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Old Aug 21, 2023 | 04:50 PM
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Default Rebuild Cam question

Is this cam and specs better than my factory 427/390 hp cam?


looking for answer before he installs
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Old Aug 21, 2023 | 05:30 PM
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Yes maybe. It's an "old school" single pattern cam with low lift. As always, depends on your goals and what else you're doing to the engine/drivetrain. I run that same cam in my small block 383 in my '32 Ford. It runs fine, a little thumpy at idle...and is easy on parts.

A big block can stand a lot more lift usually without issue at all...and your heads will like it. And a big block typically likes more exhaust duration (split pattern) with OEM heads...but if it's going to be a low RPM deal..then a single pattern can make good torque numbers.

It's all a juggling match.

JIM
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Old Aug 21, 2023 | 06:06 PM
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Yes.
The OEM cam is 214/218 dur @ .050. And HP peaks around 5200 on a 427. It is pretty mild.
Your move up to a 224 dur cam would add almost 700 rpm to the top, and a real strong mid-range. May make peak HP around 5800.
The OEM cam is a 115 Lobe center, dropping to a 110 is going to give you some more rumpity-rump at idle.
IE: the idle will sound 2 steps "bigger".
Idle vac should still be OK, probably around 15" or so.
I really like 224 dur cams for street cams. Think of the L46 350-350 HP. They make around 1 HP per inch, and almost feel stock at low rpm, but have a great streetable mid-range. Pull to near 6000.
Any more duration and the low end TQ really starts to go away. To feed the top end. At 234 dur you start to lose streetability with mild stock gears. You need more gearing, have low vac, etc.etc. Then it starts to feel like a "race cam".
Predicting 425HP at 5800 rpm.

Is that what you are looking for in a cam?
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Old Aug 22, 2023 | 10:33 AM
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Originally Posted by leigh1322
Yes.
The OEM cam is 214/218 dur @ .050. And HP peaks around 5200 on a 427. It is pretty mild.
Your move up to a 224 dur cam would add almost 700 rpm to the top, and a real strong mid-range. May make peak HP around 5800.
The OEM cam is a 115 Lobe center, dropping to a 110 is going to give you some more rumpity-rump at idle.
IE: the idle will sound 2 steps "bigger".
Idle vac should still be OK, probably around 15" or so.
I really like 224 dur cams for street cams. Think of the L46 350-350 HP. They make around 1 HP per inch, and almost feel stock at low rpm, but have a great streetable mid-range. Pull to near 6000.
Any more duration and the low end TQ really starts to go away. To feed the top end. At 234 dur you start to lose streetability with mild stock gears. You need more gearing, have low vac, etc.etc. Then it starts to feel like a "race cam".
Predicting 425HP at 5800 rpm.

Is that what you are looking for in a cam?
I did ask him for more aggressive but not overly aggressive cam, if you mean rear gears car has 3.70 just want to also make sure no loss in vacuum as well
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Old Aug 22, 2023 | 10:50 AM
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Originally Posted by jbradley02
I did ask him for more aggressive but not overly aggressive cam, if you mean rear gears car has 3.70 just want to also make sure no loss in vacuum as well
That cam will serve you well in a 427/390.......and it will make a lot more power.......Leigh is probably spot on about the 425hp number.....
Make sure you remove the inner springs to break in.......
I wrote a whole cam break in check list in a previous thread recently......maybe somebody has a link.....

Jebby
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Old Aug 22, 2023 | 11:12 AM
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Originally Posted by Jebbysan
That cam will serve you well in a 427/390.......and it will make a lot more power.......Leigh is probably spot on about the 425hp number.....
Make sure you remove the inner springs to break in.......
I wrote a whole cam break in check list in a previous thread recently......maybe somebody has a link.....

Jebby
Shouldn’t break in of the cam something the builder would do and I also requested Dyno of the engine after build, but would t mind that link
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Old Aug 22, 2023 | 01:02 PM
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Yes.
3.70 is plenty of gear.
And you should have plenty of vacuum for corvette stuff.
It should run great!

And Jebby is spot on about the break-in procedure the builder needs to run. There are a lot of issues with breaking in flat tappet cams, and the details seem to be lost with younger builders, so unless he has been doing it for like 40 years since when these cars were new, I strongly suggest you get him to follow Jebby's recommendations, including removing half the springs. There are way more steps involved than with a roller cam. Do it right and the cam should live, eliminate just 1 or 2 steps, and you only have a 50-50 chance of it lasting more than 5 minutes. It is much better to err on the side of caution with this.
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Old Aug 22, 2023 | 01:26 PM
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I found it and took a snip for future use......



Jebby
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Old Aug 22, 2023 | 02:32 PM
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My first step after installing one and before installing timing chain...is to drop in the lifters and then spin the cam by hand. Mark each lifter and absolutely verify it rotates (usually on the closing ramp) as you spin the cam. If one of them doesn't..it WILL eat the cam and lifter.

There's a lot of poor machining out there these days.

JIM
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Old Aug 22, 2023 | 02:40 PM
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Originally Posted by 427Hotrod
My first step after installing one and before installing timing chain...is to drop in the lifters and then spin the cam by hand. Mark each lifter and absolutely verify it rotates (usually on the closing ramp) as you spin the cam. If one of them doesn't..it WILL eat the cam and lifter.

There's a lot of poor machining out there these days.

JIM
Amen.....
And it isn't a bad idea to take the lifter straight out of the package and run a straight edge on the heel.....if it is flat....throw it away!

Jebby
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Old Aug 22, 2023 | 03:05 PM
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Originally Posted by leigh1322
Yes.
3.70 is plenty of gear.
And you should have plenty of vacuum for corvette stuff.
It should run great!

And Jebby is spot on about the break-in procedure the builder needs to run. There are a lot of issues with breaking in flat tappet cams, and the details seem to be lost with younger builders, so unless he has been doing it for like 40 years since when these cars were new, I strongly suggest you get him to follow Jebby's recommendations, including removing half the springs. There are way more steps involved than with a roller cam. Do it right and the cam should live, eliminate just 1 or 2 steps, and you only have a 50-50 chance of it lasting more than 5 minutes. It is much better to err on the side of caution with this.
actually he has been doing it for 40 years he works for an Auto Restoration Shop and does their engines as his own business, plus I have seen his articles on his wall as he used to be one of Paul Newmans mechanics back in the day when he was racing
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