Cure for lazy Magnum...Has anyone built a Magnum for 7k+ revs?
Hey Mr.GTX. What you are experiencing is about normal due to a few facts that one you even stated, it is a good truck engine. I’m not sure if I’d take the stock engine short block to 7K, though it is an interesting thought..... LOL!
First item in upping the lower in an OE engine is its ability to breath in and out only followed by the supporting parts. Now, what does that mean and what parts are we looking at for this air pump? Let’s start at the inside and take note of the camshaft. (I can’t remember what the specs are but) The camshaft is small and good to around that early to mid 4K RPM mark. That’s all that cam really has.
As a cam basic guide line, the replacement cam you choose should then operate in the power band your going to be using. Error on the side of caution for the street.
The supporting parts to that puzzle piece would then be the springs. They will allow the cam to do its job by keeping the valves opening and closing as dictated by the cam. IMO, it is best to gather all the associated parts from the cam grinder. AKA - all Lunati parts, all Comp parts, etc...
Making use of stock or stock modified heads or aftermarket heads is your call. The new trick flow heads offer a bolt on solution to help. They enable the stock Magnum front acc. drive to be used and the use LA intakes. The better it flows, the more power you make.
(OK, that’s a DUH! NO CHIT SHERLOCK! Statement, but an excellent high flowing and high quality head extends the lower making abilities of the cam.)
Which brings us to..... the intake and carb.
Which should also be high quality and high flowing.
Intake manifolds are also like cams, there also given a listed operating RPM band/range. Depending on the cars usage, weight and camshaft being used,
(this is a build dependent & vehicle usage thing. It can get a little dicey)
somewhere around the 3500/4000 rpm range is where a single plane intake would be of great benefit. But also don’t be surprised if you get beat by a dual plane intake.
If the car is not light enough or slightly off on the combo or not taking full advantage of the engines power.... loose you will.
IF your driving this primarily in the street, I would be looking at a RPM or Stealth that is worked on. Port matched and ported up the runners, some plenum work as well. A spacer if needed. And only if needed.
Just because an engine can and does turn 7K doesn’t automatically dictate a single plane intake. You can turn this RPM with a medium size street cam and actually make power there. You may very well turn in a lower ET with a dual plane if the car is on the heavy side.
You asked about the lower end. As a minimum, for north of repeatedly 6500 RPM blasts on a track, a better piston should be employed. You could use a Hyperutecic very well. I personally like a flat top, 2 valve reliefs. You can find that with a KB-107 or the Speed Pro (H116CP) slug pictured below.
Hey Mr.GTX. What you are experiencing is about normal due to a few facts that one you even stated, it is a good truck engine. I’m not sure if I’d take the stock engine short block to 7K, though it is an interesting thought..... LOL!
First item in upping the lower in an OE engine is its ability to breath in and out only followed by the supporting parts. Now, what does that mean and what parts are we looking at for this air pump? Let’s start at the inside and take note of the camshaft. (I can’t remember what the specs are but) The camshaft is small and good to around that early to mid 4K RPM mark. That’s all that cam really has.
As a cam basic guide line, the replacement cam you choose should then operate in the power band your going to be using. Error on the side of caution for the street.
The supporting parts to that puzzle piece would then be the springs. They will allow the cam to do its job by keeping the valves opening and closing as dictated by the cam. IMO, it is best to gather all the associated parts from the cam grinder. AKA - all Lunati parts, all Comp parts, etc...
Making use of stock or stock modified heads or aftermarket heads is your call. The new trick flow heads offer a bolt on solution to help. They enable the stock Magnum front acc. drive to be used and the use LA intakes. The better it flows, the more power you make.
(OK, that’s a DUH! NO CHIT SHERLOCK! Statement, but an excellent high flowing and high quality head extends the lower making abilities of the cam.)
Which brings us to..... the intake and carb.
Which should also be high quality and high flowing.
Intake manifolds are also like cams, there also given a listed operating RPM band/range. Depending on the cars usage, weight and camshaft being used,
(this is a build dependent & vehicle usage thing. It can get a little dicey)
somewhere around the 3500/4000 rpm range is where a single plane intake would be of great benefit. But also don’t be surprised if you get beat by a dual plane intake.
If the car is not light enough or slightly off on the combo or not taking full advantage of the engines power.... loose you will.
IF your driving this primarily in the street, I would be looking at a RPM or Stealth that is worked on. Port matched and ported up the runners, some plenum work as well. A spacer if needed. And only if needed.
Just because an engine can and does turn 7K doesn’t automatically dictate a single plane intake. You can turn this RPM with a medium size street cam and actually make power there. You may very well turn in a lower ET with a dual plane if the car is on the heavy side.
You asked about the lower end. As a minimum, for north of repeatedly 6500 RPM blasts on a track, a better piston should be employed. You could use a Hyperutecic very well. I personally like a flat top, 2 valve reliefs. You can find that with a KB-107 or the Speed Pro (H116CP) slug pictured below.