408 Engine Question

[Kevin H]

Originally Posted by Ronald G. Stephenson

The 313 was a Chrysler Canadian engine, and the ubigutious 318 were manufactured by the millions. Your 340 is a small block Chrysler out of he same family, but is what is referred to as an LA engine.

The 340 is NOT the same family of engine as the 313 and 318 engines used by Bristol.

The 313 and 318 engines used by Bristol were "A" series engines, with a polyspherical cylinder head chamber. The engines are commonly referred to as "Poly" engines.

Chrysler then moved on to produce the "LA" series engines which had a wedge shaped head chamber. There are few, if any, interchangeable components between a 318 Poly and a 318 "LA" or wedge head engine.

Unfortunately, the "LA" series engine is commonly referred to as the "A" engine which causes much confusion.

[andyreid3]

Hey Kevin thank you for the reply. The engine itself is in amazing shape and still retains its forged crank, rods, and its original cylinder heads. A single rebuild on the engine using forged pistons from Mopar performance. All hardware is ARP on engine internals.

It is a very valuable engine and makes me not care too much about not having the 313 right now as the intake manifold on the 340 would probably pay for a rebuildable 313.

I only wondered as I have seen quite a few engine upgrades on Bristol cars and those seem to sell for pretty good money still.

[Bryn Tirion]

This is old, but I think worth a bit more input. I have always understood that since the Bristol factory was always willing to upgrade your V8 Bristol at a price, there is no penalty in value (or in exhibition) so long as you do something that they would have done. So putting in a later Torqueflite is fine, and putting in a 383 (for instance) would be fine. A 340 would not have been an option, as it was never fitted to Bristols, and is indeed a lumpy street engine and not a smooth cruising Bristol engine. I happen to think the 313 is a fine engine, developing 250 bhp at 4400 rpm stock from Plymouth Canada. They can be sourced easily in Canada, having been put in Plymouth Belvederes and Dodge Senecas among others, and even in combine harvesters (my neighbour has one in a Massey Harris combine). They could easily be booted up slightly to a 318, but keep in mind that this is an A engine and not an LA, as pointed out by others, so one has to be careful about the 318 parts and what hey are intended to fit. The 318 version of the A engine was put in a number of US market models also, between about 1958 and 1962.

[rkirk304]

I bought Andy's 408 last year.
It has needed some work on its steering and also the petrol tank. But the biggest issue has been its engine.
Luckily the 340 "six pack" is an object of great interest to Mopar nuts. With new inlet manifolds, pushrods and much work trying to get the carburetors right it now produces enormous amounts of power.
It is however a little corse, and doesn't like being smooth at 70mph, although pulls like a train beyond 100mph.
If anyone knows of good 313 or 318, I would be very interested in purchasing it. I live in the US, so shipping from Canada would be easy.
The 340 is quite valuable, and I have plenty of potential buyers for that.

[Bryn Tirion]

Originally Posted by rkirk304

I bought Andy's 408 last year.
It has needed some work on its steering and also the petrol tank. But the biggest issue has been its engine.
Luckily the 340 "six pack" is an object of great interest to Mopar nuts. With new inlet manifolds, pushrods and much work trying to get the carburetors right it now produces enormous amounts of power.
It is however a little corse, and doesn't like being smooth at 70mph, although pulls like a train beyond 100mph.
If anyone knows of good 313 or 318, I would be very interested in purchasing it. I live in the US, so shipping from Canada would be easy.
The 340 is quite valuable, and I have plenty of potential buyers for that.

I would happily place a wanted ad for you up here. I see you are in Massachusetts, I am located in Alberta.

If you want to find a 318 poly engine in the US, you should look for it in models that used the Carter AFB carburettor, to get the same level of performance. These cars would include the 1960 to 1962 Dodge Dart, including submodels Phoenix, Pioneer and Seneca, although the first of these is most likely to have that option. 1958 to 1960 DeSotos also had the 318 four barrel as an option. I don't have details on later models, but certainly up to 1967 these engines were still current in several models, and found in the Fury among others, and only replaced by the LA in all Chrysler divisions in 1967, although the LA was introduced in in 1964. Most of these poly engines have long since been replaced with something very like your 340.

PS. I have found one 318 in Las Vegas and one in San Jose. PM me if you want details of these. Both are cheap and look complete; the San Jose one was from a 1965 Fury and was running well when removed....... that one would be suitable, although it looks like a 2 barrel, but probably still a performance engine. There's even a video of it running in the car, and it does look and sound good.

[Thor]

I held off from posting on this when it first came up and I have tried to hold off again these last few days, but my petrol head has overcome my sensible head, so here goes :
While a Bristol of the period should have a polysphere 318 engine (original 'A'), and it really is a fine engine, if a little heavy, a 340 six-pack is among the best single cam carburettor V8 engines ever, and there is no shame in running one of these in any vehicle which will take it.
I would like to increase my car collection to include a Dodge Challenger of the period, carefully set up to handle (and ride) well on road, powered by a 340 six-pack. You can have a Hemi or a 440 Max-wedge, but the 340 gives all the power you need if you're not actually drag-racing, and is usefully lighter in the nose of the car.
Anyway, as others have said, the 340 will not be difficult to sell.
As to the originality question, I think these V8 Bristols are amazingly good cars to drive, even in modern traffic. I feel quite strongly that using more modern Mopar V8s and more up-to-date Mopar transmissions are very positive things to do, so that the beauty of the cars and the good qualities of the chassis can be used more frequently, if not daily, with the better economy, driveability, and emissions of the more modern drivetrain.
So you might consider rebuilding your 408 with a Magnum 360 with a 4 or 5-speed and lock-up transmission, its not that difficult !

[Bryn Tirion]

Remember that the OP was about an effect on value of the car with an original engine as opposed to the 340. There is indeed a positive value in having a Bristol-sanctioned drivetrain, which can be: a. a 313 poly; b. a 318 poly;c. a 383. The transmission could be either earlier or later push-button Torqueflite, or 727 Torqueflite. For 1965-level performance there is little to beat a poly engine. The 408 313 develops stock 250 bhp at 4400 RPM, and that is straight, unmodified 1958 Plymouth Belvedere with AFB. Bristol pretended they tuned it, but specs are Plymouth stock. The poly A engines developed about 15% more bhp with comparable carburation than did the later LA engines. They're just, as Thor says, heavy.

Since it is rkirk's car, he can do whatever he wants with it, but to fit in with the smooth, high speed cruising style of the car-as-built-in-1965, the 340 or other high cam engine is unsuitable, and a 360 is not a Bristol-sanctioned engine. At slow speed, these cars are meant to glide along almost silently, with just a subdued blub-blub from the tailpipes.

The early cast iron Torqueflites are heavy and run hot, and the aluminium 727 is a much better unit for those reasons. If I could keep the pushbutton operation, I would make the change, but I am not aware that you can.

As for making the 408 into a more modern drive, there lies the slippery slope we can easily get sucked down, and I've been that road myself. Your 408, almost no matter what you do to it, will not beat my 2004 Focus wagon with 2.3 litre Z-Tec engine to 60 mph (7.8 seconds), and that's not fast these days. So why bother? Keep it as a 1965 car and enjoy the ambiance. It still drives very well indeed, feels smooth and powerful, and will easily keep up with modern traffic under normal driving and at any legal speed, plus 40 mph or so!

[Bob318]

Originally Posted by Bryn Tirion

I would happily place a wanted ad for you up here. I see you are in Massachusetts, I am located in Alberta.

If you want to find a 318 poly engine in the US, you should look for it in models that used the Carter AFB carburettor, to get the same level of performance. These cars would include the 1960 to 1962 Dodge Dart, including submodels Phoenix, Pioneer and Seneca, although the first of these is most likely to have that option. 1958 to 1960 DeSotos also had the 318 four barrel as an option. I don't have details on later models, but certainly up to 1967 these engines were still current in several models, and found in the Fury among others, and only replaced by the LA in all Chrysler divisions in 1967, although the LA was introduced in in 1964. Most of these poly engines have long since been replaced with something very like your 340.

PS. I have found one 318 in Las Vegas and one in San Jose. PM me if you want details of these. Both are cheap and look complete; the San Jose one was from a 1965 Fury and was running well when removed....... that one would be suitable, although it looks like a 2 barrel, but probably still a performance engine. There's even a video of it running in the car, and it does look and sound good.

The older, 318 polysphere A-engine was still used in Canada for 1967 (US vehicles got the LA wedge-head engine that year). And as for carburetion, ALL 318 poly engines were two-barrel-only starting in 1963. But even that engine is a brisk, torquey performer. And as I said in another thread, factory and aftermarket four-barrel manifolds are all over ebay. Foiks like Hot Heads, Egge Machine, and Gary Pavlovich will also be glad to sell you hotter camshafts and other performance parts; Gary is among those who have bored and stroked the 318 poly V8 to over 400 cu. inches while leaving it stock looking outside, so there's another option.

[Bob318]

Originally Posted by Bryn Tirion

This is old, but I think worth a bit more input. I have always understood that since the Bristol factory was always willing to upgrade your V8 Bristol at a price, there is no penalty in value (or in exhibition) so long as you do something that they would have done. So putting in a later Torqueflite is fine, and putting in a 383 (for instance) would be fine. A 340 would not have been an option, as it was never fitted to Bristols, and is indeed a lumpy street engine and not a smooth cruising Bristol engine. I happen to think the 313 is a fine engine, developing 250 bhp at 4400 rpm stock from Plymouth Canada. They can be sourced easily in Canada, having been put in Plymouth Belvederes and Dodge Senecas among others, and even in combine harvesters (my neighbour has one in a Massey Harris combine). They could easily be booted up slightly to a 318, but keep in mind that this is an A engine and not an LA, as pointed out by others, so one has to be careful about the 318 parts and what hey are intended to fit. The 318 version of the A engine was put in a number of US market models also, between about 1958 and 1962.

Actually, the 313 and 318 A-series poly engines are essentially the same, save for a slightly larger bore on the 318. There was even a 326 version in 1959 only, and only in Dodges (this had hydraulic lifters vs. the mechanical lifters in ALL other A-series polysphere engines.

The 318 is most common and was in fact offered from 1957 through 1966 in the US and 1967 in Canada. They're easy and cheap to find and buy. And except for the pistons and pushrods, the bottom end is the same as later LA wedge-head 318s (1967 and up for US). Upgrades? The 318 A poly engine is strong to start with, including forged cranks and connecting rods. 1957-58 versions came with two four-barrel carbs and 290 hp; those dual-quad manifolds are plentiful on ebay. So are aftermarket aluminum four-barrel manifolds. HOWEVER, you're better off using an original cast-iron 4-barrel manifold, which is dual-plane for better low-end torque. There were even old Edebrock and Weiand triple two-barrel manifolds--a great option--though they're much rarer.

[Bob318]

Originally Posted by Kevin H

The 340 is NOT the same family of engine as the 313 and 318 engines used by Bristol.

The 313 and 318 engines used by Bristol were "A" series engines, with a polyspherical cylinder head chamber. The engines are commonly referred to as "Poly" engines.

Chrysler then moved on to produce the "LA" series engines which had a wedge shaped head chamber. There are few, if any, interchangeable components between a 318 Poly and a 318 "LA" or wedge head engine.

Unfortunately, the "LA" series engine is commonly referred to as the "A" engine which causes much confusion.

Actually, the 318 A series polysphere and later LA wedge-head versions (at least into the early '70s) use the same forged crankshaft, connecting rods, oil pump, water pump, timing gear, and many other bottom-end parts. Distributors interchange as well. Of course, the pistons and pushrods are different. And of course the heads and intake/exhaust manifolds. The blocks themselves are similar and use the same bore and stroke. The A-series poly 318 has a thicker block, however, versus the thin-wall block on the LA 318.

[rkirk304]

So the 340 is out and a beautiful 318 is sitting on the floor next to the car.
Does anyone know what number Carter 4 barrel AFB carburetor is the right one for the motor?

Thanks.

And to have wheels while the 408 is having an engine transplant, I have just bought a 1972 411. It arrives on the transporter next week!

[GeorgeG]

Sorry, only just seen this request. I believe that the 318 used the Carter 3131S AFB carb.

[Bob318]

Earlier versions used the Carter WCFB four barrel rated at roughly 425 cfm or something along those lines; in '60 or '61, they switched to the AFB. Today, for a relatively stock 318, you'll want the Edelbrock 500 cfm; go 600 cfm for a hot cam and other mods, but remember, it's all too easy to over-carburate!

Remember, too, that earlier manifolds designed for the Carter WCFB had a smaller based made for that smaller carb; you'll need an adapter to fit the later AFB or the essentially similar Edelbrock. Strongly suggest going with a manual choke if you choose the Edelbrock; much, much better control with foolproof operation.

[Bob318]

My feelng has always been that it's perfectly okay to make performance/reliability/practicality upgrades, and Bristols are no exception. Based on sheer horsepower per cubic inch, it's hard to beat Mopar's 340. Chrysler's threw everything they had at that engine, which puts out far more than it's rated horsepower (numbers designed to fool the insurance companies!).

That said, it's awfully nice to open the hood and see the engine that's meant to be there. As other commenters have noted, there are loads of 318s around for dirt-cheap. You can keep the stock forged cranks and con rods, or put in the entire bottom end from a 340. Growing interest in this "semi-hemi" V8 also means growing parts and value--another reason to stick with the A-series Poly.

While the dual-quad manifold from '57 and '58 Plymouth Furys looks nice, it's essentially a single-plane log manifold that turns the relatively thrifty 318 into a gas guzzler. And as someone mentioned, the most-common Weiand aluminum four-pot manifold is also a single-plane that reduces the low-end grunt these mills are known for.

Best option: An original, if heavy, cast-iron dual-plane manifold made from '56 thru '62 (on the US 277, 301, and 303 and Canadian 303/313 versions of this engine) with, say, a modern Edelbrock four-barrel or even a plug-and-play throttle-body EFI setup. And while you can go all the way over 400 CU IN, the best compromise seems to be boring the A engine out to 3.95 inches (like the '59-only 326) and, perhaps, stroking it to roughly 3.58 inches to bring nearly 360 cubic inches. Or simply leave the stock bore and stroke and enjoy a pleasant combination of torque and reasonable fuel economy.