bulldogchesty
Senior Member
It's not the thermostat!!!
Aluminum Cylinder Heads
- Thread starter 1978 NYB
- Start date
commando1
Old Man with a Hat
That was supposed to be a sarcastic question...
Ripinator
Old Man with a Hat
And the war between headers vs cast iron manifolds CONTINUES.
Fixed. . .
70bigblockdodge
Old Man with a Hat
I would not say worthless
This will not end this debate but adds more ammo to either side of this debate.
Bob I am not saying to put headers on your car but you do gain more than just at 6000 rpm
Landyacht
Active Member
monaco75
Senior Member
Idk... Everybody always complains about headaches that come with headers.
These tri-y's have been on the Newport for the last 10 years. Even after been neglected by that kid, and out sitting in the swamp the last few years, still no leaks. Can see the exhaust system showing it's age now, and I'd like to pull the headers to get ceramic coated, but have had no troubles out of em. Also no ground clearence issues.
Maybe I got lucky? If I had the $$ at the time, those hookers would have been on the blumo. But thats just me.
I understand not going with em on a fairly stock motor. But Bob, your going all out with a stroker. Why choke it with manifolds??
These tri-y's have been on the Newport for the last 10 years. Even after been neglected by that kid, and out sitting in the swamp the last few years, still no leaks. Can see the exhaust system showing it's age now, and I'd like to pull the headers to get ceramic coated, but have had no troubles out of em. Also no ground clearence issues.
Maybe I got lucky? If I had the $$ at the time, those hookers would have been on the blumo. But thats just me.
I understand not going with em on a fairly stock motor. But Bob, your going all out with a stroker. Why choke it with manifolds??
Landyacht
Active Member
If your worried about your headers scraping the ground just get an 8 quart oil pan. the pan will scrape the ground first saving the headers.
has2bmopar
Senior Member
Just want to point out a couple members stated that the Stealth heads were the only aluminum heads with the straight plugs, however the Mopar heads use the straight plug also. If the morons hadn't jacked the price nearly 200% I would recommend them. I myself would do as 70BBD recommended and do some cleanup on your 452s and get your compression around 9.25 to 9.5:1. If you ran aluminum you should be looking at about a full point higher.
I would also go with a bit larger cam somewhere in the low to mid 220s @ .050"; it will be low end friendly and good down the highway. I assume you are going to use possibly a 3.23 with 235s?
One point I failed to see here was the piston noise that usually accompanies the short skirts on stroker builds and if it was a daily driver accumulating more miles than the average toys we have you would certainly notice a shorter life span. The worse rod ratio also comes into play and the longer stroke you have the worse it gets, which will bump you to longer rods and oil rings over your wrist pins. This isn't going to be a factor for your 451, but the longer strokes mentioned earlier would be a bad call for a low deck cruiser in my opinion. The faster revving you mentioned is due to the lowered reciprocating weight. The stroke on a 451 and a 440 are the same. Another advantage of the RB would be a larger/ longer intake runner.
There was a dyno comparison done on the Mopar 383 vs the Chevy 383 with identical cams, carburetors and both running Edelbrock RPM intakes. The Chevy had the advantage of the swirl port vortec heads and the Mopar 383 ran the open chamber 906s so no help from a quench. The Mopar wasted the bowtie junk badly in HP and torque up to the peak HP which was close at the end of the power range. They attributed the big advantage that the Mopar had was due to the higher deck, giving it a larger intake volume and a better rod ratio.
Here's an example of how short your skirts get with the longer stroke. The left is a 4.5" stroke for a 572 and the other is for a 4.15" stroke 528. Also note how much narrower that your ring lands are with the longer stroke...
I would also go with a bit larger cam somewhere in the low to mid 220s @ .050"; it will be low end friendly and good down the highway. I assume you are going to use possibly a 3.23 with 235s?
One point I failed to see here was the piston noise that usually accompanies the short skirts on stroker builds and if it was a daily driver accumulating more miles than the average toys we have you would certainly notice a shorter life span. The worse rod ratio also comes into play and the longer stroke you have the worse it gets, which will bump you to longer rods and oil rings over your wrist pins. This isn't going to be a factor for your 451, but the longer strokes mentioned earlier would be a bad call for a low deck cruiser in my opinion. The faster revving you mentioned is due to the lowered reciprocating weight. The stroke on a 451 and a 440 are the same. Another advantage of the RB would be a larger/ longer intake runner.
There was a dyno comparison done on the Mopar 383 vs the Chevy 383 with identical cams, carburetors and both running Edelbrock RPM intakes. The Chevy had the advantage of the swirl port vortec heads and the Mopar 383 ran the open chamber 906s so no help from a quench. The Mopar wasted the bowtie junk badly in HP and torque up to the peak HP which was close at the end of the power range. They attributed the big advantage that the Mopar had was due to the higher deck, giving it a larger intake volume and a better rod ratio.
Here's an example of how short your skirts get with the longer stroke. The left is a 4.5" stroke for a 572 and the other is for a 4.15" stroke 528. Also note how much narrower that your ring lands are with the longer stroke...
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70bigblockdodge
Old Man with a Hat
I agree with that but some of it is that the piston pin is centered with performance pistons (that is what's available for stroker engines), stock pistons have a slight offset that along with tall piston makes very quiet.
When I put a Purple Shaft 284/284 cam I bought from Gratiot years ago, uninstalled and new, in my 440 block and checked the degrees on it, that 284 got to be somewhat tame at .050. One other thing was that Max Lift was ONLY for 1 degree of crankshaft rotation. For comparison, a Comp Cams 268 (with the first use of assymetrical lobes) held the valve open for 10 degrees of crank rotation at max lift! The .050 duration was a little less. Agreed, there are many newer cam designs now, so it just depends upon what you want.
A friend put one of the newer Purple Shafts in a 340 Swinger. It sounded very nice and "happy", but he didn't like it and put the original Chrysler cam back in the car. Then, it sounded normal again.
Personally, I think I'd stay with the 451 size. That extra 20 cid might not be felt on the street and would certainly necessitate other upgrades to work right. And cost more to feed.
The car should have a 2.71 rear axle ratio, with 3.21 optional. With the normal tire size diameter, there should be ample torque to fry the tires with a 225 degree @ .050 cam. Check the Lunati listings. They are also advertising assymetrical lobes now, too.
What you can do is retard the cam 4 degrees to bleed off a slight amount of low-end power, only to be regained on the top end. That worked well for a friend with a '69 Super Bee 440 Six Pack, with the stock cam.
Do a dual exhaust with the 2.5" pipe Imperial Mufflers. Not sure about headers as that landscape has changed a lot since I last looked, about 20 years ago.
Check out Hughes Engines and their Chrysler-specific cams and their pistons that make open chambers into closed chambers, operationally. I'd aim more toward 9.5 CR. The modern motors that have the higher compression ratios are using cams which close the intake valve sooner and rely upon higher mechanical compression ratio to make up the difference in power, when compared to the way things used to be. I found an article on that a while back of why it works. Consider too, that you'll need some sort of detonation limiter for anything greater than about 9.5, I suspect. A lower compression ratio run at full mechanical advance (38-40 degrees for B/RB Chrysler engines) is better than a higher compression ratio run with retarded spark (to limit detonation tendencies) . . . per Chrysler.
Remember ONE thing . . . especially for a heavier car . . . don't go to the bottom of the page in the camshaft catalog to find your parts. The ones you really need are higher on the page. Meaning, it's too easy to get too much camshaft for that application, whereas an A-body with 4.30 rear gears would be a different situation.
Better to have an engine with a smaller camshaft (comparatively) that will make rpm and breathe well through a really good exhaust system than a wilder cam that needs higher rpms to work well. The former will get to higher rpms quicker whereas once the latter gets pasts its lower-rpm sag, it'll run strong . . . and last to the finish line.
In pistons, the stock pistons are flat tops, but the 440s are .125" down the hole. That's the 8.2 CR motor with the '72-style heads. The "quench domes" are a neat concept and worthy or consideration.
Remember, too, that most of the people who build the stroker 400s are putting them in hotter B-body and A-body cars suited for drag racing use. You don't want to ruin the demeanor of a NYB with a wilder engine under the hood, with a shaky idle and won't like factory a/c running in the summer, in gear, in traffic. Or cruise quietly on the Interstate at 75mph any worse than they did when new and stock!
By '74, the B/RB stock cams had been enhanced with more duration and more lift to help compensate for the power loss from lower compression ratios. To make "a better air pump". You could do a whole lot worse than to take your stock 400 and put the quench dome pistons in to get about 9.2 CR as those cams get pretty close to the old HP cam that was stock in the Road Runners and such. Add an Edelbrock dual plane and 650 cfm carb, with the high-rise exhaust manifolds and 2.5" pipes. There are some Lunati cams that look to be pretty nice, numbers-wise, and still be good street and highway cams. Consider that with the 2.71 gears, 1000rpm = about 29mph, 3.21 would be about 26mpg in high gear. With the slightly shorter P225/75R-15 size equivalents, 28.5mph and 25.5mph, respectively. Look for cams with an rpm range of 2000-5000rpm, or thereabouts, but NOT with a higher starting point!
Consider, too, that that rpm range can move up a little with a smaller motor (360) and down a little with a larger motor (440). Whereas cam listings usually show a range of displacements for one cam and one power range.
For grins, go to the Comp Cams website and download their camshaft comparing software. Then you can see how various things can affect power curves. Cheap and educational entertainment!
CBODY67
A friend put one of the newer Purple Shafts in a 340 Swinger. It sounded very nice and "happy", but he didn't like it and put the original Chrysler cam back in the car. Then, it sounded normal again.
Personally, I think I'd stay with the 451 size. That extra 20 cid might not be felt on the street and would certainly necessitate other upgrades to work right. And cost more to feed.
The car should have a 2.71 rear axle ratio, with 3.21 optional. With the normal tire size diameter, there should be ample torque to fry the tires with a 225 degree @ .050 cam. Check the Lunati listings. They are also advertising assymetrical lobes now, too.
What you can do is retard the cam 4 degrees to bleed off a slight amount of low-end power, only to be regained on the top end. That worked well for a friend with a '69 Super Bee 440 Six Pack, with the stock cam.
Do a dual exhaust with the 2.5" pipe Imperial Mufflers. Not sure about headers as that landscape has changed a lot since I last looked, about 20 years ago.
Check out Hughes Engines and their Chrysler-specific cams and their pistons that make open chambers into closed chambers, operationally. I'd aim more toward 9.5 CR. The modern motors that have the higher compression ratios are using cams which close the intake valve sooner and rely upon higher mechanical compression ratio to make up the difference in power, when compared to the way things used to be. I found an article on that a while back of why it works. Consider too, that you'll need some sort of detonation limiter for anything greater than about 9.5, I suspect. A lower compression ratio run at full mechanical advance (38-40 degrees for B/RB Chrysler engines) is better than a higher compression ratio run with retarded spark (to limit detonation tendencies) . . . per Chrysler.
Remember ONE thing . . . especially for a heavier car . . . don't go to the bottom of the page in the camshaft catalog to find your parts. The ones you really need are higher on the page. Meaning, it's too easy to get too much camshaft for that application, whereas an A-body with 4.30 rear gears would be a different situation.
Better to have an engine with a smaller camshaft (comparatively) that will make rpm and breathe well through a really good exhaust system than a wilder cam that needs higher rpms to work well. The former will get to higher rpms quicker whereas once the latter gets pasts its lower-rpm sag, it'll run strong . . . and last to the finish line.
In pistons, the stock pistons are flat tops, but the 440s are .125" down the hole. That's the 8.2 CR motor with the '72-style heads. The "quench domes" are a neat concept and worthy or consideration.
Remember, too, that most of the people who build the stroker 400s are putting them in hotter B-body and A-body cars suited for drag racing use. You don't want to ruin the demeanor of a NYB with a wilder engine under the hood, with a shaky idle and won't like factory a/c running in the summer, in gear, in traffic. Or cruise quietly on the Interstate at 75mph any worse than they did when new and stock!
By '74, the B/RB stock cams had been enhanced with more duration and more lift to help compensate for the power loss from lower compression ratios. To make "a better air pump". You could do a whole lot worse than to take your stock 400 and put the quench dome pistons in to get about 9.2 CR as those cams get pretty close to the old HP cam that was stock in the Road Runners and such. Add an Edelbrock dual plane and 650 cfm carb, with the high-rise exhaust manifolds and 2.5" pipes. There are some Lunati cams that look to be pretty nice, numbers-wise, and still be good street and highway cams. Consider that with the 2.71 gears, 1000rpm = about 29mph, 3.21 would be about 26mpg in high gear. With the slightly shorter P225/75R-15 size equivalents, 28.5mph and 25.5mph, respectively. Look for cams with an rpm range of 2000-5000rpm, or thereabouts, but NOT with a higher starting point!
Consider, too, that that rpm range can move up a little with a smaller motor (360) and down a little with a larger motor (440). Whereas cam listings usually show a range of displacements for one cam and one power range.
For grins, go to the Comp Cams website and download their camshaft comparing software. Then you can see how various things can affect power curves. Cheap and educational entertainment!
CBODY67
If you look at many current GM engines, the skirts have been getting shorter and shorter with each new design. The piston noise complaints are basically zilch now, but weren't in the 1990s. The skirts were shortened to obviously help decrease engine friction. It seemed that when coated skirts came to be used in all engines, the piston noise issues vanished. It might be that coated skirts and slightly tighter clearances, helped by syn oils, took the noise out.
As to the Chrysler 383 vs. Chevy 383 comparison . . . in the dirt track world, people sed to spend massive amounts of money to fuse another inch onto the deck surface of a 4.125" bore Chevy block so they could run a longer rod to get 415 cid. This put the piston pin right behind the ring package. If they'd started with a Chrysler B block, with its taller deck, they would have already been there.
The bore/stroke and stroke/rod length ratios of the Chrysler 383 are exactly the same as a Chevy 302. And the Chevy CanAm race motor 430 cid from the later 1960s (which ran better than any other big block Chevy motor!). THAT's the sweet spot for engine ratios! The lower rod ratio, the more the engine relates to torque and lower rpm, but also is much more forgiving of the intake and cylinder head ports. A much stronger "yank" on the mixture that makes up for many suboptimal equipment match-ups. The higher rod ratio needs a better-matched set-up to work, but will make rpm easier. The lower rod ratios are generally for "torque" motors, or motors more oriented toward lower-rpm torque. The 383/400 Chrysler is about 1.89 and the 440 is 1.75. It seems like the Chrysler 360 is a little less than this, but not the 340?
An article in the old "Chrysler Performance" magazine detailed that Chrysler engine designers determined that connecting rods needed a maximum "swing angle" of 15 degrees to not put too much side load on the piston skirts, which consumed power. That swing angle would relate to the later "rod ratio". Chrysler made that determination in the earlier 1950s! Chevrolet discovered it in the later 1960s. Something else is that "long rod" motors usually get more and smoother power as their pistons have increased "dwell time" at TDC before they start to move downward. All kinds of little side issues!
CBODY67
As to the Chrysler 383 vs. Chevy 383 comparison . . . in the dirt track world, people sed to spend massive amounts of money to fuse another inch onto the deck surface of a 4.125" bore Chevy block so they could run a longer rod to get 415 cid. This put the piston pin right behind the ring package. If they'd started with a Chrysler B block, with its taller deck, they would have already been there.
The bore/stroke and stroke/rod length ratios of the Chrysler 383 are exactly the same as a Chevy 302. And the Chevy CanAm race motor 430 cid from the later 1960s (which ran better than any other big block Chevy motor!). THAT's the sweet spot for engine ratios! The lower rod ratio, the more the engine relates to torque and lower rpm, but also is much more forgiving of the intake and cylinder head ports. A much stronger "yank" on the mixture that makes up for many suboptimal equipment match-ups. The higher rod ratio needs a better-matched set-up to work, but will make rpm easier. The lower rod ratios are generally for "torque" motors, or motors more oriented toward lower-rpm torque. The 383/400 Chrysler is about 1.89 and the 440 is 1.75. It seems like the Chrysler 360 is a little less than this, but not the 340?
An article in the old "Chrysler Performance" magazine detailed that Chrysler engine designers determined that connecting rods needed a maximum "swing angle" of 15 degrees to not put too much side load on the piston skirts, which consumed power. That swing angle would relate to the later "rod ratio". Chrysler made that determination in the earlier 1950s! Chevrolet discovered it in the later 1960s. Something else is that "long rod" motors usually get more and smoother power as their pistons have increased "dwell time" at TDC before they start to move downward. All kinds of little side issues!
CBODY67
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