59-61 401 CAM? I want to print some info I got out of the December 2001 issue of Car Craft. "You might be surprised to learn that '59-'61 401's were fitted with one of the most radical factory cam grinds of the day. It featured 299/290 degrees of duration and 0.441/0.439 inches of lift at 0.050 on the intake/exhaust, ground on a 109-degree center line. This grind helped air flow through restrictive head design and small 1.875/1.5 intake/exhaust valves, but left the stogdier Buick owners asking their dealers why their luxury liners ran so rough." Does anyone out there have a part number for this cam. Thanks and take care, Bill Bailey :jd:
Re: 59-61 401 CAM? Bill, I don't think it was 299 and 290 at .050. That would be one VERY radical cam. Jim Burek
o No: Jim, Thanks for the reply. I just re checked the above mentioned article and I quoated exactly as written in the 2001 Car Craft Magazine written by Tony Nausieda. That is why I wanted to post the info, to see if this was true and if so what part number would it be? The article continues as follows. "The LSA was toned down to 114 degrees for '62, but the" rump- rump"Buick idle (as quoated from Hot Rod's '65 GS road test) had already become famous-or,depending upon who you ask, infamous" I would go on farther, but this typing will take me all night. I would really love to know if this is straight scoop. What do you say Jim? Thanks again for all the help with my car and take care Jim. Bill Bailey
Bill, well, as I said, there is no way the cam has 299 degrees at .050. I'm sure it was supposed to be advertised duration. Buick seemed to be rather optimistic about their cams . A cam with 290 and 299 degrees of duration ay .050 would not idle at under say 1500 to 1800 rpm, period. Jim Burek
Jim, I would never doubt your opinions, I have great respect for your knowledge. Thanks again Jim. Bill Bailey
Buick used a lifter rise of 0.002" for their 'advertised' duration.....hence the big numbers! Most manufactures spec at 0.006" rise. The Buick cams were about 209 degrees at 0.050" lift. .....I know, old thread. Popped up in a Google search, couldn't resist!
Yeah that was a misprint on the article. From what I've researched, the '59 - '61 401 cams are the most aggressive. The '65 425 dual quad cam seems to be the same specs but 4 degrees retarded. Here's the kicker, I found a document from GM in '66 on how to factory mod the '66 GS for strip that stated to use the '59-'61 364 cam OR the '65 425 dual quad cam. I'm pretty sure the late 364 cam is the same as the "super Rivi" cam. I have one and will get around to degreeing it as soon as it cools off around here and I have some time.
The one thing that article does not show is the degree that valves opened and closed. Even though the duration, lift, and LSA are the same on some of those, it was the timing that was changed.
I know this is/was originally a very old thread that got some more recent input. But it helped point to something that I'm having difficulty with currently. I've been spending hours looking at threads that praise the old '091' cam so have been looking at many cam specs to find one close to it. How do I, as a novice, confidently compare todays offerings to those duration numbers? I think that for what I am building the '090' would be a better choice anyway. As a comparison, I see that Comp Cams now makes a few nail' specific cams, the mildest being their 'Thumpr' #91-600-5 with durations listed as 279* int. & 297* ex.,. What 'lifter rise' do we think they are using? Also, the lifts are stated as .478 int. and .465 exhaust - less ex. lift than intake(!). And 107 lobe spacing. The TA 112 lists durations of 260 int. & 262 ex. Steve
Okay, I think I get it now. Too much reading yesterday and read this thread at the end of the day, which was quite frustrating; most durations are listed at .06 lifter rise as opposed to Buicks .02 specs. I'm learning. Steve
Best to compare the 0.050" duration specs. I had profiled a stock '66 401 cam and got the following: Duration at 0.002" = 298* Intake, 309* Exhaust Duration at 0.006" = 266* Intake, 271.5* Exhaust Duration at 0.050" = 208* Intake, 209* Exhaust The Comp Thumper series cams are pretty big, the small one is 227/241 duration at 0.050". Andy here on the board is using one. Comp can put other grinds onto a Nailhead core. Take a look at the offerings for a more popular engine like a 400/455 Olds. It has 1.6 rocker ratio like our 401/425, so lift/duration specs will be close to a 401. Something like a 'High Energy' 260 is in the ballpark of a stock 401 '109' cam, with 212* duration, 0.447" lift with 110* lobe separation. The 'Extreme Energy' series offer faster opening valves and more exhaust duration. The XE256H, EX262, and XE268 look like decent street cams. Both GSGTX and Eric here on the board are using custom grind Comp cams. Carmen Faso offers a few custom grinds for Nailheads. Russ Martin also offers a cam he feels is close to the '109' cam.
if i was doing a near stock rebuilt with no head work, like Walt said comp will custom grind a cam. extreme energy 256 adv. with 212 @50 duration and 477 lift for the intake and 260 adv. with 212@50 duration with 474 lift for the exhaust. put it on 109 LSA like the 091 cam but with at least 10 extra horsepower then the 091 cam. off idle that will have a lot of torque blow the tires off ,LOL. then shift at 4800-5000 rpms and you will have a fun street car that will never blow up and last a long time. oh yea will need a stronger valve spring.
I used the 091 cam with my original skylark car.... along with a holley 950 cfm three barrel carb and loved it... still love it ,, wish I had a truckload of them... :Brow::laugh:
The "091" cam argument is probably the only thing I've never understood as it pertains to the Nailhead. I can see the benefits of the more aggressive lobe separation angle, but that is about it. It doesn't have enough duration and it doesn't have enough lift for a modern performance application. But maybe that's not your intent? I've played with many dyno simulation software's and modeled the Nailhead port profiles (focusing on the exhaust port) in ANSYS (FEA) during my ME undergrad. Bob - I still owe you your molds back, I apologize! The Nail tends to prefer a split profile grind with additional exhaust duration. As Walt noted, I am running the Thumpr from Comp. I was going to have them do a custom grind, but I found a Thumpr for dirt cheap and it was very close to my specs. If I had to do it over it would be 224*/236* @ .050" on a 108* with similar lift (due to valve to piston clearance issues). The Thumpr is 227*/241* @ .050" on 107*. More aggressive yes, but not excessive. The Thumpr still provides great torque and pulls to 5500rpm, although in my application it stops pulling ~5000rpms (with minimal head work).
