new O/D transmission is fairly expensive too.
Some of the pullouts do have manual transmissions too.

Here is a 395 HP 2015 5.7L with Tremec 6060 manual 6-speed transmission for under $5,000. Make an offer, they may take $4K? The 6-speed trans in new condition costs almost 4K.
https://www.ebay.com/itm/2015-Dodge...799058?hash=item595d250ed2:g:u7kAAOSw7ixfszaj

 

[1 Wild R/T]

I would try to track down an 89-92 360... Why? Factory roller cam!! The best OE small block heads Mopar offered... And a great base to build a 408 stroker.....

Here's the best deal I've found on what I consider the best stroker kit for building a 408...

https://www.cleggengine.com/scat-rotating-assembly-chrysler-360-408-i-beam-1-48035bi.html

The trans will bolt right up... Can't say that about a big block...

You can add a performance cam & re-use the roller lifters, with no worries about losing a cam due to the additives having been removed for oil...

A little work with a die grinder will wake those iron swirl port heads up... Or you could go straight to the many aluminum offerings...

Being in Australia isn't gonna make it any easier so why subject yourself to the extra challenge of a big block or gen III Hemi?

 

[66 Sat]

I'm hearing you all, but these are things to consider:
a. I don't need to do anything - the poly runs great, sounds good, doesn't run hot, gets 18 mpg on average. It's already built with performance in mind (within the limitations of its' size).
b. I'm only interested in building an engine in my spare time over maybe 6 months and then swapping in at some point - I'm not interested in just swapping in a different engine for more performance. I have to keep busy and have a project, learn new skills etc, idle hands and all that...
c. The engine has to have some historical appeal. The 426 hemi has it and is the ultimate (but too expensive), the 440 and 340 also have it. A 360 just doesn't do it for me.

I hope this makes sense and I thank everyone for their input. I'm just one of those guys who isn't happy with the status quo and is always thinking of the next thing to do or change. It gets tiring sometimes....

 

[moparedtn]

Watch Tony DeFeo's videos about the gen 3 hemi

...and then ignore them. There's literally millions of those engines out here in the
real world, plugging away daily - and of course, they're still building them, all the
way up to 1000hp from the factory.
I've had four of them over the years (still have 2 now) and nary a problem out of
any of them.

 

[747mopar]

For me it was BB hands down, I wanted plenty of power and excellent driveability, not a motor screaming down the freeway at 3,500-4,000 rpm. Typically (excluding any form of boost) smaller cubic inch motors will need to be spun much faster to achieve the same horsepower, as a result you run lower gears to keep the motor in it's happy spot and freeway cruising becomes miserable.

 

[66Satellite47]

I'd say it comes down to what you have available Down Under.
If you go LA small block, a 360 for street driving is just easier & better than a 340(which were great in the day), much better torque, the cast crank is fine at 6500 RPM maybe not 7500 or 8000.
With a BB, 400 is a bit better than a 383(big bore, more power), 440 is what everyone says, big torque. All the big blocks respond with BIG increases in torque & power with basic porting of most any of the OEM BB heads(use the stock 2.08/1.74 or the larger 2.14/1.81 valves), light weight alum intake, water pump get it closer to the SB weight.
Gen III Hemi's are fabulous, my 2005 Durango 5.7 goes like mad above 3000 RPM and does 16-19 MPG on the highway. Don't know how much work involved in that swap though.
See what you've got for parts availability and local expertise to help you. Good luck!!

 

[Hey-O]

The Mopar 360 is the easiest and cheapest way to build a fast small-block Mopar. It makes more power than the 318 and it's a lot cheaper to build than a 340. It's also the easiest to find which would be good for someone in Australia. After-market support for the 360 is great, and with the right parts, it can easily make 450 horsepower and still have great street manners. If you need more inches, it's easy to drop in a stroker crank and get 406 cubic inches. So with fun in mind, 360 is your best bet and as far as historical appeal, the 360 was re-casted with two more cylinders added and you have a Viper engine.

 

[66Satellite47]

I do agree with Hey-O, a stock 360 is an easy build. I built a 360 for my '76 Dodge long wb van tow vehicle. .020 over forged pistons, Comp Hi Energy cam, LD4B intake & Carter AFB aftermarket 650, headers, fresh 727 & OEM 11" converter, 3.21 gear. Made great torque & power to pull my 5700# trailer & car. The van (4700#)also could run as quick at the strip as my '70 Barracuda 383.
Still a big block guy though!

 

[Hey-O]

I get the big block thing!!!

 

[66 Sat]

Well I've decided to stroke the poly. I'm going for the 3.54" crank, to give approx 360 cu in. I've bought the rods - Scat Pro Comp I beam, so now I'm committed. I'm going to buy the crank soon and then find someone local I can trust to do the build.
While the engine is out I can paint the engine bay body color again so it should be a win-win.