HEI Conversion 68 Polara

GMPolara

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Hi! I'm considering changing from points ignition to HEI in my 68 Polara. The car has a 383 2bbl. My plan was to get a stock mopar electronic disty and plumb it with an HEI module. But since I have a 383 motor, and this motor was discontinued (71/72) before an electronic distys made thier appearance. What are my options? Will a disty from a 1973+ 400CID work? Trying to keep it affordable. I don't want to race it. I just want it to run smooth and reliably. Plus, I don't want want points.
 
Electronic distributors to fit your 383 are available. Points work well if they are properly maintained. I use a Mallory dual point dist. in my 440 with a Streetfire ignition box by MSD. The Streetfire box says " made in U.S.A. on it.
With that setup the points act as a trigger. With a setup like that you could hide the box and keep your original dist. so it looks stock.
 
Hi! I'm considering changing from points ignition to HEI in my 68 Polara. The car has a 383 2bbl. My plan was to get a stock mopar electronic disty and plumb it with an HEI module. But since I have a 383 motor, and this motor was discontinued (71/72) before an electronic distys made thier appearance. What are my options? Will a disty from a 1973+ 400CID work? Trying to keep it affordable. I don't want to race it. I just want it to run smooth and reliably. Plus, I don't want want points.
Assuming you are talking about the GM HEI, and not something else... The GM HEI module and a Chrysler electronic distributor is a combo that's hard to beat. The HEI is cheap and reliable and gives great
performance.

Some reading: HEI electronic ignition discussion - Slant Six Forum HEI Electronic Ignition Retrofit How-To - Slant Six Forum

If I were to do this, I would buy a rebuilt electronic distributor from @halifaxhops and then you can use a few different mounting solutions for the module. Even just screwing it to the firewall works, but there is a nice little bracket available that just bolts to the distributor.

I'd stay away from the aftermarket clones of the Mopar electronic ignition. They aren't as reliable as the original Mopar conversions.

The other suggestion is to go to a Pertronix conversion. All is contained in the distributor. I have one in one of my cars and it's been very reliable.
 
I looked at the Pertronix but I prefer the cheaper Hei modules. Do either of you no if a 400 disty would fit? Pretty much want to go that direction if it works. I heard the 440 disty is too long
 
I’ve had good luck so far with my Mopar Performance “clone” kit made by Richard E., sold on eBay as the HiRev 7500 kit. One year so far and not a single problem.

Hard to beat $200 out the door and everything included. Some people don’t like them though, so look at your choices and decide what’s best for you.
 
I looked at the Pertronix but I prefer the cheaper Hei modules. Do either of you no if a 400 disty would fit? Pretty much want to go that direction if it works. I heard the 440 disty is too long
The 400 will fit and yes, the 440 distributor's shaft is too long for a 383.
 
The 440 distributor will work IF you use the adapter sleeve which Mopar Perf used to sell.

The 361-383-400 B motor distributors all have the same shaft length and such. The earlier ones used a metal gasket between the distributor mounting flange and the block. Later ones had a stiff rubber o-ring seal which did the same thing. The 440 has a longer shaft to go with the higher deck height of the "RB" block, but the same body dimensions of the B distributor, otherwise.

In the earlier days of Davis Unified Ignition (now "DUI"), his Chrysler units were the base Chrysler housing with the HEI module screwed to the back of the distributor body, with "exposed wiring" to the HEI module. Or the module was on some soft of bracket?

CBODY67
 
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Thx for all the comments. I'm gearing up for an HEI w a disty from a 70s 400. Should work.
 
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Great bracket for the Hei mod remember to use a .3 ohm coil. I like the Petronixs III since it looks stock. Also match the curve in the distributor to the 383
 
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"Dishy 400 piston"? Better check the bore sizes as the 383 piston is 4.25, the 440 piston is 4.32, and the 400 piston is 4.34", as I recall. The 383 blocks, as most back then, were good for .060" over-bore with no issues. going .070" would be highly questionable, at best.

You can get a "quench dome" piston to make the 906 open chamber act more like a '67 and prior closed chamber head as to mixture turbulence. Or somebody's aftermarket head with smaller chambers, or even some '67 440HP heads or equivalent.

As to pistons, you'll probably find more of a "one size fits all" listing that goes back into the early 1960s. DO check the compression height of the pistons you find and compare them to the OEM specs for such! It appears it can be easy to start out with a 10.0CR '66 383 4bbl OEM piston and end up with an 8.0CR motor with many aftermarket pistons. In that mix, too, are the ".020" de-stroke" pistons which were first seen in the middle 1980s to better deal with the fuel octanes of back then and such. So, be careful in what you choose and do the math on CRs of what you find.

Might look for something more in the 1966 383 2bbl with a rated 9.2 CR, which was aimed at 94 Research Octane fuels with lead in them. Or the 1971 383 2bbl piston with 8.7 CR for regular fuel back then.

I ran across an EngineMasters YouTube video of them dynoing a stock 440-3 motor before doing anything to it. It made huge amounts of lower-rpm torque, but "went flat" over about 4000rpm due to its low rated 8.2CR.

Just some thoughts and observations,
CBODY67
 
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Assuming you are talking about the GM HEI, and not something else... The GM HEI module and a Chrysler electronic distributor is a combo that's hard to beat. The HEI is cheap and reliable and gives great
performance.

Some reading: HEI electronic ignition discussion - Slant Six Forum HEI Electronic Ignition Retrofit How-To - Slant Six Forum

If I were to do this, I would buy a rebuilt electronic distributor from @halifaxhops and then you can use a few different mounting solutions for the module. Even just screwing it to the firewall works, but there is a nice little bracket available that just bolts to the distributor.

I'd stay away from the aftermarket clones of the Mopar electronic ignition. They aren't as reliable as the original Mopar conversions.

The other suggestion is to go to a Pertronix conversion. All is contained in the distributor. I have one in one of my cars and it's been very reliable.
You may recall that is exactly what I did in my Polara. Fabricated using a Mopar distributor and GM HEI module. Love it.
 
I put the GM HEI style stand-alone all-in-one aftermarket distributor in my 1987 Chrysler fifth avenue because the 318 lean burn was failing. It cost $75 with very nice "8mm plug wires included" to fit the 318 and it works very well. I recommend it.
GM's coil and innards from the local parts store fit it. It also accepts GM's internal module that retards the timing 7 degrees when cranking to start the motor.

I bought one for my 413 for $75, also with plug wires included. We'll see if it fits past the stock valve cover and a/c compressor. The cap can be clocked on the housing every 90%. That requires a little adjustment with a file.

Don't pull any of the plug wires off the "spark plug" when the engine is running. It hits really hard. All the way to the shoulder.
 
Thx for all the comments. I'm gearing up for an HEI w a disty from a 70s 400. Should work.
I did this at no cost using parts I had. I used an aluminum mounting bracket on the core support. The GM modules are dependable but I have had one or two over the years go bad. But the heat and vibration in the distributor probably attributes to that.
Figuring it should last a long time on that
Core support
 
If you use a stock 4 pin HEI module, use heat sink compound between the module and whatever you mount it too. Not the di electric grease.
 
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If you can only find a 440 distributor, you can swap out the top end of it and install it into your original 383 points distributor. You just have to modify the housing slightly for the wiring grommet. That way, you can keep your original ignition curve and you don't have to find a specific 400 distributor. If you purchase a new distributor from Autozone, you can do the same, if you don't trust the new timing set. The only hard part to doing this is removing the tiny clip deep inside the top of the shaft, under the rotor.

I am the person that makes and sells the HEI conversion mounts. http://www.designed2drive.com
 
They work well bought a bunch from you a few months ago.
 
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