4/7 swap cams

[79k20350]

Theres only 1 within a hundred miles of my house

 

[79k20350]

saw on Hot Rod TV last week where they swapped in a 4/7 cam with the same specs of the 7/4 except the firing order swap and gained 20 something hp but they didnt say at what rpm.I imagine it was in the upper rpm range since the idea of the cam is to smooth out air flow(thats what was said on the show)

Hp is always gained at upper rpms (in significant amounts) based on how its figured out. You cant ever have more Hp that torque at under 52xx rpms...

Thats why is ths revs out smoother/ longer that wherer yoll see the number gains, unless it bumped up torque in the lower rpms too...

 

[ryan22re]

what is the 4/7 swap cam?

so I see the question was will the cam be a good choice... sorry I dont know much about it as I dont even know what the 4/7 cam is...

It swaps the 4 and 7 cylinder in the firing order. Goes from 18436572 to 18736542. Only thing you have to do is swap plug wire positions on the cap.

Said to reduce crankshaft deflection, rev smoother, balance the intake charge. Generally create more horsepower.

As to the question of price, I guess they have gone down, but it used to be they were $200 more than regular cams. If you were building an engine from scratch, that wasn't an all out race motor, you could save that extra $200 for other upgrades (roller rockers, head porting, better intake, etc) that would get you the extra 10-20 hp the cam would make.

 

[mikey_d05]

Theres only 1 within a hundred miles of my house

There are like 306 in MN and I could throw a rock from my roof and hit three of 'em.

 

[bowtiepower00]

You're not going to notice any difference in a street engine, particularly in a K5. The advantage comes at high engine speeds, and only in a well built and tuned motor. Would Muddinmanny see a slight difference? Perhaps, but I don't think many of the members on here are running a combo as potent as his. If you have a well-built dyno tuned engine running above 6K you may see a couple HP. For the average joe who has a relatively mild engine and who doesn't spin a lot of R's, it's going to be a waste.

The 4/7 swap is more about engine smoothness and intake manifold/ cyl. head flow air pulses than anything. It was originally done by drag racers.

If you're building a 10 second car or something similar, and it is properly tuned, you may see a small benefit. For 99% of all of the other engines out there, it's going to be of no benefit.

Unless you're a racer looking for every last tenth, you're not going to need to mess with it.

 

[sled_dog]

good goal is 10 second car. may take a little spray to get there, but that is alright.