400 engine rebuild | 2bbl -> 4bbl | more power | part questions

ayilar

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Interesting thread. @71Polara383 is helping me improve the 440 in my 1973 NYB -- her engine has two bent rods, so we might as well fix things "right" while we are at it. Nothing crazy, just getting her engine to have a bit more pickup. Will post in the thread I keep for Ming.
 

71Polara383

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Interesting thread. @71Polara383 is helping me improve the 440 in my 1973 NYB -- her engine has two bent rods, so we might as well fix things "right" while we are at it. Nothing crazy, just getting her engine to have a bit more pickup. Will post in the thread I keep for Ming.
Bent pushrods not connecting rods. To be clear.
 

71Polara383

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Somebody tried to start it with bad gas?
Well the previous seller (derby guy on FB) had told us he had it running and driving on a remote tank. Turns out...he may have had it running and driving, but never from a remote source. Good thing is it didn't run much like that and hasn't suffered extensive damage, seems to be just limited to the valvetrain, I could have probably popped a set of pushrods in it, and been on the road but, a refresh over the winter will have her up and moving by spring with no questions concerning the unknown.
 

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Hello,

may I ask some questions about camshaft selection?

Is it true, that cams like Whipsplash or Thumpr provide to less vacuum to operate power brakes with it?

In one 400cui build on hotrod.com they took a Comp Xtreme Energy 224/230, in another build they took a Thumpr 227/241. Each together with KB240 pistons.

Any thoughts about these or a Lunati cam?

Thanks!
Marian
 

1978 NYB

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Hello,

may I ask some questions about camshaft selection?

Is it true, that cams like Whipsplash or Thumpr provide to less vacuum to operate power brakes with it?

In one 400cui build on hotrod.com they took a Comp Xtreme Energy 224/230, in another build they took a Thumpr 227/241. Each together with KB240 pistons.

Any thoughts about these or a Lunati cam?

Thanks!
Marian

You can always add a vacuum cannister like I did on left fenderwell. I could safely stop after I adjusted driving and stopping techniques. You will get at least one good pump on the brake pedal before the vacuum runs out.

20181013_095944.jpg
 

71Polara383

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Hello,

may I ask some questions about camshaft selection?

Is it true, that cams like Whipsplash or Thumpr provide to less vacuum to operate power brakes with it?

In one 400cui build on hotrod.com they took a Comp Xtreme Energy 224/230, in another build they took a Thumpr 227/241. Each together with KB240 pistons.

Any thoughts about these or a Lunati cam?

Thanks!
Marian

I am thinking of picking this one for a 73 440. Lunati 10230702LK Lunati Voodoo Cam and Lifter Kits | Summit Racing

Seems to have a very nice operating range and will work well with stock components. Also it has a wider lobe seperation angle then the standard 110 that comp cams seems to like to use on their street cams. Wide lobe seperation, less overlap, good vacuum for power brakes and other vacuum operated systems.
 

71Polara383

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Mopar Performance P4529270AE Mopar Performance Purple Camshaft Kits | Summit Racing

The specs on this one is very close to a factory HP "six pack" cam. Alot of guys like the .484 purpleshaft or the bigger .509 but I believe they have tighter lobe seperation which could hurt drive ability, not to mention you are paying double for the Mopar performance stuff.
Unless you are planning on building a lumpy pissed off C body to run right with muscle cars, I wouldn't stray too far from a stockish cam.
 

Ripinator

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Hello,

may I ask some questions about camshaft selection?

Is it true, that cams like Whipsplash or Thumpr provide to less vacuum to operate power brakes with it?

In one 400cui build on hotrod.com they took a Comp Xtreme Energy 224/230, in another build they took a Thumpr 227/241. Each together with KB240 pistons.

Any thoughts about these or a Lunati cam?

Thanks!
Marian

Are you rebuilding a 400 motor, or are you just thinking of upgrading the cam? The stock 400 engines come with a pretty decent cam to begin with, and I don't think you are going to get very much HP / torque improvement by going to a more radical cam. The low compression of the 400 motor is the big thing holding things back. If you are into a full rebuild, and are able to install new pistons that kick the compression ratio up to 9:1 or so, a bigger cam like the aforementioned HP cam (or a little bit better) would work nicely and provide decent vacuum.
 

71Polara383

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Yes, I want to perform a rebuild and add KB240 pistons to rise the compression.
Those will help bump it up, Will still be down in the hole a bit.

For a nice C body that is no slouch the recipe is pretty simple and has been explained probably 12 different times on this forum.

- Reliable Spark/Ignition
- Dialed carb
- Dual plane intake or Stock
- One of the many cam choices similar to HP/Magnum specs or a touch hotter.
- Tighter valve springs that match the cam you select.
- Free flowing dual exhaust. Log manifolds dont look as cool as HPs but really don't make that big of a difference from what I've read over the years.

If you follow these parameters you will be happy with the outcome. I did a similar build on a stock unknown mile steel crank 72 440 for my convertible, Its alot of fun and takes a beating.

What will make the biggest difference in seat of the pants feeling and acceleration is the rear axle gear ratio. I would be going to a 3.23 gear in combination with what I mentioned above, that way long trips on the highway keep the rpms under 3k. If you don't care about the highway and you like to party, throw in 3.91s.

Good luck with your project!

20200816_204347.jpg
 

Ripinator

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Yes, I want to perform a rebuild and add KB240 pistons to rise the compression.

The rebuild of my 440 called for a set of KB hypereutectic pistons too. I purchased this cam and complete kit. It's a dual pattern cam (a little more duration on the exhaust than on the intake) and specs out a little bigger than the Mopar HP cam. The engine has terrific throttle response and excellent vacuum. Unlike Bob, I can stop more than once. . .

img_20170923_105435275-jpg.jpg


Here is a short clip of my first run around the block after installing the rebuilt engine:

 

71Polara383

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The rebuild of my 440 called for a set of KB hypereutectic pistons too. I purchased this cam and complete kit. It's a dual pattern cam (a little more duration on the exhaust than on the intake) and specs out a little bigger than the Mopar HP cam. The engine has terrific throttle response and excellent vacuum. Unlike Bob, I can stop more than once. . .

View attachment 419462

Here is a short clip of my first run around the block after installing the rebuilt engine:



Rip, I've heard from solid people that have had issues/failures with Comp cams/lifters. Thoughts? Comments? Concerns? I have the 274H I plan on using for personal build, also Tim has the same in his 71 New Yorker and has had great success too.
 

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Rip, I've heard from solid people that have had issues/failures with Comp cams/lifters. Thoughts? Comments? Concerns? I have the 274H I plan on using for personal build, also Tim has the same in his 71 New Yorker and has had great success too.

Wyatt: The old gentleman who built my engine mostly builds race engines - almost exclusively. He uses only Comp cams. I had the same concerns as you, but I feel he knows cams better than anyone I know. . . So, I went with his advice and recommendations.
 

71Polara383

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Wyatt: The old gentleman who built my engine mostly builds race engines - almost exclusively. He uses only Comp cams. I had the same concerns as you, but I feel he knows cams better than anyone I know. . . So, I went with his advice and recommendations.

So what you are saying is you went with your engine builders recommendations and are happy with the result?

:lol::thankyou:
 

ayilar

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My thinking for Ming, at Wyatt's suggestion, is to go with the following Lunati kit: "Camshaft and Lifters, Hydraulic Flat Tappet, Advertised Duration 262/268, Lift .475/.494, Mopar Big Block" (CAM K-KIT CHR B V265H12 ; SKU 10230702K). The idea is to get a kit where all the parts are chosen/designed to match. The "Complete Kit includes Camshaft, Lifters, Timing Chain & Gears, Valve Springs, Retainers, Locks, Assembly Lube, Decals, and Instructions."

Jegs lists it as "Mid-level performance street cam with excellent drivability. Exceptional replacement for ''muscle car type cams'' with automatic transmissions. Works well with stock type exhaust manifolds and dual plane intake with mild 4 bbl carb. (...) Improved valve springs and roller rockers are recommended. " Planning to stay with my stock rockers, though, as they should be fine under .500" lift.
 
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