383 Aluminum Heads and Intake

[NormanPlombe]

I'm considering Edelbrock's top end kit for my '66 383. Their catalog lists their application as 1968-up. Anybody know what's different about the earlier 383's that makes their setup not fit? I thought just about all 383s had the same head geometry....And, yes, I've tried calling/messaging Edelbrock. It's been eternal hold literally for over an hour and no reply to messages. They're apparently in the middle of a move to TN and customer service seems non existent.

I'm wanting to swap to aluminum mostly for weight savings and the convenience of new, complete heads. I've got a blown head gasket and have to take the motor down anyway. I'm not concerned with big horsepower. Any suggestions for other brand's aluminum heads/cam/intake/carb would be appreciated if there's someone who's done this before and had good results.

 

[1978 NYB]

I have these heads on my engine.

 

[1978 NYB]

 

[NormanPlombe]

I had seen that Jegs set and I'm guessing that's what you used. It also added to my confusion as to why the Edelbrock setup excludes 67 and earlier and the Pro Maxx does not. What changed in 68?

 

[Davea Lux]

I had seen that Jegs set and I'm guessing that's what you used. It also added to my confusion as to why the Edelbrock setup excludes 67 and earlier and the Pro Maxx does not. What changed in 68?

The factory went from a closed chamber head to the later open chamber design in '68. The bolt pattern is the same. Whoever did the add probably went with the info in the factory parts books. The open chamber head has a larger dome on the combustion chamber so if you bolt it on to the '67 or older engine, it will drop the compression ratio about a full point. The factory compensated for the larger chamber by running the pistons higher in the bore to keep the comp ratio at about 10-1 on the '68 performance models. If the higher comp ratio is important to you, you could consider having the closed chamber heads reworked and ported to take the 1.72 valves. This would give a good boost in performance at about the same price as the aluminum heads. The aluminum heads have a much higher flow potential potential above 4000 rpms, but to get that you are going to need an after market high performance cam, intake, carb and exhaust to get much increased horsepower out of the better heads.

Dave

 

[LocuMob]

The aluminum heads have a much higher flow potential potential above 4000 rpms, but to get that you are going to need an after market high performance cam, intake, carb and exhaust to get much increased horsepower out of the better heads.

He did say he was considering the top end kit, so he would be getting the cam and intake with it. Carb and exhaust would be an easy solution.

 

[furious70]

One thing to consider is the larger valves in those heads on a stock bore 383.

 

[CBODY67]

The 1968 Road Runner 383/335 had the larger valves in them, too. Same size cyl bore as long as the 383 is a "low-block" B motor. There was one or two years when there was a RB 383 in some Chryslers, along about 1959 or so.

OTHER than the compression ratio drop with the open chamber heads . . . which, if your '66 383 was a factory 4bbl car, might work fine. But if it was a factory 2bbl car, it would drop the CR back into the low 8's, not so good.

ONE main thing is that the aluminum heads usually don't have any exhaust heat to go to the intake manifold for cold weather operation. Which means you'll need a carb with an electric choke (as an Edelbrock AFB or AVS electric-choke carb, or some sort of Holley with the electric choke on it) or learn to use a manual choke.

On the plus side, the alloy heads are lighter and less "heat sink", so the heater will work sooner than it would with iron cyl heads.

On the other hand, for the prices I've seen for those kits, you can upgrde your existing heads to the larger, 1968-size exhaust valves, get hard seats installed at the same time, and be done with it. Then chose a possibly better cam, too. Along with whatever 4bbl intake you might desire . . . looking for deals and sales all the while.

Enjoy!
CBODY67

 

[jcslocum]

Just a data point; I have used the ProMaxx heads on 2-350 chevys and they are very nicely made, with good parts. They needed very little work on the ports to match them up with the intake.

 

[BlueGhost]

If you are running stock exhaust manifolds, you probably want to avoid heads with angled spark plugs. I know 440 source stealth and the 84cc version of Edelbrock e-street heads don't have angled plugs. There is also an 84cc RPM version without angled plugs, not sure of the model number, I think promax has a set also. The 75cc e-street would give a bump in compression, but have angled plugs, so you would likely need a good set of headers to make them work.

You likely can do better than the cam that comes with the Edelbrock top end kit. Something like the small summit cam or the Voodoo 262 cam would be good. You definitely don't want to over-cam a 383 in a heavy vehicle.

 

[Mike66Chryslers]

Big blocks up through 1967 used different hydraulic lifters and pushrods than the 1968+ engines. The early lifters had a smaller-diameter cup than the later lifters, and the cup was a bit further recessed in the lifter, so you needed matching pushrods which were slightly longer and had the smaller ball on one end.

That is why a lot of cam and lifter sets say they are for 1968+ B/RB only. If you're buying a kit that includes lifters and it says for 1968+ only, I am sure that is the reason why. If you are installing 1968+ lifters AND the corresponding pushrods, then it's not an issue.

As @BlueGhost said, do not use heads with angled spark plugs with cast iron exhaust manifolds. I know from experience that they are not compatible with HP exhaust manifolds. You'll be constantly burning #7 plug boot and there isn't a good fix for it.

 

[Mike66Chryslers]

Here are pics of a pre-68 lifter, a 1968+ lifter, and a Comp 1968+ lifter.

 

[CBODY67]

Considering that angle plug heads tended to aim the initial "burn" from the spark plug in a particular direction in the combustion chamber, with modern "fine wire electrode" spark plugs (and their more uniform burn), the angle might not be quite as important as it was in the late 1960s?

Just some thoughts,
CBODY67

 

[496 polara]

The sidewinder heads(If they are still a thing) or 440 source offerings as well. It all depends on what you want out of the build. Even with a stock or small cam cylinder heads that move more air is the way to go IMO.