Magnum Adventure

[sledger46]

The heads arrived yesterday afternoon. They were well packed and this is what they looked like coming out of the box.

Here is the combustion chamber:

Here is the intake side:

Here is the exhaust side:

Here are the Hughes hydrualic roller lifters for the LA block:

With a little luck this weekend, I may be able to get the camshaft degreed and start figuring out push rod lengths. It should be fun with a non-adjustable rocker and hydraulic lifters to figure out pushrod lengths and piston to valve clearance. I guess I need a solid roller lifter to get PTV clearance close. On Ferds you can take the roller lifters apart and flip the insides to create a solid. I don't even want to attempt that with the Hughes lifters. Has any converted a Magnum hydrailic roller lifter to solid? What is involved?

 

[Idaho]

I think this is what women feel like looking at jewelery

 

[LXguy]

I converted some stock magnum roller lifters to solid for pushrod checking purposes.

Its pretty easy. I just pulled mine apart and stacked some washers in it to take up the slack.

I found with my Magnum cam that had been ground on LA blank that i needed pushrods approximately .040 longer than stock.

Of course your lifters are a ton taller than stock, so you'll mostly be going back the other way.

 

[sledger46]

My back has been hampering my progress. I am hoping to get the old heads off this week and get the cam degreed. I will have to buy another pushrod length checker, because the one I have will most likely come up short. It will be intresting to see what the LA deck height, thin head gasket, and LA retrofit roller lifters add up to in terms of pushrod length.

How much will I be hurting this combination by running an old LA M1 dual plane intake? Does the LA M1 fit somewhere in between the Edelbrock Performer and the Performer RPM as far as performance?

 

[1wild&crazyguy]

It's a totally diff design, so u really can't compare the two.
The dual plane will pull more on the carb/more vacuum and provide more torque throughout low/mid range rpm while the single plane theorectically should provide more hp at a higher rpm.

 

[sledger46]

The intake I am speaking about is a dual plane design. It is cast in aluminum and has the word Mopar cast on one of the front runners. I have an M1 dual plane off of the Magnum crate motor and when the two intakes are placed side by side they look nearly identical except the intake bolt holes (LA versus Magnum). Here is the intake installed on the LA 360:

You can't see a lot in that picture, but enough to tell it isn't a single plane M1.

 

[sledger46]

Here is a picture of the M1 dual plane intakes. The red one is the LA version. The silver one is the Magnum version.