6-david-5
Mopars under construction
Hey gang
I want to sanity-check my line of thinking on my 5.9 Magnum engine. I want to install this in my '65 Valiant Convertible, but I'm concerned about using the stock Magnum heads. I'm aware the stock heads have a propensity to crack between the intake & exhaust valve seats, but I have not dealt with that personally. This is what the total of this inquiry is about--what your experiences have been with Magnum heads from a 5.9, and what my best course of action would be with me in the midst of my planning stage.
I did once have a '97 Ram xcab w/a 5.2 & 46re, and drove that truck for 15 years from 84,000 miles up past 280,000! Never had the heads off, and never had overheating problems--just the typical beer-barrel intake manifold problems. For that truck, however, I collected this incredibly-low-mileage 5.9 long block that I dreamed about installing 1 day. This block was sold to me back in 2003 with having reportedly 5 MILES on it!! It was out of a wrecked 2002 3/4-ton truck, and the unpainted iron is all new-looking and bright-gray! You would think this engine was BRAND-NEW, or just a "customer-return" with how unused it looks!
As my old ram truck became fraught with needs, and life was presenting DRASTIC changes, I didn't pursue the swap with my Ram truck, and kept the engine on the stand. The truck has since been sold and is long-gone.
Fast-forward to the most recent couple of years--I now envision this motor in my Valiant. This span of time has provided the luck of hearing about the nightmares guys are having with their 5.9 Magnums in their trucks with the heads developing cracks. As I am gearing up for my '65 Valiant project, I am thinking the following:
Inner Dialog 1). "The original heads from this 5.9 motor are practically new, and they would probably be no problem for as long as I have this car--even as I contemplate keeping it indefinitely. I should go to work on the valve pockets & do some light porting, and reassemble these heads and get them ready for use."
Dialog 2). Although this 5.9 is going to be in a spirited cruiser with nothing-but-street-miles, a carb, and a reasonably mild cam (most likely less than .500" lift) with the stock valve gear, the "case studies" are out there on these heads, and preparing them for use for this car COULD have me ripping this thing back apart sometime in the future--maybe even LATER into the future when I might be less-inclined to rip this thing apart. Worse, if money was an issue later, I may be addressing issues with cylinder heads, which may or may not lay the car up for who-knows-how-long due to cost/time/life. I should probably find a buyer for these original head castings, and cap this build off with a set of EQ heads.
Dialog 2.1)............. HOWEVER, with a fully-prepped set of EQ heads, it is approaching aluminum head money! But I really wouldn't need, say, a set of Edelbrock RPM's! It would just be nice to take some weight off the front while I'm spending that kind of money. I WISH THEY MADE E-STREET heads for the Magnum!
I don't know what the cause of the cracking is on OE Magnum heads, or if them being on a car would improve their longevity. I have heard guys have driven on them cracked and they never knew! I'm looking to clear my perspective so that I can get past this rut!
Your experiences with this quandary would be greatly appreciated!
David
I want to sanity-check my line of thinking on my 5.9 Magnum engine. I want to install this in my '65 Valiant Convertible, but I'm concerned about using the stock Magnum heads. I'm aware the stock heads have a propensity to crack between the intake & exhaust valve seats, but I have not dealt with that personally. This is what the total of this inquiry is about--what your experiences have been with Magnum heads from a 5.9, and what my best course of action would be with me in the midst of my planning stage.
I did once have a '97 Ram xcab w/a 5.2 & 46re, and drove that truck for 15 years from 84,000 miles up past 280,000! Never had the heads off, and never had overheating problems--just the typical beer-barrel intake manifold problems. For that truck, however, I collected this incredibly-low-mileage 5.9 long block that I dreamed about installing 1 day. This block was sold to me back in 2003 with having reportedly 5 MILES on it!! It was out of a wrecked 2002 3/4-ton truck, and the unpainted iron is all new-looking and bright-gray! You would think this engine was BRAND-NEW, or just a "customer-return" with how unused it looks!
As my old ram truck became fraught with needs, and life was presenting DRASTIC changes, I didn't pursue the swap with my Ram truck, and kept the engine on the stand. The truck has since been sold and is long-gone.
Fast-forward to the most recent couple of years--I now envision this motor in my Valiant. This span of time has provided the luck of hearing about the nightmares guys are having with their 5.9 Magnums in their trucks with the heads developing cracks. As I am gearing up for my '65 Valiant project, I am thinking the following:
Inner Dialog 1). "The original heads from this 5.9 motor are practically new, and they would probably be no problem for as long as I have this car--even as I contemplate keeping it indefinitely. I should go to work on the valve pockets & do some light porting, and reassemble these heads and get them ready for use."
Dialog 2). Although this 5.9 is going to be in a spirited cruiser with nothing-but-street-miles, a carb, and a reasonably mild cam (most likely less than .500" lift) with the stock valve gear, the "case studies" are out there on these heads, and preparing them for use for this car COULD have me ripping this thing back apart sometime in the future--maybe even LATER into the future when I might be less-inclined to rip this thing apart. Worse, if money was an issue later, I may be addressing issues with cylinder heads, which may or may not lay the car up for who-knows-how-long due to cost/time/life. I should probably find a buyer for these original head castings, and cap this build off with a set of EQ heads.
Dialog 2.1)............. HOWEVER, with a fully-prepped set of EQ heads, it is approaching aluminum head money! But I really wouldn't need, say, a set of Edelbrock RPM's! It would just be nice to take some weight off the front while I'm spending that kind of money. I WISH THEY MADE E-STREET heads for the Magnum!
I don't know what the cause of the cracking is on OE Magnum heads, or if them being on a car would improve their longevity. I have heard guys have driven on them cracked and they never knew! I'm looking to clear my perspective so that I can get past this rut!
Your experiences with this quandary would be greatly appreciated!
David
