1978 401 Valve Springs Help

[rang-a-stang]

I had my machine shop machine mine for positive retention Viton seals. He said they are vastly superior.

I have seen it done on one of the Motortrend shows (maybe Hot Rod garage?) on a bench, with a special tool that was about $75 (I think?), and considered doing it myself but he was doing my heads anyway and it made more sense from him to do it.

[goldhammer]

Been way to long for me to know what advances in materials or brands available for AMC stuff.

I'll let someone else take that one.

[Wagoneer Taylor]

Don't forget a decent set of seals either

Any recommendations for seals?

[goldhammer]

Don't forget a decent set of seals either

[Wagoneer Taylor]

Well Hey that makes me feel much better!

Did you buy retainers and locks as well?
744-16 and 603-16.

[rang-a-stang]

Those are the springs I am running on mine.

[Wagoneer Taylor]

After talking with Comp Cams, they recommended PN 940-16

Max Lift:0.64
Installed Height:1.9
Coil Bind Height:1.2
O.D. of Outer:1.464
I.D. of Outer:1.07
Spring Style:Single
Spring Rate:241
Seat Pressure:93
Damper:Yes

This seems to match up with what you guys have listed above. Just need to check OD and ID specs.

[Wagoneer Taylor]

This is a really good How-to vid for you.
https://www.youtube.com/watch?v=oFX_Xq9WHTI

[SC/397]

This is a really good How-to vid for you.
https://www.youtube.com/watch?v=oFX_Xq9WHTI

[Wagoneer Taylor]

I dont know whether to laugh hysterically or

I am going with laugh!

[rang-a-stang]

[Wagoneer Taylor]

Thanks guys, this is helping me narrow it down at least.

[SC/397]

Those specs look about right. 1.800" installed height and around 100# on the seat. I think the lighter ones may have been around 80# on the seat.

[Cliff]

I had mentioned that my Chilton's only included the 401 up to 1974, but I was wrong - it goes to 1976. Here are the specs:

outer spring test pressure 223 lbs @ 1.35"
spring installed height 1-13/16"

There is a separate spec for police engines:

outer spring test pressure
intake 270 lbs @ 1.38"
exhaust 270 lbs @ 1.19"

The test pressure specs for 1976 360 CID are 213 lbs instead of 223, same height

[Wagoneer Taylor]

I guess the main reasons I eliminate the rotocaps is because the early engines didn't have them and because it is harder to find the shorter springs.
Also, there is less of a problem with coil bind if you are using a slightly higher lift cam.

So the springs you sent in the link are longer then stock?
The problem I am having is I dont even know what size I should have in the first place?
I am running a stock cam.