Ol' Blue's magnum swap
I've decided to make a bona fide, dedicated post about my upcoming engine swap, for which this forum has already been immensely helpful. not only for information, but in my hunt for parts as well. My main problem though, is that all of the information I needed to know I had to hunt through hundreds of threads to learn. I wanted to try and consolidate as much as I can here in this thread to not only look back on, but possibly help anyone else by saving them some time hunting. A lot of what I am about to post may seem painfully obvious, but I was a complete newbie just a few months ago and so it was painfully obscure to me at the time. So without further Ado, here goes.
I'm working with a 1964 Dodge Dart, two-door hardtop.
Slant 6 engine, 904 auto transmission, push button shift, 7 1/4 rear end.
Engine I'm working with is a 2001 5.9 Magnum. I am unsure as to exactly which vehicle it came from, the oil grommet on the valve cover leads me to think it may have come from a van though. That may be a problem finding an oil cap, we will see.
For starters, if you have a Magnum engine you are stuck with Magnum heads, unless you want to spend some money on machine work to drill out the oil galleys. This is because Magnum engines were redesigned from the LA engines to oil through the push rods rather than the shaft style rocker.
The upside to the Magnum head is that it is to the Mopar small block as the vortec head is to the Chevy, one of the best flowing production heads you can get for that motor.
The downside is, those same production heads are prone to cracking in that little space between the intake and exhaust valve. There are a few beefier aftermarket replacements but that is still extra money.
The Magnum block has a slightly different deck height than the LA engine. It is a little bit lower, and LA pistons will come out the top. You have two options here, use the original Magnum style pistons and deck the block to get the proper quench height, or use LA pistons which will stick up past the deck a little bit. You can then use a .050 head gasket to keep the head a safe distance away and you will wind up with .032 quench height.
The Magnum engine also takes a roller cam, and that is going to cost a little bit more, but it's worth it because of the much higher ramp rate. That gives you more area under the curve for valve lift for a given duration, meaning the power of a bigger cam than the numbers would suggest.
You will need to decide now if you are going to run an electric fuel pump or mechanical, because if you are going to run a mechanical then you need a long snout cam and fuel pump eccentric.
The intake manifold bolts are at a different angle, so you will need a magnum specific intake manifold for it if you are going to carburate it.
There are three different timing covers you can use, and it is at this point you will have to decide before you even start your build whether or not you want to go with the serpentine system that comes with the 5.9, or if you are going with the older V belt design. Unless you are looking for the authentic look of period correct V belts, keeping all of the accessories off of the Magnum donor vehicle will help you immensely. In that case, keep the magnum timing cover and water pump. You will have to have an external electric fuel pump for it.
If you are going to do the V belt set up, you are going to have to get one of two other timing covers. Pre 69, the timing cover has the timing marks on the passenger side and the matching water pump has it's suction on the driver side. Post 69 that is reversed. This will be important because that affects accessory bracket fitment and radiator selection. You cannot mix and match from either side of that date. Pulleys will not line up.
If you are adding a larger radiator 3 cores or larger and hoping to stay with a mechanical fan, you will likely see your fan clutch hit the radiator. A good solution is a fan clutch from a jaguar, and a universal clutch fan. See picture below.
The 5.9 Magnum is an externally balanced engine and has a 5.9 Magnum specific harmonic balancer. If you are doing V belt accessories, you will need to look for an earlier model 5.9 harmonic balancer that is two piece without the pulley permanently attached. Doorman makes it. This will allow you to bolt on the V belt pulley. There may be one hole that does not quite line up with the rest, just use a file to slightly enlarge the hole so the bolt will go in to the balancer.
Reuse the flexplate or flywheel that came with the engine, make sure that the flexplate is weighted so that you can use a neutral balance converter.
1960 to 1967 the torque converter pilot has a smaller shaft than 1968 and up. You will need a bushing to take up the slack.
If you are converting a model with a slant 6, the Transmissions do not share bolt patterns with the V8 and you will need another.
Also, if you plan to keep the push buttons you will need a 64 or 65. If you get a 65, you will need to install a 64 valve body. You can use your slant 6 transmission as a donor.
The first two gears in the slant 6 are lower and you can swap those into the V8 transmission as well to make up for highway gears if you want to run them.
The output shaft on the early transmissions do not have a traditional yoke and U-joint, they have a trunnion. Having a transmission shop swap that out for a more contemporary output shaft will help you find replacement parts more easily in the future.
The lowest price I have found on headers so far has been with Sanderson model DD9. They are shorty headers, and only specced for early A bodies with auto transmission. They are only available with 1.5 inch primaries, but they fit tight with minimal fuss.
Your fuel delivery line will need to be upsized, the one provided with a slant 6 is not going to provide enough fuel for anything over 250 horsepower. You will burn up your electric pumps trying.
The 5.9 block has kept LA style engine mount bosses, but they have been slightly modified. There are two holes up front, and one hole in the back. You can use 318/273 mounts, but you will have to add a half inch spacer on the driver side back bolt to take up some slack, and on the passenger side you will have to weld a new tab on to the front of the motor mount because it only has one bolt hole there.
You will need a 360 LA car style oil pan and pickup. You will also need a new dipstick, the one for the truck pan will not work in the car pan.
You can reuse the Magnum starter, in fact that is required for use with headers because they are so much smaller than the old style.
You will not be able to reuse the Magnum distributor, but an LA distributor will drop right in. There are a few companies making GM style HEI distributors. That is what I am using. They take GM replacement components and a 4 pin ignition module.
The spark plug wire set will be the same 5.9 said you would have bought for the donor vehicle.
If you are reusing the Magnum distributor hold down clamp, you may have to grind a little bit off of the inside where it contacts the shaft of the distributor in order to get the bolt in the hole.
There are two different thicknesses of rubber motor mounts, the thinner one lets the motor sit down a little bit lower for better hood clearance and firewall clearance to distributor, but if your car came with a slant 6 you will want the taller one so your oil pan will clear the center link on your steering.
V8 cars came with thicker torsion bars and one more leaf in the rear springs. That is so the front can carry the extra hundred pounds for the engine, and the rear can handle the extra torque without collapsing the springs.
The 7.25 rear end is marginal past 200 horsepower, seriously consider upgrading. I'm going with a Ford 8.8 personally, sacrilegious I know but they are plentiful, as are aftermarket parts. And they are every bit as strong as the lauded mopar 8.75.
The Slant six throttle linkage is incompatible with V8 carburetor orientation. So is the pedal. Those will need to be swapped out for a V8 pedal and cable linkage. Also, a Mopar specific kickdown cable linkage will be needed.
Stepping over 350 lb of torque, consider subframe connectors.
I've decided to make a bona fide, dedicated post about my upcoming engine swap, for which this forum has already been immensely helpful. not only for information, but in my hunt for parts as well. My main problem though, is that all of the information I needed to know I had to hunt through hundreds of threads to learn. I wanted to try and consolidate as much as I can here in this thread to not only look back on, but possibly help anyone else by saving them some time hunting. A lot of what I am about to post may seem painfully obvious, but I was a complete newbie just a few months ago and so it was painfully obscure to me at the time. So without further Ado, here goes.
I'm working with a 1964 Dodge Dart, two-door hardtop.
Slant 6 engine, 904 auto transmission, push button shift, 7 1/4 rear end.
Engine I'm working with is a 2001 5.9 Magnum. I am unsure as to exactly which vehicle it came from, the oil grommet on the valve cover leads me to think it may have come from a van though. That may be a problem finding an oil cap, we will see.
For starters, if you have a Magnum engine you are stuck with Magnum heads, unless you want to spend some money on machine work to drill out the oil galleys. This is because Magnum engines were redesigned from the LA engines to oil through the push rods rather than the shaft style rocker.
The upside to the Magnum head is that it is to the Mopar small block as the vortec head is to the Chevy, one of the best flowing production heads you can get for that motor.
The downside is, those same production heads are prone to cracking in that little space between the intake and exhaust valve. There are a few beefier aftermarket replacements but that is still extra money.
The Magnum block has a slightly different deck height than the LA engine. It is a little bit lower, and LA pistons will come out the top. You have two options here, use the original Magnum style pistons and deck the block to get the proper quench height, or use LA pistons which will stick up past the deck a little bit. You can then use a .050 head gasket to keep the head a safe distance away and you will wind up with .032 quench height.
The Magnum engine also takes a roller cam, and that is going to cost a little bit more, but it's worth it because of the much higher ramp rate. That gives you more area under the curve for valve lift for a given duration, meaning the power of a bigger cam than the numbers would suggest.
You will need to decide now if you are going to run an electric fuel pump or mechanical, because if you are going to run a mechanical then you need a long snout cam and fuel pump eccentric.
The intake manifold bolts are at a different angle, so you will need a magnum specific intake manifold for it if you are going to carburate it.
There are three different timing covers you can use, and it is at this point you will have to decide before you even start your build whether or not you want to go with the serpentine system that comes with the 5.9, or if you are going with the older V belt design. Unless you are looking for the authentic look of period correct V belts, keeping all of the accessories off of the Magnum donor vehicle will help you immensely. In that case, keep the magnum timing cover and water pump. You will have to have an external electric fuel pump for it.
If you are going to do the V belt set up, you are going to have to get one of two other timing covers. Pre 69, the timing cover has the timing marks on the passenger side and the matching water pump has it's suction on the driver side. Post 69 that is reversed. This will be important because that affects accessory bracket fitment and radiator selection. You cannot mix and match from either side of that date. Pulleys will not line up.
If you are adding a larger radiator 3 cores or larger and hoping to stay with a mechanical fan, you will likely see your fan clutch hit the radiator. A good solution is a fan clutch from a jaguar, and a universal clutch fan. See picture below.
The 5.9 Magnum is an externally balanced engine and has a 5.9 Magnum specific harmonic balancer. If you are doing V belt accessories, you will need to look for an earlier model 5.9 harmonic balancer that is two piece without the pulley permanently attached. Doorman makes it. This will allow you to bolt on the V belt pulley. There may be one hole that does not quite line up with the rest, just use a file to slightly enlarge the hole so the bolt will go in to the balancer.
Reuse the flexplate or flywheel that came with the engine, make sure that the flexplate is weighted so that you can use a neutral balance converter.
1960 to 1967 the torque converter pilot has a smaller shaft than 1968 and up. You will need a bushing to take up the slack.
If you are converting a model with a slant 6, the Transmissions do not share bolt patterns with the V8 and you will need another.
Also, if you plan to keep the push buttons you will need a 64 or 65. If you get a 65, you will need to install a 64 valve body. You can use your slant 6 transmission as a donor.
The first two gears in the slant 6 are lower and you can swap those into the V8 transmission as well to make up for highway gears if you want to run them.
The output shaft on the early transmissions do not have a traditional yoke and U-joint, they have a trunnion. Having a transmission shop swap that out for a more contemporary output shaft will help you find replacement parts more easily in the future.
The lowest price I have found on headers so far has been with Sanderson model DD9. They are shorty headers, and only specced for early A bodies with auto transmission. They are only available with 1.5 inch primaries, but they fit tight with minimal fuss.
Your fuel delivery line will need to be upsized, the one provided with a slant 6 is not going to provide enough fuel for anything over 250 horsepower. You will burn up your electric pumps trying.
The 5.9 block has kept LA style engine mount bosses, but they have been slightly modified. There are two holes up front, and one hole in the back. You can use 318/273 mounts, but you will have to add a half inch spacer on the driver side back bolt to take up some slack, and on the passenger side you will have to weld a new tab on to the front of the motor mount because it only has one bolt hole there.
You will need a 360 LA car style oil pan and pickup. You will also need a new dipstick, the one for the truck pan will not work in the car pan.
You can reuse the Magnum starter, in fact that is required for use with headers because they are so much smaller than the old style.
You will not be able to reuse the Magnum distributor, but an LA distributor will drop right in. There are a few companies making GM style HEI distributors. That is what I am using. They take GM replacement components and a 4 pin ignition module.
The spark plug wire set will be the same 5.9 said you would have bought for the donor vehicle.
If you are reusing the Magnum distributor hold down clamp, you may have to grind a little bit off of the inside where it contacts the shaft of the distributor in order to get the bolt in the hole.
There are two different thicknesses of rubber motor mounts, the thinner one lets the motor sit down a little bit lower for better hood clearance and firewall clearance to distributor, but if your car came with a slant 6 you will want the taller one so your oil pan will clear the center link on your steering.
V8 cars came with thicker torsion bars and one more leaf in the rear springs. That is so the front can carry the extra hundred pounds for the engine, and the rear can handle the extra torque without collapsing the springs.
The 7.25 rear end is marginal past 200 horsepower, seriously consider upgrading. I'm going with a Ford 8.8 personally, sacrilegious I know but they are plentiful, as are aftermarket parts. And they are every bit as strong as the lauded mopar 8.75.
The Slant six throttle linkage is incompatible with V8 carburetor orientation. So is the pedal. Those will need to be swapped out for a V8 pedal and cable linkage. Also, a Mopar specific kickdown cable linkage will be needed.
Stepping over 350 lb of torque, consider subframe connectors.