1966 Chrysler 300, 383 rebuild

[Bryon Mason]

I just became.the proud owner of 66 Chrysler with a 383 4bbl, 727 trans. The engine is in need of a rebuild, it currently runs however the car is not drivable. Previous owner said it was diagnosed as a bad camshaft I want to put a mild build on the engine and put about a 2500 stal in it as well. Just want a little more push off the line to get this sled cruising.My issue is I'm not finding much for the 66 and from what I'm reading these had "bastardized" heads that nobody really wants to deal with. Any advice on this would be appreciated.

 

[Newport 66]

The heads on your 383 are 2406516 castings. They're decent performing heads for your 383 even with a mild cam. There are, of course better flowing heads with bigger ports and valves. It all depends on your goals are for a rebuild. You would be better off with a gearing change. Your '66 most likely has a 2.76 :1 gear ratio. 3.23's would give you better "take-off" and not comprise fuel economy much. Just a thought.

 

[Davea Lux]

Your 383 probably has a 516 head, which was a closed chamber design. It was a good head for a daily driver, but not a good choice for a significant performance build. A lot of this has to do with how much of a performance boost you are looking for and what kind of money you are willing to spend. You could go to a '67 915 or later 906 head and do some moderate port work, install bronze guides, stiffer valve springs and hardened seats. New valves would also be a good idea for a performance build. That will put you at about the same cost as a set of hi flow after market aluminum heads. Another real problem with a performance build on a '66 engine is going to be the low profile intake as it does not flow well and the restrictive stock log manifolds. If you plan to keep those items, a big cam, high stall convertor and a set of performance heads are not going to help all that much. You will need at a minimum a good after market intake and either headers or a later set of HP exhaust manifolds and the appropriate larger diameter exhaust tubing. I suggest you dome some heavy thinking as to what your budget is going to be and how much extra horse power you want. As noted above, a set of 3.23 gears is also a must for a performance build if you plan to do mixed highway and city driving.

Dave

 

[bigmoparjeff]

More potential bad news:

Before ordering a converter you need to verify the year of the transmission. Chrysler changed the front pump and converter in '67. Years ago you couldn't get a performance converter for the '66 and down transmission. You had to change to the newer style pump if you wanted anything other than the stock converter. I have no idea if anyone now makes a higher stall for the '66. I did a quick ebay check, and many of the 727 converters are listed as 1967-up. Some say they fit all years, but I would be suspicious of those listings, and would be sure to verify fit before buying.

Looking beyond the mechanical issues, it appears that you got a nice, solid car to work with.

Jeff

 

[Gerald Morris]

I'll buy it if you get bored. I LIKE '66 C-bodies! Yes, the tranny is a transitional build, so you had best stick with it and the engine it was paired with, as I found out. If you drop a newer engine in, get a newer trans then. The 516 heads give you good high compression, which folks don't appreciate much in this era of 86 octane Coleman gas at the pump.....

Am finishing up a dual exhaust install on mine. Again, buz me if you get bored with that. I want another. Looks like you did well for yourself....

 

[Bryon Mason]

The heads on your 383 are 2406516 castings. They're decent performing heads for your 383 even with a mild cam. There are, of course better flowing heads with bigger ports and valves. It all depends on your goals are for a rebuild. You would be better off with a gearing change. Your '66 most likely has a 2.76 :1 gear ratio. 3.23's would give you better "take-off" and not comprise fuel economy much. Just a thought.

Sorry forgot to mention, the rear end is actually the SG with 3.23 gears

 

[Bryon Mason]

Thanks for the advice so far everyone, just to clarify my intent is just to make a solid cruiser out of this car, keep it as original as possible, update the wheels, a little more power out of the engine just to help get it rolling quicker and run dual exhaust because who doesn't love the sound of a good idle and rumbling exhaust! Heres a couple more pics of the inside. Just needs some minor interior repairs. I'm pretty excited about this car!

 

[Mike66Chryslers]

Don't go crazy with a high-stall torque converter. As others have said, 1966 727 input shaft has 19 splines, which is different from 1967+ 727s, so an off-the-shelf aftermarket converter won't work.

For a fun street car, look for a cam which says it has a power band that starts at idle or just above idle. Cams described as good for towing or RVs would be a good choice. You want to generate power in the RPM range where you'll actually use the engine most of the time.

As mentioned already, the 516 heads don't have a good-flowing port design compared to the 915, 906 and later heads. They also only have 1.6" intake exhaust valves, not the larger 1.75" valves of later big block heads. They're still ok if you're trying to build low-end torque. However, those heads also do not have hardened exhaust valve seats, so you'll eventually wind up with burned valves if the engine doesn't have them already.

If you do get later heads or aftermarket aluminum heads, do not get them ported. Going big on the ports helps peak horsepower but will hurt the throttle response and low-end torque which you want. Similarly, dual exhaust is a good addition, but don't go over 2.5" diameter pipes.

 

[Mike66Chryslers]

Oh yeah, that's a really nice looking 300, congrats on the purchase and welcome to FCBO.

 

[413]

For a street cruiser the 516 heads are just fine. They have 2.08 intake valves and 1.60 exhaust valves.

Keep the cam on the smaller side, too big and you are giving up bottom end which is what makes good throttle response and driving from a standing stop.

Glad to hear you have 3.23 gears.

 

[PH27L7]

You can make the 516's run quite well with a little work. I put in big valves & had a buddy do some bowl work. Made a quench motor using 440 rods & off the shelf Diamond flat top pistons meant for that purpose. Amazingly strong for a 383 & very tame. With the quench it is more efficient & requires a lot less timing than open chamber heads.

 

[Ripinator]

For a street cruiser the 516 heads are just fine. They have 2.08 intake valves and 1.60 exhaust valves.

Keep the cam on the smaller side, too big and you are giving up bottom end which is what makes good throttle response and driving from a standing stop.

Glad to hear you have 3.23 gears.

One more thing: Make sure you get the complete cam kit: cam, lifters, push rods and springs. Also a cam with a dual pattern profile will help compensate a little for the smaller exhaust valves. Here is the setup I'm running in my '66 300:

Xtreme Energy 218/224 Hydraulic Flat Cam for Chrysler 383-440

 

[Bryon Mason]

One more thing: Make sure you get the complete cam kit: cam, lifters, push rods and springs. Also a cam with a dual pattern profile will help compensate a little for the smaller exhaust valves. Here is the setup I'm running in my '66 300:

Xtreme Energy 218/224 Hydraulic Flat Cam for Chrysler 383-440

View attachment 393461

You dont by chance have video of it running do you? I'd love to hear what it sounds like.

 

[Gerald Morris]

One more thing: Make sure you get the complete cam kit: cam, lifters, push rods and springs. Also a cam with a dual pattern profile will help compensate a little for the smaller exhaust valves. Here is the setup I'm running in my '66 300:

Xtreme Energy 218/224 Hydraulic Flat Cam for Chrysler 383-440

View attachment 393461

I have an RV cam in my 400, IFF it hasn't been flattened by abuse. I LOVE high compression engines set to deliver big torque at the bottom end with a tight rear end behind them. I recall my 1st 351C actually had closed quench heads, and would surprise the **** out of many a Transam/Camaro and even Duster drivers with such a setup. I concur strongly that one should obtain lifters, valve springs, push rods et cetera in conformity to the cam one selects.

 

[Ripinator]

You dont by chance have video of it running do you? I'd love to hear what it sounds like.

Here is a short video:

 

[CBODY67]

For the '66 300s, the 383 4bbl was standard, which came with a standard 3.23 axle ratio. SureGrip was optiona.. 2.76 was the 383 2bbl standard ratio, but was optional on the 383 4bbl. FWIW

As teh 383 4bbl is rated at 10.0CR, adding the 906 open chamber heads will lower the CR so that 93 pump octane works well, plus gets the better ports and larger exhaust valves. Something you can plan on later. For lower end torque, you usually want smaller hi-velocity ports for good cylinder filling at the lower rpms, NOT hogged-out ports that only flow well at .500" lift.

For a bit better cam, the '67 383 4bbl-spec cam was 256/260 degrees advertised duration, with the '68 "Road Runner" and '67 GTX cam being 268/284 degrees advertised duration. with about .450"+ lift. Which would equate to something in the 215 degrees @ .050" lift range.

I suspect the current Edelbrock PERFORMER intake for the 383 would be an updated version of the Edelbrock hi-rise aluminum intake which Chrysler sold in the old Direct Connetion parts program . . . WITH a factory Chrysler part number which made it legal for NHRA stock class drag racing, back then. A pahlpir of the B/RB HP exhaust manifolds would round out the combination, with a larger diameter dual exhaust with stock-type high-flow (possibly Steet Hemi spec mufflers). End result, an engine with good off-idle throttle response (NOT WOT off-idle, but once rolling) that will get decent fuel economy on highway trips AND be nice to drive, in general. A milder cam will help lower rpm response but the good dual exhaust will make it "a torque motor that will RPM".

On top of that low-height 4bbl intake is a 550cfm carb, so a better intake manifold with a more modern AFB or AVS2 would help a bit there.

IN the current state of affairs, even with the 383 and the good TorqueFlite, almost every 4cyl you mifght encounter can beat the car from a red light. Due to their lighter weight AND a "jillion-speed" automatic that has a 4.50 low gear in the trans. BUT the 383 with the 3.23 (or even a 2.76 has enough low-rpm torque to lay rubber, at least until the tires get traction, which is still respectable. The SG will make that a bit harder, though, as will wider rear tires!

So, get a stock-replacement cam for a '67+ 383 4bbl, with a new timing chain, plus a few maintenance issues on the engine (there are probably a few anyway). Get it running reliably, with new rubber fuel line sections from the fuel tank forward. And DRIVE it to learn more about how it feels. A set of good HD shocks is also good, along with new brake shoes, for good measure.

The car has definite possibilities! The interior is pretty nice, appearing to have been re-done previously, BUT sewn in teh factory pattern. So a little spiffing there would be good, but not necessary until later.

Enjoy!
CBODY67

 

[Ross Wooldridge]

Nothing wrong with 516 heads... here's my 440, stock, points ignition, 3:23 SG rear...



Just allow it to breathe, and have fun.

 

[RagTop66]

Thanks for the advice so far everyone, just to clarify my intent is just to make a solid cruiser out of this car, keep it as original as possible, update the wheels, a little more power out of the engine just to help get it rolling quicker and run dual exhaust because who doesn't love the sound of a good idle and rumbling exhaust! Heres a couple more pics of the inside. Just needs some minor interior repairs. I'm pretty excited about this car!View attachment 393368 View attachment 393369

That’s a sweet ride! Not to be biased, but I’m extremely happy with the 15” magnum 500’s I put on my ‘66 Polara. The 15s fill up the wheel well nicely and while not OE, I think they look right on the car and give you lots of size options.

 

[70bigblockdodge]

Just use a cam with more exhaust duration and you will be fine. The stock converter will be fine as long as you don't go stupid with the cam, then your on your own.

 

[Bryon Mason]

That’s a sweet ride! Not to be biased, but I’m extremely happy with the 15” magnum 500’s I put on my ‘66 Polara. The 15s fill up the wheel well nicely and while not OE, I think they look right on the car and give you lots of size options.

View attachment 393607

Nice!! I was eyeballing something like this