Upgrade Suggestions?

[440Chauncey]

Well ive had my 68 New Yorker for about 5 years now and finally have the engine bay tore apart to fix some firewall rust. I figured while i was at it i might as well do some cheap upgrades to the engine. Its a low mile motor with about 20,000 miles and numbers matching. It has a rebuilt stock Holley 4bbl and stock manifolds. I wanted to see about maybe putting on a bigger carb or buying a carb package with two small edelbrocks with a dual quad manifold. But i figured if i would want to do any of this I would definitely have to do a cam swap. But would anyone recommend any good cams for this type of application. My goal is to make a little more power and add to the wow factor, the car already got upgraded with new magnaflow exhaust and 3.55 gears. I also got a Electronic ignition system that was new from the 80's. Would anyone recommend a good hydraulic cam that still wouldn't be to extreme and also a setup for a bigger carb or dual quads? Its a really clean body except for the engine bay, the car was covered most of its life until the past owners bought it and had the hood off of it to rob parts for his winnebago!!! So at that point the cowl had leaves and started to rot when it was put in wet storage for a year. But I want to make it run like a decent 440 and add to the wow factor a little bit if possible. Any suggestions would be appreciated!!!

 

[CBODY67]

Aim for something in the same neighborhood as the 440/375 cam in duration and lift. The Edelbrock 4bbl dual plane intake can help. No carb bigger than 650cfm, even the stock Holley might work decently well. Use the THICK OEM-style carb base gasket. NO need for 2x4bbls! The single 4bbl will work fine, no need for additional airflow capabilities over 650cfm range. Mopar Perf ignition kit with an MSD box, if not already done. Using the Road Runner open element air cleaner base on your stock air cleaner makes for an incognito open element air cleaner. Same filter element. Carb? the AVS2 is probably the latest, greatest thing AND is available in a 650cfm model. Might still be less than $350.00 at Summit Racing?

Make sure to get all of that rust taken care of.

CBODY67

 

[70bigblockdodge]

Magnum/super commando resto cam, if you can find one. The Mopar Performance stuff is out of control$$ wise. Comp makes a similar one, they also make a cam one bigger (lift in the 470+ range) , I have one similar to this in a 440 and it has 15" at idle and good bottom torque still, definitely not a smooth idle though. It would probably be okay with stock converter and those IMO worthless rear gear.

 

[CBODY67]

Also Lunati's interpretation of "modern performance" too, fwiw. Even what MP sells as "resto" might not be an exact copy of the pure original, but what the original came to be a few years later. All the way into the 1978 model year, the service manual still lists the top 440 cam with specs close to what the earlier ones were, in the 1972 time frame, which usually had a few degrees more duration, a little more lift, and a few degrees more overlap. These cams should be pretty decent, but as they were in 8.2CR motors and in the general "advancing smog" era, probably not considered due to that fact. Might be better in a 9.5CR motor?

As a "side note", if a company sells a cam "equivalent to ________" factory cam, it's NOT the exact same, but close. Usually a little bit wilder in duration, lift, and overlap.

 

[Davea Lux]

If you are going to do a mild to moderate performance build for this engine, some things work well some do not. Start by removing the heads and take them to a good machine shop and have them ported to the magnum configuration with the magnum valve springs. While you are at it have the machine shop do the valve work so the engine will live on today's crap gas. Updating to the high performance magnum exhaust manifolds will help get the most out of the updated heads. I like the "stock" or close replacement magnum configured camshaft for a daily driver on the street. This eliminates having to go to a higher stall speed torque convertor and will also give you enough vacuum to run the power brake booster.

With the updated heads, exhaust and camshaft, you should be able to run an aftermarket AVS on the appropriate Eddy manifold at 750 CFM. Out of the box the AVS will probably need some metering rod adjustment and maybe a primary re-jet to get it to run right. These modifications are going to drop your current fuel mileage to 9-10 mpg if you are running 3.23 gearing but should bring the horsepower up to around 365-370 with a performance configured electronic ignition. If you are going to replace the camshaft, use the opportunity to install a steel timing gear set. Discard the plastic gear stock timing chain regardless of condition and regardless if you replace the cam or not.

That covers what "works". Dual quad setups were never a very good option for a street engine. An appropriately sized single carb will usually run better, be more fuel efficient and less troublesome. Once you start getting into high lift, high duration camshafts you run into problems with needing a high stall speed convertor and the appropriate valve body and shift modifications for the transmission, not usually a good option for a 4500lb street machine. The higher stall speed will also drop fuel mileage another 2-3 mpg. You will also need to install a backup vacuum pump and vacuum canister to get enough vacuum to run the brake booster and vacuum accessories.

A lot of this stuff depends on your personal preference and budget. You will have something in the neighborhood of $1200 just in the head work before you start talking about manifolds and carb setups. If that is not a realistic option for you, stay with a 600 CFM carb and a good quality electronic ignition system..The 1975 stock mopar unit works well and is still available in repop from several vendors.

Dave

 

[bajajoaquin]

The factory cam specs are a lot different from the aftermarket. Several guys here have the 375hp cam and really like it. It’s got really long duration but also really wide LSA. If you go aftermarket, don’t try to duplicate the duration. Stick instead to something under 220 degrees of duration at 0.050” lift.

 

[CBODY67]

The "wide" LSA of about 114 degrees is where most stock cams are. This is one reason they have good idle vacuum, compared to the more common 110 degree LSA.

CBODY67

 

[70NEWYORKER]

ported to the magnum configuration
Dave

What is this "magnum porting" you speak of...?? 1968 BB heads were open chamber 2.02-1.74 valve heads...

 

[bajajoaquin]

The "wide" LSA of about 114 degrees is where most stock cams are. This is one reason they have good idle vacuum, compared to the more common 110 degree LSA.

CBODY67

The specs I've seen show an LSA of 115 and durations well over 220 degrees on the factory cams. The aftermarket cams which are for a similar performance range tend to be at or under 220 degrees and have LSAs of 113 degrees. I'm not expert enough to tease out the compromises, but it looks to me like Chrysler made a different compromise with than aftermarket cam grinders: what they lost on idle and vacuum with the long duration, they gained back with LSA.

All I'm saying is that if you look at a 440-375 cam and see a 0.050" duration of 230 degrees, don't assume that you can get a Lunati or Comp cam with similar duration and expect it to have the same off-idle torque.

We are in agreement about an LSA of 110 being too tight, although I'm unable to offer a strict technical reason why I believe that to be true.

 

[Davea Lux]

What is this "magnum porting" you speak of...?? 1968 BB heads were open chamber 2.02-1.74 valve heads...

You are correct, there was a commonality of the High performance 915 open chamber heads. The main thing that needs to be done is to clean up the castings to remove any rough spots that will cause turbulence and size the intake and exhaust ports to the manifolds for the same reason. (The low performance 350 hp heads have the same casting number but 1.60 exhaust valves for 1967) The later heads 906's for '68 were produced in a stock configuration with the 2.08/1.74 valves also, either is a good performance head. Some engines for 1968 also had #2951250 or the 250 head, if memory serves me correctly, that head appeared on some of the lower performance versions and took more work to clean up the ports even though it still had the 2.08/1.74 valving.

The Mopar engines equipped with the high performance exhaust usually had the exhaust ports milled out at the factory to a larger size. The Dodge Magnum and Police cruiser engines were so outfitted, hence the reference to the Magnum configuration. even though this term appeared after 1968. The later Magnum heads also had dual valve springs.

Dave

 

[CBODY67]

The ".050" duration was not measured or considered when the Chrysler HP cams were designed.

After the .050" duration became an "aftermarket industry standard" for cam spec comparison, I believe that then-Mopar Perf operative Larry Sheppard said that to get to the .050" duration on a factory Chrysler cam, to multiply the "advertised" duration by .80 to get the approximate .050" duration (one year at the Mopar Perf seminar at a Mopar Nats, later '80s). There WERE/are SAE specs on how to measure duration, though, from "open" to "close", and that's what the factories generally used (although in a few years in the '60s, Chevrolet did tend to inflate things by including "the ramps" on the lobes rather than after the lifter was on the early lift "ascent/descent" part of the lobe.

Aftermarket cams didn't necessarily have to abide by the SAE method, so one cam with advertised duration might be 295 degrees and really be more like 275 degrees. Using the .050" lift spec gave all of the aftermarket cams a common place to measure valve timing events.

Last time I looked, Mopar Perf had BOTH the original-spec cams and a separate Mopar Perf line of cams (many with 110LSA).

Also be cognizant that cam duration has a definite relationship to CID, in how the engine "acts". A cam that works well in a 383 might be more of a "torque" cam in a 440. A "torque" cam in a 440 would be "wilder" in a 383, for example. Yet in the particular cam's description in the catalog, they act like they'll be the same in all sizes of the particular engine family.

Duration numbers don't always tell the whole story, all of the time. IF the intake valve opens a little earlier or later, it can still have the same "open" duration. Same with the exhaust side of things. Then there's "overlap" and lift.

The tighter LSA, I believe, moves the torque curve a little higher and the 114-area moves it closer to idle. With a lighter car and a deeper rear end ration, this might not really matter, BUT in a heavier car with "highway gears", off-idle response will be affected, by observation. A dual-plane intake vs single-plane intake can be factors, too.

Lots of factors . . .

CBODY67

 

[moper]

Sorry Dave - no factory head on any engine came with ported cylinder heads. Even the Hemis. The manifolding themselves is different as the years go by, and the 68-71 hi-performance ones are the best. But again they are all served up "as cast".

OP - if it was me I'd use the Comp XE256. Put a true dual exhaust system on it, and a modern ignition with a vacuum advance. Set the dual quads up with progressive linkage, and it will idle well, pull strong with any gear, and make some good steam.

 

[Davea Lux]

Sorry Dave - no factory head on any engine came with ported cylinder heads. Even the Hemis. The manifolding themselves is different as the years go by, and the 68-71 hi-performance ones are the best. But again they are all served up "as cast".

OP - if it was me I'd use the Comp XE256. Put a true dual exhaust system on it, and a modern ignition with a vacuum advance. Set the dual quads up with progressive linkage, and it will idle well, pull strong with any gear, and make some good steam.

No, they were not ported, did not mean to imply that they were. The HP manifolds and heads did have larger exhaust ports than the standard 350 horse engines. Don't believe me, try measuring a set of each. (This would be on 68-71 heads) You could clearly see the difference when looking at a T-Code with log manifolds versus a U code Police cruiser or Magnum engine.

Dave

 

[PontiacJim]

"The tighter LSA, I believe, moves the torque curve a little higher and the 114-area moves it closer to idle."

Ah, camshaft selection. Gets real confusing trying to understand all the terminology and then sort it out as it relates to your choice. I have studied this for some time in an effort to understand cam specs in selecting the cam for my build.

Lobe Separation Angle (LSA) - Lobe separation is the distance in camshaft degrees that the intake and exhaust lobe centerlines are spread apart. This separation determines how peak torque will occur within the engine’s RPM and power range. Tight lobe separations, such as 108° or shorter, will cause the peak torque to build earlier in the RPM range and peak-out in a short amount of time. Broader lobe separations, such as 112°, will start making that torque peak later in the RPM range, but this allows the torque to build over a wider RPM range. Broader separation angles produce increased idle vacuum for power brakes, idles smoother, and has better low end performance.

Automotive manufacturers use the SAE (Society of Automotive Engineers) J604 standard in defining cam lift which states that automotive camshafts should have their duration measured at .006” lift at the valve. On pushrod engines, lift at the valve is the product of (“cam lobe lift” x “rocker arm ratio”). Most popular pushrod engines use rocker ratios of 1.5, 1.6 or 1.7. When you divide .006” lift at the valve by any of the popular rocker ratios, you come up with .004” when the answer is rounded to three decimal places.

So in an attempt to comply with the SAE (Society of Automotive Engineers) J604 standard, some leading cam manufacturers measure the “Advertised Duration” of hydraulic lifter camshafts at .004” lifter rise on the cam lobe while others measure their advertised duration at .006” lift on the cam lobe. But, using .006” lift at the lobe (“cam lobe lift” x “rocker arm ratio”) results in at least .009” lift at the valve which is quite a difference from the SAE standard of .006” lift at the valve.

Years ago, the method of comparing cams by their duration at .050” of lifter rise was developed. This has become an industry standard, and the term “duration at fifty” implies the duration of the camshaft lobe between .050” of lifter rise on the opening ramp and .050” distance of the lifter from returning to the base circle on the closing ramp. Engine builders familiar with various cams have come to recognize that a cam that is 204 degrees at .050” is a mild street cam, and one that is 244 at .050” is a serious street/bracket race cam.

 

[CBODY67]

Although ANY cast item will have "parting lines" where casting flash can happen, there will need to be some light grinder action to clean things up for use. If the sand molds might have moved during the casting process, it might be possible that whomever was working the die grinder would remove casting flash AND "save" the heads by some additional grinding action where the problem might have been. Be that as it might be.

CBODY67

 

[70NEWYORKER]

No, they were not ported, did not mean to imply that they were. The HP manifolds and heads did have larger exhaust ports than the standard 350 horse engines. Don't believe me, try measuring a set of each. (This would be on 68-71 heads) You could clearly see the difference when looking at a T-Code with log manifolds versus a U code Police cruiser or Magnum engine.

Dave

From model year 1968 thru 1970 there was ONE part number For big block heads -2843 904. One head for all. Manifolding (intake,exhaust) was different depending on application and horsepower rating.

 

[Davea Lux]

From model year 1968 thru 1970 there was ONE part number For big block heads -2843 904. One head for all. Manifolding (intake,exhaust) was different depending on application and horsepower rating.

That is correct, there were two casting numbers, but both referenced the same Mopar part number (Casting numbers were 2951250, 2843906 this was '68 only) 69-70 are all 2843906 castings.

Dave

 

[bajajoaquin]

The factory cam specs are a lot different from the aftermarket. Several guys here have the 375hp cam and really like it. It’s got really long duration but also really wide LSA. If you go aftermarket, don’t try to duplicate the duration. Stick instead to something under 220 degrees of duration at 0.050” lift.

OP - if it was me I'd use the Comp XE256. Put a true dual exhaust system on it, and a modern ignition with a vacuum advance. Set the dual quads up with progressive linkage, and it will idle well, pull strong with any gear, and make some good steam.

COMP Cams® - Xtreme Energy 256 Hydraulic Flat Tappet Camshaft, Part # 12-234-2 Dyno Sheet
212/218 degrees of duration (I/E).

 

[The Goose]

Throw in a 509 cam and drive it like a race car with both feet in traffic to keep it from dying with the automatic in drive !!!

Just kidding, you might hit up one of the Old Direct Connection Dealers in your area some are still around but they are all private shops now. We have Dennis Mauer in Tempe Az and he's a wizard at what your asking for. 60+ years of hi perf experience at your fingertips. Mauer's Performance on river in Tempe az. Look up his number on google maps. He's the real deal. Happy hunting...

 

[The Goose]

That is correct, there were two casting numbers, but both referenced the same Mopar part number (Casting numbers were 2951250, 2843906 this was '68 only) 69-70 are all 2843906 castings.

Dave

Everybody I know wanted the "906" heads. Open chamber ???? I don't remember, I stuck mostly to 340 stuff.