K.O. SWINGER
Meeting in the alley since 1976
Pro Comp heads with a competition valve job, six pack with original ta manifold carbs are jetted with 78s on all four corners and 36 in the middle, 4 Speed with the 391 rear ratio
lumpiest cam
- Thread starter rigger3006
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K.O. SWINGER
Meeting in the alley since 1976
it gets old listening to people blame a camshaft for very poor combinations. The sound of a lumpy cam is primarily due to overlap and any serious race cam we'll have a grip of it but stock converters, air conditioners, power steering and other creature features will not work with peaky high overlap camshafts if you throw in a set of Street gears and a heavy car you will have a pig. and the second big mistake that people make is putting one of these camshafts in a 8 or 9.0 compression ratio motor these camshafts rely on high compression to work correctly and to produce maximum power.
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Wasn’t blaming the cam... I was making fun of the poor combination of large cam and stock everything else. I’m well aware of how the engine functions.
Ivoryk3ys78
Well-Known Member
Aren't the Whiplash cams and I would guess some of the others designed to maximize cylinder pressure on low compression engines but still sound radical? I know generally a lopey cam when its a true performance cam is because of overlap. Doesnt it have a lot to do with the intake and exhaust duration staggering on a lot of these?
Wyrmrider
Well-Known Member
voodoo does not belong with the others in post #3
cheap white box low lift long duration race cam will do it with out a lot of machine work
check the elgin or wolverine catalogs
cheap white box low lift long duration race cam will do it with out a lot of machine work
check the elgin or wolverine catalogs
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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yes/yes,and no/sortof,maybe sortof
lemmee fix it for ya;
>Aren't the Whiplash cams, and I would guess some of the others, designed to sound radical, yet attempt to maintain some half-decent cylinder pressure on low compression engines?
answer; yes
>I know, generally, a true performance cam is lopey, because of overlap.
answer; true, but, the overlap exists not by specific design, but as a result of, the long intake and exhaust periods.
>Doesn't it have a lot to do with the intake and exhaust duration, staggering on a lot of these?
answer; If by "it", you mean the idle-lope, sorta yes.
If by "it" you mean the overlap, absolutely yes.
Mostly, with these Whiplash-type cams, the exhaust duration is increased way beyond what would be considered normal, for the amount of the intake duration, which creates extra overlap,and,after re-timing the cam, results in additional lope. Since it is in fact overlap, the potential to make a lil powerbulge at higher rpm does exist..... but the intake duration is not there to support a significant amount.
I understand that this type of cam has an appeal to some, but because the exhaust duration is so large, it steals some of those degrees from the powerstroke, which leaves quite a bit of energy still in the exhaust when the valve opens.... energy that could have been used to drive the rear wheels,and that leads to less potential for good fuel economy.
As for my opinion, if I have to sacrifice fuel-economy, I'd rather actually have the power that should go with that, instead of just sounding like it.
IIRC the 318-Whiplash is around [email protected], which should power peak at maybe 4600, so it's a nice street-sized cam. But the overlap on it is usually found on a cam of a couple to several sizes bigger. So idling in the next lane, I can't tell if it is or is not, a funky cam, until he steps on it; then it's easier to spot as the Rs wind up. This is fine if that's what you want.
As for me, I'd rather pump the compression up, and install a proper 213* cam. Because at low speed/low rpm, pressure is king. Without it you have to band-aid the engine with a hi-stall TC ,and usually, more rear gear. And yes, the whiplash-type cam does lose pressure.
Here's a 318LA example;
Stock, at nominal 8/1 and with the 240/248/111 cam, in at +4, the Ica comes to 48*.
and the 318 Whiplash; has .050-advertised at 213/226/109+5.. Hughes does not publish the .006 or .008 tappet-rise figures so you have to guess. I'll guess the ramps might be ~50 degrees, making that cam to be 262/276/109+5. and then, the Ica becomes 55*, and the pressure loss comes to about 12psi@1000ft elevation.. The 318LA cannot afford that. That 12psi represents a performance loss of 13% at sealevel. So even tho you have moved up from about 196* intake duration to 213*, which should have got you nearly two cam sizes more power, say 25hp, instead, you might get just 22; but that's not the big picture. Which is, that, the loss of pressure means the power is reduced everywhere in the rpm band, compared to what it could be, and specifically, below ~3000 it will get progressively weaker than the stock cam was. Which is a bad thing, especially with a manual trans.
The actual numbers predicted by the Wallace calculator are 139.76(stock), to 127.58(Whiplash), at 1000ft.
With a proper 213 cam and pumped up compression, the psi might be 160, and accompanied by an across the board performance increase below 3500 of about 20%. But with 115* now of power duration, a guy should be able to tune that for great fuel-economy. And sadly, the overlap would be down to 37* versus 51*with the Whiplash, so not much lope goin' on there.
Fun with math.
Well, I guess I should add;
A 318LA
with just 128psi is a sick,disappointing,wet-noodle kindof thing.
at 140psi, altho normal,performance is lackluster
by 160psi, she has really perked up, even with the factory cam. Coupled with a true 213* cam, she could be a lotta fun.
Jus spitballin'
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That's the marketing hook. That's what they "say". But anything with a lot of duration, a late intake valve closing event and tight LSA is not going to build a "lot" of cylinder pressure. Also, there's no way in hell I would run stock springs with a Whiplash cam, even though they advertise that you can.
If you want a cam like "that" the Comp did it right with the Thumpr line. Low lift and lots of duration on a tight LSA. You can run the Comp 901 for small block and 911 for big blocks making springs affordable and they even fit on stock heads requiring no machining. With the Hughes stuff, they all have lifts well over .500 meaning dual springs and possible cylinder head machining, adding yet another cost.
Contrary to what some people around here say, the Thumpr cams perform well.....actual review from people who've USED them back that up. If you're looking for something to sound really nasty and not looking for every bit of power you can get out of something......which is where most street builds are, the Thumpr line might make sense.
"All that" said, you still need to treat them like any other cam with the same duration, overlap and LSA. With higher than stock converters for automatics and lower ratio rear end gears. Just like you'd treat any other camshaft.
Get an old super stock cheater cam. They wrote the book on nasty. Kim
I have a 590 solid flat tappet & lifters, NOS Mopar Performance if interested.
Wyrmrider
Well-Known Member
comp version also uses a .904 mopar lobe- but not as radical lobes as Hughes
inake lobe would be fine if paired with a resonable for performance exhaust and a wider lsa
lots of ways to slice the bolney
not me style
inake lobe would be fine if paired with a resonable for performance exhaust and a wider lsa
lots of ways to slice the bolney
not me style
skrews
Well-Known Member
Yeah that was gonna be my other recommendation. He can still use the 901 sprAng AND that's a real Chrysler cam ground for the .903 lifter.
mopar65
Well-Known Member
Hey your set up sounds pretty close to what I have. Except I am only at 11.1 compression and 1-5/8 headers..for now I dont have a exhaust system yet. Have you raced yours at the track? I haven't got to race my dakota yet.
How would this cam perform in a 408 stroker? I will be getting the typical scat forged rotating assembly with I beams, and icon forged pistons. Target CR is 9.5:1. Might use box stock eddys, haven’t decided on heads yet though.
I do know that I want a solid lifter cam. No more hydraulic for me.
never mind. Not a good match at all for what I have. LOL
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Marcohotrod
Well-Known Member
11.7 at 115 mph with 2.5" edelbrock mufflers
Marcohotrod
Well-Known Member
I am looking for a good dakota for my spare 345
QuickDart360
Well-Known Member
One cam smaller the 296/557 mopar sokid might be good.
jay27
Well-Known Member
I agree with the old Super Stock cam , most cams after a certain point sound similar. Big cams with compression will have a sharper sound however it is not what you were asking. I have a .474 in my garbage truck and it sounds like a .484 , .509 for the most part in my opinion. The post above suggests the .528 solid but I found it to be quite mild as far as idle , again just my observation. I used a superstock roller cam once that idled at 1100 rpm and shook the windows but never had a hydraulic sound like that ever.
I've got a Hughes Solid 264/268 @0.05 in my 408, timing locked at 34°, and the idle is absolutely NASTY....shakes the whole car at traffic lights....lots of fun
. I'll have to upload a video of it at idle some time.
. I'll have to upload a video of it at idle some time.
It’s going in a ‘74 power wagon with a NP435 manual trans. 4.10 gears, but 35” mud boggers.
that is a nice truck you got , i'm looking for a late 70's dodge to put my 426 stroker in love them 70]s pwer wagons
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