409 rocker arms

[Red 409 63 impala]

Still working on my valve spring replacement. 63 409 425 hp..found a broken valve spring, doing some checking and the o/d of the springs in the head is 1.550 in...does any one know what the o/d of the springs the are for the stock big port heads is?

 

[Red 409 63 impala]

Forgot to mention it has a hyd cam with Scorpion rocker arms. Not sure of the specs for the cam, as I purchased the car with this engine rebuilt with no run time. Was told the cam had a mild performance grind.

 

[64ss409]

Still working on my valve spring replacement. 63 409 425 hp..found a broken valve spring, doing some checking and the o/d of the springs in the head is 1.550 in...does any one know what the o/d of the springs the are for the stock big port heads is?

GM Heritage shows the ID as 1.070-1.090. No OD specs listed,

 

[boxerdog]

1.550 springs are pretty common but you need to know exactly what the cam is to replace them.

 

[Don Jacks]

The OD on the stock spring is 1.24.

 

[boxerdog]

So someone has already taken care of the spring seats maybe.

 

[427John]

Or maybe not and thats why the spring broke.

 

[boxerdog]

Nothing would surprise me. We have any pics???

 

[Red 409 63 impala]

The valve spring seats look like the were cut for bigger springs, also the seals have a white insert, believe they are Teflon.

 

[55Brodie]

Teflon spring seats are a terrible idea. The material cold flows.

 

[427John]

The valve spring seats look like the were cut for bigger springs, also the seals have a white insert, believe they are Teflon.

So the OD of the flat machined surface of the spring seat is 1.55 or larger? I can't tell from the pic, it looks to me like its still stock size.

 

[Red 409 63 impala]

The 1.55 o/d springs fit in the recess with a little wiggle room.Altough only one spring was cracked I am replacing all of them. I noticed that one other shield starting to split.I received a few tips about not using the oil shields. I noticed the old springs had shined surfaces where the shields were rubbing the springs. This engine only has about 300 miles on it.

 

[Red 409 63 impala]

Is there a replacement valve spring for a 691 head. The same valve spring that came from GM in a stock 425 hp head...if so where is it available.

 

[Murphdog]

The white insert on the ID of the stem seal is teflon. Those are 1 version of a "PC" Perfect Circle, seal. There is also an all teflon version with a metal garter band on the od. I measured spring seat diameters on a 690 & 583 head, both were 1.470 ish. Measured spring od on a 817 head it was 1.2/1.22 ish. Parts book lists 2 different oil shields for LP & HP applications. 3836755 is for LP and parts book states 1-3/8 od. 3795664 is listed for HP, 2-4 bbl applications and parts book states 1-5/8 od which should/would probably fit a 1.450 od spring. So with this info 690 & 583 heads may have 1.450 od springs as standard outfit.
Jeff