273 to 340 swap

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daves66valiant

daves66valiant

68 Dart 340/727:66 Signet Vert 340/5spd: 68 D100
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Getting ready to pull the old 273 and send the convertible to the paint and body shop for a fresh coat of B7 inside and out. I have a built 340 in the garage with no accessories. I was wondering what I could reuse from my 273? Alternator, regulator, power steering pump and brackets, distributor, radiator metal shroud, etc?

You guys have any good recommendations on what other things need to be replaced/swapped while the engine is out.

Convertible Resto 1.jpg
 
The 273 probably has the early water pump with bottom hose going to the driver side of radiator. The 340 probably has the water pump with passenger side hose exit. If this is the case I'm thinking the pulleys and brackets might not work on the 340 or at least not with out modification or shims. based on my 273 to 340 swap.

I used the pulleys & brackets that came with the 340 engine
 
I used 273 stuff when I built my motor so that all the pulleys and stuff would work. I'm running the newer timing cover, but I'm using a factory little plate that bolts to the two bottom bolt holes of the water pump for the time tab and the 273 harmonic balancer that matched.


What year is your 273? Does it having the little timing mark that bolts to the bottom of the water pump like mine? If it does then I would think that the easiest way to do this would be to use front cover that's already on the 340 and get it up on number one and zero it out on the timing mark. Bolt the 272 timing mark and water pump on and remark the balancer to match the bolt on timing tab so that both are reading zero. Then you can use the pulleys, alternator bracket, power steering pump and the radiator will even work.
 
The 340 has a new water pump that appears to be OEM. The 340 was already dynoed, tuned and broken in. Seems like what you are saying is that the water pump would make all the diference as far as using the power steering and alternator brackets from the 273.
 
Thats correct

The old water pump on your 340 will probably block the timing marks

I have never tried installing the old pump to 340 timing chain cover to see if it works but if you can resolve the timing mark issues that may be the way to go.
 
I went out tonight and looked at both engines and both water pumps. It appears that the alternator bracket will work without much problem. The power steering pump bracket may still be a problem as far as bolting onto the 340 water pump and getting good tension on the belt. The time marks are on the driver's and the water pump inlet is on the pass side for the 340. And it is opposite for the 273 water pump as zhandfull stated.

Moparlee's ideas seems like it will work fine by just adding the 273 timing tab and zeroing the 340 mark and then placing another mark on the balancer where the 273 tab is zeroed. Seems very doable but maybe the power steeering pump will block the view of the timing notches on the 340 block, while the inlet hose may block the 273 timing tab view??? ](*,)

Here are a few pictures. See what you think. Maybe a brand new high performance 273 water pump would help.

340 water pump.jpg


273 alternator bracket.jpg


273 timing mark.jpg


273 timing mark1.jpg


273 timing mark2.jpg


340 timing mark.jpg


273 powersteerig pump.jpg
 
just noticed moparlee said to use the 273 water pump with the 340 cover. makes more sense now. Would hate to buy another water pump since there's one already on the 340. hummm
 
I am running the older style w/p on my 69 B-Cuda w/a 72 340. It is easier to see the timming marks also. I have the bolt on timming bracket on pass side. I do not have that style alternator bracket on mine, I have the bushing type, that I had to fab up. It works good. the only dif in mine is, it had a 69 318 2BBl w/ps,originally. So I did not have the P/S problem. You might have to round up some dif p/s brackets as they might be dif on the 70 and up small blocks.
Milodon makes a high flow old style w/p, which is what I have on mine. I don,t know the P/N ,but Summit sells them, around $60.00-70.00. I have them on both of my cars and will put one on my 66 Dart when I put my other 340 in it. I'll get the P/N when I get home and post it for you, The high flow pumps have a bigger diameter bearing shaft.
If you need a timming tab I have a good stock of them,resonable.

Dave C.
 
The milodon P/N for the old style 69 and pror cast iron pump is 16251
This is a high volume pump. Hope this helps.

Dave C.
 
daves66valiant i like that blue on your valiant. got anymore pics of your car?
 
Why not just find TDC for #1 on the 340 and mark the dampner (for reference make another mark at 2.25" on the circumference =36*) so it can be timed. The power steering bracket should not interfer with getting access for your timing light. M2CsW. All worked okay on mine when I had the 69 340 in it with the same early style dampner and later style water pump.
 
That's good to know. The 340 is a 69'. I looked at all the w/p on Summit but they did not have the extra tabs that the early 66' 273 w/p has. Note on the 2nd picture above on the 273 w/p. it has 3 bolts while the 340 has 2. All of the w/p I saw on Summit are the 2 bolt style. I guess I will have to workout a new bracket if I want to keep the brand new mopar perforance w/p that is already on the 340. I don't think the old w/p on the 273 will handle the new 340 which is well warmed up with go fast goodies and cam, etc. We'll see what I come up with I guess
 
Here are a couple pics from when I first got the car. Has new 15' wheels from Stockton Wheel Company. I repalced the seat covers and carpet. I am actually going with a darker blue on the repaint. Maybe something like moparlee's. I really dig darker blues. I'm trying to get away from the standard B5. Sorry I didn't get better pics before I started taking all the trim off

interior.jpg


all original look.jpg
 
If you use the new style water pump, you will need a new style radiator;
the lower hose is on the wrong side.

I bought a water pump at the local Advance Auto/Parts America;
bought a pump for a 68 340, that has the 8 blades, vs 6.

I am using a 180f Milodon high flow t'stat.
 
I put a 318 in our valiant used old style water pump everything else was a 78 318 there should be no prob using all the pulleys
 
if that motor is a 69 340 if i remember correctly it used the old style water pump and timing cover,,,,only the 340 timing cover had the makes in the cover no tab like a 273,,i have A EARLY 340 cover with the timing marks on the cover im not useing,,

the easiest way is the early stuff or you will be needing a new radiator like soem one replyed,,or you can make a lower hose using a piece of pipe to join 2 together,,,i have been down that raod before,,it just doesnt look factory,,but works,,

i suggest you get a high performance old style pump,,early 340 cover or use the 273 cover with old style hi po pump then all brackets pulleys will work,,and use your same radaiator
 
I had a 273 in my 67 Dart. I am swaping in a 70 340. I used many of the external peices from the 273 because I wanted it to still look original. Used the timing cover and old style water pump from the 273. I also awaped the balancer from the 273 to the 340 -- they both have forged cranks with internal balance. This allows the use of the old pulley set up. Used the 273 valve covers as well -- for the typical onlooker it appears to be a 273 4 barrel. :)

I have not cranked the engine yet, Lord willing, it will be dropped in the car in the morning, but there will still be a few weeks before it is cranked. So I can't really say if it all worked out but I don't know why it wouldn't.

Brian
 
Gordon340 said:
This allows the use of the old pulley set up. Used the 273 valve covers as well.
Brian
Click to expand...

This is what I did also. I like those valve covers. I've been debating to put some aluminum ones on though and selling 273 valve covers.

Lee
 
If you had used the '89-'92 '308 heads(Pre-Magnum 360 Roller), then exhaust wouldn't be a problem, either, but I see you used 'J' heads.
The '308 heads used the smaller exhaust ports like a 273 has, which makes using the stock '64-'66 273 manifolds more feasable.

Sure your exhaust flow won't be terrific (largest pipes that'll fit, along with good mufflers, will help immensely), but on a street car torque is the mover, and there'd be plenty of that.

Mark.
 
I agree with swapping all the old 273 stuff on to the front of the 340 including the timing cover, pulleys waterpump brackets etc. Check the 340 timnig cover to see if its the old style, should have the timing "tab" cast into the cover on the passenger side, if its on the drivers side change the timing cover over to the 273 version - scribe a new timing mark on the 340 vibration damper if need be - and use the 273 timing tab. A lot of the dampers have 90degree index marks already on them making the location of the new timing mark even easier to find. Done! I wouldnt use the 273 damper unless you are sure its the same weight as the 340, the 340's used a thicker (heavier) damper if I remember correctly than the 273 318 versions.

Whats cool is it will look like a 273 but be a 340.....gotta love an extra 67 cubes the better heads etc...
 
barracudadave67 said:
The milodon P/N for the old style 69 and pror cast iron pump is 16251
This is a high volume pump. Hope this helps.

Dave C.
Click to expand...

The Timing Cover on the 340 has the timing marks scribed on the driver's side. I can get around the timing mark issue with the 340 timing cover as far as I can tell. The MP water pump that is on the 340 now is about a half inch thicker than the old stle 273 w/p. Hopefully the Milodon old style hipo w/p has the same dimensions as the 273. If the dampner is thicker as someone posted then I would still have a problem with keeping the 340 timing cover.

Another possibility is to buy 69' 340 brackets and power steering pump if they can be had.
 
Daves66V
I just took some measurement from my 69 B-Cuda w/72 340. You should be able to use the timming cover w/ the t-marks on it no matter.
The orig 69 318 old style w/p is 2 1/8 in thick mesured to the back of the fan pulley, from the little flat on the block on pass side. It's the same on my 69 318. The timming covers I have laying aound are all 2 1/2 in thick, where the w/p bolts on. Just use a tiiming tab.
I will look at my 66 Dart 273 in the morn and see how the p/s is bolted on, and compare it to my B-Cuda.

Dave C.
 
Daves66V
I looked at my 66 Dart 273, p/s installation( which is stock), and it is exactley the same as on my 69 B-Cuda. So if your Valiant is still stock , you will have no problem. Go with the 273 stuff. My 66 Dart has the same kind of alt mounting bracket as in you pic, that might have to be altered.

Good Luck Dave C.
 
barracudadave67 said:
I just took some measurement from my 69 B-Cuda w/72 340. You should be able to use the timming cover w/ the t-marks on it no matter.
Dave C.
Click to expand...


That's what I did also.

Lee
 
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