Magnum worth it?

[mkayers]

Here's another Mopar newbie question. When I bought my 70 Swinger it came with a 318 from a 68 Coronet sitting in the engine bay. Nothing hooked up etc. I have access to a 318 Magnum from my father in law's Dakota either cheap or free. What are the benefits to the Magnum & should I just do the head swap or the whole engine swap with all the modifications that have to be done that I've read?

 

[Dusterb318]

What are your plans for the car? What are you gonna do with it? If you just want a nice street cruiser I'd swap in the whole magnum engine if it's in good shape. That way you have EFI. I'd ditch the keg barrel intake for the MP M1 intake and maybe up the cam with one of Comps magnum engine cams to help out with some extra power and a set of headers and you're good to go.

 

[mkayers]

Pretty much a street cruiser is what I would use it for. Maybe bump the cam up a bit or something.

 

[needsaresto]

In a word yes!

Roller cam engine block,superior cylinder heads alone are worth it.Take the entire engine.Dont think magnum truck exhaust manifolds will work though..Unless you want to run the fi on the magnum.Not sure how to go about that though.But the earlier the year of magnum the simpler it will be.Any thing 97 and up will be obd(on board diagnostic) and a lot more complex.I think Mopar does have some kind of kit or something.Kinda expensive Im thinkin.

As far as a carb goes,Mopar makes a single and a dual plane.Edelbrock makes an air gap.There may be others Im forgetting.Motor will drop right in and bolt up!A lot simpler to go this way.You can reuse your flex plate and torque convertor.No exhaust crossover in the magnum head,so you need a manual choke or electric or no choke.

No mechanical fuel pump on a magnum(timing cover wont allow for it and the cam snout is too short anyways) so just use an electric.Unless you want to change the cam and timing cover!

Everything else like alt and power steering should bolt up.You may need to swap pulleys to your originals..not sure.Someone else should chime in on that and any other concerns

 

[rumblefish360]

For sure take the whole engine.
From there it might be headers like mentioned above. But otherwise, IMO, it's just an intake swap away for a carbed engine. Though roller cams are alotta bucks, thats all you'll purchase. You have the lifters. Mad power improvments with simple things and a roller cam.

If you want to run the EFI, you'll need to upgrade the fuel system end to end and then mount the computer somewhere.

 

[mkayers]

Thanks guys! The heck with EFI, I don't think I want to mess with that. How much more power can I expect with the Magnum?

 

[needsaresto]

More power?

I'd say it's more like a broader torque curve and more overall power,as compared to an la engine.As far as peak h.p goes the la wins,but how many guys run thier engines at peak h.p rpm all the time?

Across the rpm range IMHO,a magnum is the clear winner.Especially down low.Got to do with far better port velocity and a clear edge in exhaust port flow.Stock out of the box a magnum exhaust will flow 75% of the intake,about 10-15% more than an LA.

Only disadvantage of the mag seems to be that the thin casting is prone to cracks between the valves.Be sure to have them inspected for cracks.Even if they are cracked it's not the end of the world.Can be repaired or replaced.I think new heavy duty castings are less than $300 on ebarf.Much thicker deck solves the cracking.