273 or 318 or both help

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callmebob

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I'm trying to get my dads 66 Barracuda going (who passed away 15 years ago), but I'm retired and on a fixed income and need the lowest cost possible. The car has a 273 with 2 cracked pistons and no heads. I also have the 318 out of a 87 D150 with a bad crank. I have not checked the pistons yet. But the truck was running good when we pulled the motor. So I am wondering what is a good way to go that will not cost a lot of money. The crank in the 273 is standard and looks like new with no grooves and only 2 or 3 very small pits, the block has a standard bore but has a lip around the top of the cylinders. So I'm asking could I use the 273 crank in the 318 or should I have the 273 bored and buy a rebuild kit and use the 318 heads and intake on it? Or is there another way I can use the two to build one good motor. I know the torque converter hole is different on the 2 different cranks, but I have a new old stock TC still in the box for the 273, my dad bought it before he passed. Any help will be appreciated.
 
IMHO

The cost of 273 rebud would be much more than a 318 rebuild.

A wrecking yard 318 would probably be the cheapest route.

Or even a doner car with a 318
 
you can get a running la or magnum 318 or 360 for less money than fixing either engine that you have.
 
I’d run with the 318. But a junk yard Magnum would be easier and cheaper as well as stronger. You’ll need to get an intake, a chink knock off is fine here and a distributor. I don’t know how well the exhaust manifolds or headers line up. I remember an issue with some people with some headers.

Grab the converter with the Magnum if you can. It’ll require a simple mod to the flex plate for use.

I grabbed a 5.9 out of donor Durango and added the above parts. RPM intake, 750 carb, electronic distributor & Headers were Hooker Super Comps for a B or E body. This is in a ‘79 B body car. It’s an excellent driver.
 
Welcome to the site!
If you want to work with the parts you have, then throw the good 273 crank into the 318 and call it a day. That also addresses the crank flange/convertor issue. Use the rest of the 318 rotating assembly, and all the 273 accessories (timing cover, water pump, pullies, power steering pump & brackets, etc.) Also use the 273 oil pan, pickup and dipstick/tube. Using the 273 manifold on the 318 will allow you to retain the stock Barracuda's throttle and kickdown linkage.
Using all the 273 peripherals on the 318 makes it a virtual bolt-in and it will look perfectly stock.
 
Ok thanks. That's what I was hoping I could do. I read somewhere that if I used the 273 crank I would have to get it balanced for the 318. So do I use the balancer for the 273 or 318 if the are balanced different. I do know I can use all the other parts including the distributor so I wont have to change the wiring. I will go with the Pertronix ignitor 1381a to replace the points and condenser, we did that on a 71 Dart.
 
callmebob said:
Ok thanks. That's what I was hoping I could do. I read somewhere that if I used the 273 crank I would have to get it balanced for the 318. So do I use the balancer for the 273 or 318 if the are balanced different. I do know I can use all the other parts including the distributor so I wont have to change the wiring. I will go with the Pertronix ignitor 1381a to replace the points and condenser, we did that on a 71 Dart.
Click to expand...
I would use the 273 balancer, since it has the timing marks in the correct position for the 273 timing cover (which uses the iron water pump with a driver's side inlet, so you can use your current radiator; which means the timing marks are on the passenger side vs. the 318's driver's sode marks). Balancing the new (different) rotating assembly would be preferable, but if you're basically doing a stockish refresh you could conceivably get away without a balance job, your call on that.
 
273 and 318 are both internally balanced so that shouldn't be an issue. Only issue is what was already brought up, about timing mark location related to the timing cover that is used.
Given the age of the damper I'd send the damper out to either damper doctor or damper dudes and have it rebuilt.

My question is, what became of the 87 d150?
Being from Arkansas it's probably not as rotten as one that's been around here. What was so bad about it that you decided to pirate the engine to (potentially) put in the cuda?
 
The d150 was a farm truck, so it was beat up so bad the only somewhat straight part on it was the top of the cab. It was used to haul hay, fire wood, rocks and any and everything else my dad could thing of. I see running trucks from the 80's around here for $3000 to $4000 that's in fair body shape.
 
If you're gonna scrap that truck cut the roof off at the bottom of the a pillars, the roof was common for rotting out right by the drip rail. And your description of "fair" condition and mine might not be the same
 
There's a 77 with 318 3 speed step side bed that looks descent for $2000 on facebook marketplace in Gravette Ar and a 79 parts truck with a 360 for $700 in Prairie Grove AR
 
HankRearden said:
you can get a running la or magnum 318 or 360 for less money than fixing either engine that you have.
Click to expand...
Around these parts that might not be true, from his description. If the 318 is re-ringable, or maybe doesn't even need rings, I'd drop that 273 crank in and do what it takes to freshen it up a bit and go with it. This of course depends on the actual condition, whether it needs a valve job, and miles etc. Re-ring kits are not expensive.

A magnum is not a drop in. Because of his old converter he'd need to obtain/ make a converter snout bushing for the magnum, as he would if he used the 318 crank
 
IDK guys;
1) the early 273 had lightweight floating-pin rods, 3.63 pistons, and I think a forged crank.
2) the 87 318 has heavier rods, press-fit IIRC, 3.91 pistons, and a big fat cast crank.
IDK if you can swap them without issues.

Ima gonna say that yes both are internally balanced, but balanced to the parts of each engine. I'll bet a box of mattress lint, that the bobweights are different. I have both cranks in my shop, and that 273 crank looks mighty teeny next to the late 318 cast one
 
Years ago i replaced a crank in a rebuilt engine that spun a bearing on break-in. The crank kit was relatively inexpensive and performed without any problems.
I just looked at 318 crank kits and they cost $200-$400.
 
A 273 crank with 318 pistons should be balanced. And it is likely to need Mallory Metal [ $$$$ ]. Might be cheaper to grind the 318 crank if the journals are worn.
 
callmebob said:
Ok thanks. That's what I was hoping I could do. I read somewhere that if I used the 273 crank I would have to get it balanced for the 318. So do I use the balancer for the 273 or 318 if the are balanced different. I do know I can use all the other parts including the distributor so I wont have to change the wiring. I will go with the Pertronix ignitor 1381a to replace the points and condenser, we did that on a 71 Dart.
Click to expand...


Use the balancer that came on the 273 crank from the factory with the 273 crank...
 
Almost forgot to mention something:
When mounting your 273 exhaust manifolds to the later 318 (FYI- your 318 truck manifolds will not fit or work in an early A body), you will notice that the casting around the exhaust ports are slightly different between the two engines- they changed slightly over the years-
Old heads:
1664549439744.png

New heads:
1664549212917.png

This can be an issue for 2 reasons-
1.) The later heads may or may not have an air injection port drilled into the pad (circled). If present, these need to be drilled and tapped to 1/4-20 and have allen head set screws Loctited in to prevent an exhaust leak.
2.) The extended pad of the later heads also causes interference with the downleg of the early 273 exhaust manifold at the #7 port. The extent of this interference can vary, but it will be there.
1664550455448.png

As tempting as it may be, the solution is not to grind away the offending portion of the exhaust port casting- there is a coolant passage just beneath the surface, and if you hit it, the head is scrap. I speak from experience on this. :( Some people claim to have gotten away with it, but I did not.
Sometimes (depending on the amount of interference) you may get away with using a double gasket to space the manifold out from the head to gain the necessary clearance.
More than likely, you may need to use a bare header flange as a spacer between the two surfaces in order to make things happy.
1664551085985.png

This will also require longer studs to be installed in the two end spots to accomodate the additional thickness. Use sealer on these studs, as they are "wet holes"- they extend into a coolant passage.
 
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