One huge gap in my engine knowledge is camshaft design. My 425 has a reground, therefore reduced base circle camshaft in it. Among other things, it necessitates longer then stock pushrods, which of course increase oscillating weight. I would post the cam specs here, but at the moment, I cannot locate my engine book. Ideally, I would like to replace my present cam with a new (not reground) cam, lifters, and stock length pushrods this winter. I know that there was a factory cam for the 401 back around 1959 or 60 that was pretty hot. I thought that I had heard it referred to as the Duntov cam. Does anyone know for sure what the specs were for that cam? Is it available? Can anyone make a suggestion based on personal experience as to what cam I should install in my .030 over 10:1 single 4 bbl. 425 for good all-around performance? I do not want solid lifters, I want a half-decent idle. I'm hoping that Tom Telesco will read this, but would be happy for any advice or suggestions. I will also need info. on sources for the parts. Thanks in advance.
John, that would be Doc's favorite cam - he refers to it as the Super Wildcat cam. I can't comment on this directly, as I'm unfortunately still running a stock cam, but I have played around quite extensively with multiple dyno programs, and have reviewed almost all of the builds that were dynoed here on V8. Here's what I will say. The Duntov Super Wildcat cam is still fairly mild. I've found that the 'Nail always prefers a split profile cam (as in more exhaust duration/lift than the intake). I think something like the TA-25 would be mild enough to do what your asking, and still provide a significant increase in horsepower without sacrificing any torque.
Here's a copy of the stock cam specs, from an old GSXtra article: Buick used a lifter rise figure around 0.002" to derive these duration specs. So their duration figures are only good for comparison between these stock cams! A stock '66 401 cam I measured has these specs: Intake: 0.448" lift / 209 degrees duration @ 0.050" Exhaust: 0.425" lift / 208 degrees duration @ 0.050"
Thanks Walt! That is really helpful. I appreciate your taking the time to find that list. I wish my printer would print the whole thing. It leaves off the two right columns - naturally the two I care most about. I will hand copy it.
hey john i just rebuilt my 425 went .030 on heads after market push rods org not avl. carmen in tonawanda ny has a lot of buick stuff my crankshaft had flat spots he had one in ex condition which we polish millied to specs and balanced with pushrods etc.we put in porformance cam went electronic ignigion and redid everything, on the dino at 4500 rpms 275 hp and 2700 rpms 427 tork food for thought went with 600 cfm holly seconddariy vac and found a 342 posi in texas awesome org has 308s one wheel grip,hope this helps also rockauto.com and opg.com. :beer
John,,,, yep, I do like the 091 cam,,,, it is a Duntov grind,,, it is the best all around cam for street/strip that I have seen,,,, it doesnt rattle your teeth out,:laugh: :laugh: at idle , idles at 850 rpm,,, works with power brakes, and will take big carbureation when you throw it to it.... throttle response is crisp and strong... wish I had a truck load of them.... On any given cam you can find some one who has a similar grind that they claim is better.... but the 091 is a torq cam that is designed for a torq engine and it works very well.... If I was in the market for a cam, I would , today, knowing what I know now, find some one who would take a blank and grind it to 091 specs....
If your cam journals are the same as a 401/425,,,,, I would say the same thing that I just said to John..... now be advised that I ran it with both a 2.93 gear and a 4.11 gear.... it ran strong with both.... With open exhausts it sounds good.....real good....
"wish I had a truck load of them..." Hi Doc, I'd settle for just one! I will be looking for one or something very close to it. Sounds like a winner. :grin:
I agree that. My engine pushed out few years ago in engine dyno 302hp with TA-25 cam,750 Edel and megaphone headers,nothin more.If i remember right,max torque was 440 ftlbs and i had generators and all other stuff installed.Idle was nice,about 800-850 rpm,like semi thrump sound.
cams have come a long way in the last few years.they make alot more power with a better idle.comp cams or a few others can custom grind one with a new core, your engine specs,gearing,how heavy your car is.
John, send me a PM with your phone number & a good time to call. It would take me days typing with one finger. Tom T.
Hmm...just gave me some food for thought; I'm now wondering what kind of a dog I bought with that engine kit for my 401; - it was a generic supposedly stock replacement cam; - now I'm beginning to wonder if it was a very generic "one application fits all" type of thing that in actuality doesn't do anything well. So how hard is it to get one of these '91 cams that Doc refers to? Can I get an old stock unit built up to those specs? Does anyone sell them new?
If you take the specs from the sheet and give them to a cam grinder, they should be able to grind one for you.... I am not saying that the 091 is the absolute best cam for a nailhead,,,, technology does progress... but it is the best that I have seen so far for all around street/strip and general driving... and we know that it will handle big carbureation....the mistake that i see a lot of guys make is putting on a set of super cat carbs without installing a hot cam....then they wonder why the car doesnt run like it should, or they go on in their ignorant bliss thinking that the car is really running strong...I once drove a 65 riv with such a set up on it and it was slower than the 64 that I have with just a holley 4 bbl... a cam has to be tempered after it is ground,,, this is important,,, in the old days they called it ''flame hardening''.... but there is a heating , cooling process that it has to go thru, that is why the cam is ash grey when it is new, and then gets a ''polish'' on it as it breaks in....be sure to include zddp when you put in the oil... and use moly GREASE when you install the cam and lifters into the engine,,, the grease will not drip off like the liquid stuff does....
I agree.....there are some better choices out there. The '091 Super Wildcat' cam is just a stock 425 cam.
Well walt, I very seldom disagree with you about anything...:laugh: but a 091 cam is not ''just a stock 425 cam''.... I have run the 091 and it definitly was hotter than just a bread and butter 425 cam... I have one of those in my 425 in my riv right now, and the 091 super cat cam was definitly hotter than that... the one that Iran sounded real good and lopey when the headers were open and pulled strong from 800 thru 6000.... not like the silky smooth idle of the cam in my riv now... and I agree with you that there have to have been advances since that cam was originally made up,,,, heck , back then a cam with a half inch lift was a big deal.... It was a ''stock'' cam in the sense that I bought it over the counter at my local Buick dealer....Or,,, am I mistaken about the cam part number.... maybe that it was not a 091 but some other number... superceded???? but never the less, a super cat cam.... and hotter than just a plain cam... by a bunch....
A stock '66 401 cam I measured has these specs: Intake: 0.448" lift / 209 degrees duration @ 0.050" Exhaust: 0.425" lift / 208 degrees duration @ 0.050" Walt this doesn't seem to make any sense. according to Denny's specs, a Nail should never have less exh lift OR duration than it has on the intake side. the exh lobe may match the intake profile but it's not supposed to be smaller. do we have any explanation for why you're showing more lift and duration on the intake side?
Doc, feel free to disagree with me anytime! I consider this a discussion, not an arguement!:grin: Here's what I got: The best source of stock cam specs I've found is the chart from Dennis Manner shown above....that shows the same cam for the 64-66 425 and the 2x4 models. Note that the 66 425 used the milder cam...due to complaints that customers' cars idled too rough! I checked my 66 parts book, and it shows 2 cams ....the '90' (400/401-425) and '91' (400 HD) shown above. There's no listing for a 2x4 since that option wasn't avail in early 66, at the time of the catalog printing. The 1972 parts book only shows the milder '90' cam....guess the '91' was discontinued. -2 magazine articles from the day say pretty much the same thing, but the Hot Rod article says the '91' cam has 0.461" lift, Buick says it's 0.439"-0.441". ...Either they listed the wrong spec, or the wrong cam #. -A letter from Buick to NASCAR drag division gives # 1362243 and 1362242 for 65 and 66 models, with the '42' being the hotter cam. Anyone have those numbers in a 1965 parts book? Maybe there were other cams avail, I just don't have the info. My best guess is you either purchased a cam not listed above, or you had a milder cam in your 64 than it should've....you say the '91' cam had a lumpier idle than the original....that could be the difference between the 109 and 114 degree lobe centers. I hope there WAS a hotter cam avail from Buick, I just don't have the data yet....that's all I got. Bob, that's what I measured (carefully) on a used original cam. Lobe lift was 0.261 on the exhaust and 0.267 on the intake. Measured lift at valve was 0.425/0.448. Computing the rocker arm ratio yields a 1.628 for the exhaust, and a higher 1.678 ratio for the intake....so apparently the production geometry wasn't perfect, at least after 65,000 miles. Using a straight 1.6 rocker ratio on my lobe lifts would yield 0.418 ex, and 0.427 on the intake....both under the 0.431" 'spec' by 3% and 0.9% respectively. At this time, I can't say whether that's due to wear or production tolerances.....probably a little of both o No: Now if all the Nailheaders out there would measure their cams, maybe we could get enough data to make some real progress!:grin:
After reading this thread, I thought Zora Arkus Duntov worked for Chevrolet engineering, and Denny Manner was the Engineering Director behind the Super Wildcat program. My question is: for historical purposes, at what level was Mr. Duntov involved in designing Buick nailhead cams? I never heard of this. Thanks, Ken
