'66 383 build, cam question

[Splush]

Some of you may have seen a couple of my previous posts. I bought a '66 Coronet vert this fall. It currently has a small block, 4-spd. The car was originally a 383, 4 spd car. I was able to find a '66 383 to install this winter/spring. This will be my first BB Mopar build. Currently the engine is bone stock, original cast iron intake, exhaust manifolds, etc. I do not have the specifics of the internals as the person I bought it from pulled it from a project car., I did hear it run. I am looking to freshen it up before I install it in the car. I would like to possibly change the intake, headers, electronic ignition and a mild cam. I am looking for a little bit of "thump" and add some torque on the low end as I am running a 3:23. After reading countless posts on FBBO and endless internet and youtube searches I thought that I had decided on a Whiplash Cam from Hughes. Before making a purchase I reached out to Hughes with a couple of questions. The gentleman that replied said that the Whiplash may not be my best option as the earlier 383's are higher compression and I would not be able to run on pump gas. I thanked him for his response and told him what I knew about the engine, nearly nothing, and asked if he had a recommendation. His response was that while I could make a guess, without more information he could not. So, I am asking the hive mind for recommendations. I really hope to get the swap done before {consistent) good weather here in the Bluegrass state. Thanks in advance.

 

[1967coronet]

Low end... dual plane intake like a eddy preformer , thermoquad carb,
26/27" dia rear tire like a 245/60
Good fast curve on the distributor.
Headers like you said .
Cam is the wild card on a 383 with unknown internals.
Careful it could be at or close to zero deck.
It's winter, I would be curious as to what's inside, the intake is coming off so buy a set of head gaskets and do some checking.

 

[BeepBeepRR]

You may want to find out what year the engine is. There is a stamp pad just under the distributor. There you will find a code like D383 It may or may not have an HP stamped as well. On that same area you will find a date. On the bottom of the block on the passenger side of the engine just above the oil pan there will be a number as well. On the driver side there will be a date embossed into the casting. That will give you the casting date of the engine. They had various HP ratings over the years. I think it was 330 or 335 HP.

 

[Jerry Hall]

Just for information, my 67 383 build was stock bore and stroke, the pistons were 16 thousandths below deck and it was a 4bbl engine from the factory. I believe 66 would be the same for a 4bbl engine. The heads both years would be the 516 casting, 1.60 exhaust valves. I opened it up to the 1.74 exhaust. I installed a Lunati cam, just under 500 lift. This engine should run on premium pump gas. I had @HALIFAXHOPS rebuild and curve the distributor for the cam. I hope this helps you.

 

[HawkRod]

...
Good fast curve on the distributor.
...

.... I had @HALIFAXHOPS rebuild and curve the distributor for the cam. I hope this helps you.

Yes, yes, yes!

So many people spend countless dollars on performance parts, but then ignore one of the biggest keys to a good running car: The distributor curve. You want a good curve, with centrifugal timing coming in around 1000 RPM and all in by about 3000 RPM for good street manners.

 

[Don Frelier]

You may want to find out what year the engine is. There is a stamp pad just under the distributor. There you will find a code like D383 It may or may not have an HP stamped as well. On that same area you will find a date. On the bottom of the block on the passenger side of the engine just above the oil pan there will be a number as well. On the driver side there will be a date embossed into the casting. That will give you the casting date of the engine. They had various HP ratings over the years. I think it was 330 or 335 HP.

A 66 would be a "B" and there was no HP designation.

The stock cam for the 66 did really well but the intake and closed port heads limited the upper RPM power.

If it really is the original short block. Then putting a bunch of good parts on top may be a short term gain. The additional cylinder pressure can raise crankcase pressure and present problems.

You should do a leak down test to see if the valves or rings leak by.

As far as a cam the whiplash has a nasty tone. They are difficult to tune but can produce good results.

You should consider pulling the short block apart and at a minimum honing and installing new rings.

A set of stealth heads would be a good performance adder for the dollars.

 

[pnora]

Some of you may have seen a couple of my previous posts. I bought a '66 Coronet vert this fall. It currently has a small block, 4-spd. The car was originally a 383, 4 spd car. I was able to find a '66 383 to install this winter/spring. This will be my first BB Mopar build. Currently the engine is bone stock, original cast iron intake, exhaust manifolds, etc. I do not have the specifics of the internals as the person I bought it from pulled it from a project car., I did hear it run. I am looking to freshen it up before I install it in the car. I would like to possibly change the intake, headers, electronic ignition and a mild cam. I am looking for a little bit of "thump" and add some torque on the low end as I am running a 3:23. After reading countless posts on FBBO and endless internet and youtube searches I thought that I had decided on a Whiplash Cam from Hughes. Before making a purchase I reached out to Hughes with a couple of questions. The gentleman that replied said that the Whiplash may not be my best option as the earlier 383's are higher compression and I would not be able to run on pump gas. I thanked him for his response and told him what I knew about the engine, nearly nothing, and asked if he had a recommendation. His response was that while I could make a guess, without more information he could not. So, I am asking the hive mind for recommendations. I really hope to get the swap done before {consistent) good weather here in the Bluegrass state. Thanks in advance.

No one can give you an accurate answer. Thats why Hughes was reluctant to answer. Your best interest would be a tear down and find out whats really in there.

 

[Dave6T4]

If you change your stock closed chamber heads to an open chamber style like the late 440 "452" heads, that will drop your compression a full point to live with today's fuel better. As a bonus, these heads have hardened valve seats, better ports, and larger 1.74" exhaust valves. I run them on the 440's in my car. My engines both run the Mopar Performance "Magnum" cam ( replica of the factory RoadRunner/GTX piece ), something like 276/284 duration and .484" lift. I know this cam is pretty old technology, and there are likely more advanced cams out there. The trick would be to keep the duration under 300 degrees, and the lift under .500" to avoid bleeding off lower compression. These cam spec's are old school, not @ . 050" lift. For carb, my choice would be 600/650 Edelbrock with electric choke.

 

[68-500]

If your assuming a stock bottom end. Then a 68-70 magnum cam would be an excellent choice. They had a nice lope in a Roadrunners and Bee’s. Mother Mopar thought it was a good fit.

 

[PRHeads]

My .02 is……

If there is no easily confirmed documentation on exactly what you have, I’d plan on pulling it apart and re-ringing/re-bearing it.
Plan on having the heads looked over.
At least this way you’ll know what you have.

The stock valve springs will only accommodate the mildest of cams.

If they need a bunch of work, then consider new heads, although even Stealths are now $1400.
So if $6-700 will fix up the old heads, that’s still a viable option imo.

After you have assessed what you have, and what you need……. That’s the time to start looking at cam options.

 

[gtxrt]

with 16 thousand in the hole like Jerry Hall said you would have about 9.95 compression. if that is too much for you just put a 39 thousand head gasket on it. that would bring in down to 9.45 over the stock .017 head gasket

 

[68-500]

I personally wouldn’t install the .039 thick head gasket. You open your quench distance up to near .055. That makes quench worthless there by inviting spark knock. If I was determined that lower compression ratio I would enlarge the combustion chamber in the head or install D-dish pistons.

 

[WileERobby]

No one can give you an accurate answer. Thats why Hughes was reluctant to answer. You best interest would be a tear down and find out whats really in there.

Bingo !! How do you go forward, when you don't even know where you're coming from ????

 

[gtxrt]

I personally wouldn’t install the .039 thick head gasket. You open your quench distance up to near .055. That makes quench worthless there by inviting spark knock. If I was determined that lower compression ratio I would enlarge the combustion chamber in the head or install D-dish pistons.

if he is not putting in new pistons and 9.95 is to much what can you do.they have .037 head gaskets .053 they say more than .055 in the hole is bad

 

[gtxrt]

Bingo !! How do you go forward, when you don't even know where you're coming from ????

when he pulls the heads off he will know if it was the factory 4 barrel 9.95 if it is the 2 barrel about 8.8 with the pistons .069 in the hole.

 

[gtxrt]

Bingo !! How do you go forward, when you don't even know where you're coming from ????

i know where am coming from i just don't know where am going. lol

 

[gtxrt]

race tech pistons d-shaped. .006 in the hole

 

[Jerry Hall]

In my opinion 9.95 isn't to much to run on the street. Of course it won't run without detonation on the 87 octane (cat pi$$), but will perform adequately with 93 octane, unless one chooses to radical a cam, and doesn't tune it properly. I will have no worries as I mix my fuel or run straight 100 octane low lead.

 

[dvw]

View attachment 1594729
In my opinion 9.95 isn't to much to run on the street. Of course it won't run without detonation on the 87 octane (cat pi$$), but will perform adequately with 93 octane, unless one chooses to radical a cam, and doesn't tune it properly. I will have no worries as I mix my fuel or run straight 100 octane low lead.

Depends on the cam. I built a 1970 375/440 for freind. All the open areas of the chambers were eqaulized. KB quench dome pistons were fitted to .045" quench. 9.7-1 measured compression. It runs a very small [email protected]" cam. Stock intake, carb, air filter, exhaust. On 93 it will ping at full timing. It'll take about 33-34 total. As to the 383. Did a hop up for my friends 66 Coronet factory 383 4 barrel. Good condition stock short block. Used home bowl ported 906 heads. I don't remember the cam exactly, but around [email protected]", headers, Performer rpm, Eddy carb, 4.10. It runs pretty well. Full 38 degrees timing with no ping. Street car only.
Doug
Doug

 

[68-500]

When it comes to ignition timing less is more. If an engine only wants say 33* advance, then 33*is the right number. Insisting that the engine needs 36-38 is just pushing against the piston in the wrong direction. Anything we can do to increase combustion chamber efficiency, start with a tight quench, then reducing total advance is a win -win situation. Tight quench is an aid to running what maybe a tighter than accepted compression ratio. Sure you can under cam a high compression engine and achieve high cylinder pressures that produce pinging. But why build such an engine and then hamstring it with a tiny cam?
For instance late Ford 302 gt heads. Most engines only wanted 28ish degrees advance. The more efficient the combustion chamber the less advance needed.