69 383 heads on a 72 400

[Jason f_19]

Alright bear with me, I'm 19 and don't know a whole lot bout this. This 400 has 383 heads put on but why? Were they trying to compensate for the 400's low compression? And wht is the result as it is now?

 

[pnora]

Your 400 might have 440 heads on it. Who knows what someone was trying to do. What heads do you have.

 

[Jason f_19]

There are the numbers so correct me if I'm wrong. Believe they went to the 383 that was originally in the car

 

[Don Frelier]

They are closed port heads so yes someone swapped the originals to boost up the compression.
Nothing wrong with using them.

 

[RemCharger]

67 and down heads. Small ex valves that can be bored out and replaced with 1.74
Good heads.

 

[33 IMP]

Yep, closed chamber heads, to bump the compression ratio up.

 

[pnora]

2406516 – 1964-1967, 361/383 B/RB

 

[66Satellite47]

A very nice head for moderate performance. Upgrading to the 1.74 exhaust valve is simple and inexpensive. A small amount of pocket port porting produces big power increases. It's a great head for a mid level performance motor. I have done numerous of these with excellent results.

 

[eldubb440]

if both can be fitted with larger exhaust valves, what is the major difference between 516s and small valve 915s?

 

[66Satellite47]

The intake port of the 915 has a different shape which is like the large valve 915. The 915 is pretty much like the 906.
The 516 has a flatter intake floor, much like the later B heads. The 516's may not be the best, but you can them really good for a moderate motor.