any reason a 78-80 header wouldn't fit a 77?

[villegs]

any reason a 78-80 header wouldn't fit a 77? Didn't the Napz start usage in 80?

[kneesamo]

Round port vs. square port maybe?.

 

The round ports heads came later, maybe starting on the year 1978.

 

Thats my guess.

 

and they did use the L-series in the 720s for abit there.

[datzenmike]

The '80 720 was the last year the 4 cyl. L20B was used. '81 was the first year the next gen NAPS Z22 motor was used.

Up to '78 all L heads used a square exhaust port and matching manifold. '78,'79 and '80 used a round port W-58 head and manifold. Popular wisdom has it that a square manifold will fit over a round port head and work but not so well the other way around.

 

So no I wouldn't try it. The round port header won't properly fit over a larger square port head like on the '77.

[villegs]

Superb, thanks for the info.