401 - 425 Camshaft Specifications

[65GSConv]

This table was recently posted on V8Buick.com. If authentic and accurate, it should answer a lot of questions folks have of the differences in cams between the 401 and 425 engines in the early to mid 60's. Also includes the specs of the 425 2-4bbl setup.

It looks to me that the 425 cam was the same from 63-65, regardless if it was a 1x4bbl or 2x4bbl, even though the part numbers were different. And it looks like the 401 had the same cam from late 63 thru 66 (again, except the part numbers were different). Has anyone ever put a 63-65 425 cam into their 65/66 401? If yes, was there any noticeable difference?

[WkillGS]

Here's the full article from the GSCA newsletter. It appeared in the 80's or 90's. Considering the source, Dennis Manner, it's as accurate as can be!
One thing to be aware of is that Buick measured the duration at only 0.002" lifter rise.....while most cam manufactures used 0.006" for the advertised specs. End result is the Buick duration numbers are inflated, making it difficult to use for comparisons.
A more common spec for measuring duration is at 0.050". I carefully measured a stock 66 GS 401 cam (used) and came up with:
309*/298* Intake/Exhaust duration at 0.002"
271.5*/266* at 0.006"
209*/208* at 0.050"
Lift was 0.448" Intake, 0.425" Exhaust.
Rocker ratio is 1.6

Doc raved about the '090' cam (last #s in the pn) in his cars. The closer lobe separation, 109* vs 114*, is desired for performance. It's rumored Buick went to the 114* to improve idle quality due to customer complaints about the lumpy idle!
Buick also used the hotter 090 cam in the 66 GS 401 with the Q-jet option

[Jim]

Hi  I just pick up a 65 401  out of a riv gs  took the motor a part the cam  has a part  no. 1362241.      C.  3other side has  f-9.     D.   3.   According to the chart  the no is the same for both the 091 and 090 cams ls there a simple way to tell witch one it is ? Jim

[WkillGS]

That's the casting number. The different cams start with the same casting. It would then be ground differently for the different part numbers. Is anything stamped into the ends? I don't recall if there is a pn or other ID stamped there, it's been a long time since I looked at one.

[Jim]

Hi looking at rebuilding the 65 401 lt block  not much wear so it will be stock bore ,piston  looking  for a nice street cam  with good low-end power  maybe  some porting if I can find templates  make the intake two plane.i have the 400 to go with it 

[Jim]

Hi again also heads what to do  cast iron  guides ?   seals or no seals ,seals just  on the intake ? What brand,   part no.  Have done a couple of bbb's  most of my experience  is in sbc,bbc know I have to learn some  new things with the 401 .jim

[WkillGS]

Hi Jim, I saw your post over on V8. Both Rhett and Joe (GSGTX) have a lot of experience with good street cams. Tom will eventually chime in too, he's our Nailhead guru!
   If the cast iron guides are worn, they can either be replaced or have iron inserts put in. Word is soft bronze inserts are not recommended since they wear due to the Buick's rocker geometry. I'd lean towards having iron sleeves put in, sometimes the factory guides have the hole a bit off center (rumor?) and excessive cutting of the valve seat will be required.... which isn't good.
Valve seals are only needed on the intakes.
Do not let the shop put hardened valve seats in. They may very likely hit water and ruin the head.

[Jim]

Still trying to  sort out what I have  know now it's a 66 401 block heads& intake have red paint under the green so 66 also???but no seals on the intake valves any one have a picture of the right seal for a 66valve stem. Jim