Magnum heads and this cam??

[edbux]

I was looking at a cam with the following specs:

(214 230 duration at 50 on 109 lobe sep with .501 and .522 lift WITH 1.6 rockers)

It's similar to the Hughes Whiplash cams, smaller lift though. Would this lift work with Magnum heads? Valve springs will be changed to accommodate the cam. I was thinking there may be an issue with the valve guides, if not more.

Thanks

 

[71DartGuy]

I'm pretty sure the heads are good to .525 lift. I've heard a lot of different opinions on it though.

 

[dgc333]

That .522 exhaust lift is right at the limit, you will need to check for clearance.

I am running a Comp XE268H (224/230@.050, .509/.512, 110) on my magnum headed 360 and I didn't need to do any guide work.

 

[mullinax95]

I was told by a race engine builder the Magnum heads are junky. They are prone to cracking. I think the heads are used for there small chambers and large valves. Is that correct? What is the chamber size?

 

[AdamR]

The Mag heads tend to crack between the valve seats. However the exhaust port and combustion chambers are better then standard LA stuff.

 

[sharpie]

I was told by a race engine builder the Magnum heads are junky. They are prone to cracking. I think the heads are used for there small chambers and large valves. Is that correct? What is the chamber size?

Magnum heads are by no means junky. There must be a reason people run them on their LA blocks, because to be honest, the shaft-mounted rockers are much more useful if you want to go ultra-porting on the intake runners.

The stock Magnum chamber is 58cc I believe. There is significant retainer-to-guide contact at .53 lift, so that's something to worry about.

All in all though, a good head.

 

[dgc333]

The two sets I have had both had 64cc chambers. I keep hearing about cracks in these heads, neither of mine were. My son was a service manager at a Dodge dealer for a couple of years and he indicated that they never had any issues with cracks. The one weak area which is a non issue if you are going carbed is the plenum cover gasket on the stock magnum intake was prone to failing.

 

[goldduster318]

The two sets I have had both had 64cc chambers. I keep hearing about cracks in these heads, neither of mine were. My son was a service manager at a Dodge dealer for a couple of years and he indicated that they never had any issues with cracks. The one weak area which is a non issue if you are going carbed is the plenum cover gasket on the stock magnum intake was prone to failing.

There are plenty of dodge trucks driving around with the heads being cracked between the valve seats. It must be a superficial crack because I haven't heard of any issues either. I didn't even check and just bolted mine on...no problems!

 

[bobscuda67]

When I built my 340 I bought 2 used stock magnum heads, of which one was craked. Got another one, it was craked. Got another one. It pressure checked ok, but had a hairline crack also. Gave up and bought EQ heads. Stock magnums are prone to cracking.

 

[sharpie]

If I had a better camera, I could show you the cracks of which we speak. I have a pair of stock heads, both with 2+ cracks. Whether or not they'll affect the engine, I don't know. But the cracks are there.

 

[mullinax95]

If I had a better camera, I could show you the cracks of which we speak. I have a pair of stock heads, both with 2+ cracks. Whether or not they'll affect the engine, I don't know. But the cracks are there.

I would be scared to run those... I don't know anyone that wouldn't be.. lol!

 

[edbux]

I got my heads for free and had them checked, they were fine, so I had them rebuilt. Right now the 360 just has a 340 cam in it. I was reading about the Thumpr and Whiplash cams and thought to myself "hmmm....self...those cams sound like a good idea for me..."; but I must have been thinking out loud cause I heard my wife's voice saying NOT AGAIN!!!! She'll never understand but she also doesn't make any comments after the initial. Back on topic, I wonder if I can get a cam ground for the same effect (crazy idle) and keep it under .500 lift.

 

[toolmanmike]

If you want thump, choose a cam with higher duration numbers. You don't need the lift especially at lower rpms. toolmanmike

 

[sharpie]

I would be scared to run those... I don't know anyone that wouldn't be.. lol!

Hah! I don't, I run Pro Topline/RHS heads.

 

[mullinax95]

Hah! I don't, I run Pro Topline/RHS heads.

I hear ya boss man!

I have figured (everyone else has also) that we are limited to three style heads. Stock LA, Magnum, aftermarket iron, and aluminum. Now I for one would hate to go through all the trouble installing the Magnums (which improve compression and flow over stock iron) and always deep in back of mind wondering if they are going to crack or have already cracked. Am I the only one that feels this way?

FACT: Magnums will crack or have been known to crack. I'm not trying to bad mouth the Magnum but I just don't trust them. If I had the money I would go the aluminum route of course. Or ported stock iron, or aftermarket iron.

 

[dgc333]

LA heads crack too! Since the vast majority of the cracks are superficial and cause no problems I just can't get exited about it.