Head differences -77 318 vs -89..?

[Moparbaker]

I've got some stuff laying around & wondering if there's any positive difference on 318 heads from -77 compared to heads from a roller cam -89 engine?
Got both, wonder what ones to work on...

 

[Jadaharabi]

What are the part numbers?

 

[toolmanmike]

What numbers are they? Here's where the numbers are as an example.

 

[Jadaharabi]

That's a 915. Does it have a J cast into it?
What's the number on the other head?

 

[toolmanmike]

That's a 915. Does it have a J cast into it?
What's the number on the other head?

That's just a picture I posted as an example.

 

[Jadaharabi]

More picture of chambers and ports please.

 

[Jadaharabi]

That's just a picture I posted as an example.

lol got me going.

 

[Wyrmrider]

late model heads with the heart shaped chamber take less timing which indicates more efficient
they also have better ports
two versions with various casting numbers
use them if cc match what you want to do

 

[Moparbaker]

Totaly forgot to take pic of numbers... But as I understand from earlier postings the -77 engine can take more power & abuse? & from now/this post I understand that the -89 has better heads? So modifying the -77 for roller cam & using the -89 heads might be the best..?

 

[YY1]

77 is an 8:1 motor

89 is a 9.2:1

Not sure how much is in the head or how much is in the piston.

 

[toolmanmike]

77 is an 8:1 motor

89 is a 9.2:1

Not sure how much is in the head or how much is in the piston.

Probably a bit of both. The 77 should be a open chambered head and the 89 should be closed chambered. Only the numbers will tell the story.

 

[Jadaharabi]

If you have a choice build the 89.

 

[Moparbaker]

Ok, earlier I've been told the older holds up better. I'm not near the engines for about one month so pictures will have to wait. What does open / closed chambers mean?
Thanx for the answers!

 

[toolmanmike]

Depending on the year/engine, open chamber heads are usually lower compression. The closed chamber are higher compression and more efficient. Here's some examples.

 

[Moparbaker]

Alright, now I got it!

 

[MOPAROFFICIAL]

late model heads with the heart shaped chamber take less timing which indicates more efficiency.
There are 4 versions with various casting numbers, 273 #315 closed heart shape, 318 open #675, 318 closed '67 only, 318 closed #302.
use them if cc match what you want to do

I fixed your post.
The 318 intake and exhaust ports all flow roughly the same , none flow better than the next, considering core shift as the variable.
The '67 closed heads have blind exhaust ports so that they flow even with eachother.

 

[Wyrmrider]

adding rollers to the early block is a PITA with varied results
all retrofit HR kits come from the same mfg AFIK
anyone know better

 

[Moparbaker]

So it all kinda sums up to chuck away the -77 engine to who ever need one then...