I’m hoping some of you cam experts can help me select a good cam for my 440 build. The motor is a low performance, low mileage 440 from a mid 70s motor home. It is currently in my 1969 Dodge Coronet RT (3800 lb car) with 3.23 gears and an automatic. Four barrel and headers. It runs nice and has decent power but I’m pulling it to fix oil leaks. While it’s out, this is a good chance to do a cam swap while I’m cleaning it up and resealing it. I’ve measured how far the piston sits in the hole and cc’d the heads. As it is now, the compression ratio is a disappointing 8.15 to 1. I have a better set of iron heads with smaller chambers. That and thin gaskets can get me to 8.95 to 1. I’m not looking to race and I don’t need 400 plus horsepower. I just want a modest bump if the sub 9 to 1 compression ratio will allow it. In fact, I do not want it to rump and shake at idle and I want 15” plus of vacuum at idle. I plan to reuse the stock, stamped rocker arms and pushrods so lift can’t be drastically different from what’s in it now. I believe the current smog cam has the following stats: Intake duration 260 Exhaust duration 268 I’m told they didn’t measure duration @ .050” lift back then so this is all I can find. Valve overlap 38 Intake lift .434” Exhaust lift .430” Intake opens 18 BTDC Intake closes 62 ABDC Exhaust opens 68 BBDC Exhaust closes 20 ATDC Could not find information on factory lobe separation angles but I’m guessing it will be around 115-117 I’ve read tons of articles on cam science and it’s helped me understand but I don’t want to over ****yze this when I have work to do and there are folks who understand it far better. Appreciate the input but please refrain from recommending I just leave it alone or I should rebuild the motor with taller pistons, I should do other engine improvements, etc. Only looking for advice on finding a nice cam one step up from the stock one in it now. One of the cams I was considering is the Lunati Voodoo (smallest version) Advertised duration 253/258 @ .050” 208/213 Lift .454” LSA 112 Intake centerline 108 Is this profile a bit too much for an engine with a CR under 9 to 1? What stats should I be examining to ensure it works well with a lower compression motor? I’ve been rejecting anything with LSA tighter than 112 for fear of it falling flat or for producing too little vacuum at idle.
Big thing...keep the lobe seperation no more than 112°, 110° might be better. I've got a slightly warm, (factory heads) 440 that I just bought into. It's got a 108° L.C. flat tappet cam. It runs better than the lift and duration spec.s, give it a right to ! Only supercharged (belt driven) or very high rpm, largs inch, engines like large lobe center angles. Mike
Call a good cam manufacturer, they do this stuff daily. Regardless, I can tell you from experience with a very similar combo, you are not going to see any big improvement. I had a '64 Dodge 330 with a mid '70's 440. Low compression and basically stock heads. I went through the same thing. It seemed a little snappier after I moved up in cam, but not enough to justify the effort. In hind sight, I should have put a stroker crank in it....
I’ve been trying but no one answers phones these days. And it’s really no effort at all. The motor has to come out anyway for cleaning and resealing. Someday, it will get a proper rebuild and maybe a stroker kit then. For now, all I lose is cost of cam and lifters. I think if I were reusing the original 92cc heads with 8.1 compression, I’d feel very little improvement but with the smaller heads along with a bump up on the cam, I should notice some improvement. if not, its no big deal.
I’m not going to recommend any certain range of numbers to look for, but will recommend this—- retrofit it to roller lifters. It won’t be cheap, but with the current garbage being sold on the market now, it should be cheaper than having to go back into it again and having to replace stuff wiped out by ****py cams and lifters.
I'm sure you meant that while you have the engine out, you are prepping it for installation in a pre 1966 on topic car!
If you have power brakes, I would not go tighter than a 112 LSA. Break-in of flat-tappet cams is a concern. A billet retro-roller would be better, if your budget will allow it. Finding quality hydraulic lifters, whether or not rollers, can be a problem. With a static compression ratio of less than 9:1, you need to be conservative with duration. UEM Pistons has a good online calculator for both static and dynamic CR. I would shoot for a DCR of just under 8:1. You didn't say how far down the hole the pistons are. You need to take that into consideration, as well as head gasket compressed thickness, and shoot for a quench as close to .040 as you can get to avoid detonation. I cannot comment on the Lunati cam without knowing the stock cam specs at .050. Advertised duration/duration @ .006 isn't helpful. Rather than investing in a stroker kit, I would spend the money on better heads.
I'm getting the wish for an RV cam. That is what it was intended for. Seat of the pants off rhe line is most satisfying. No need to wind it up to have it pull hard. Been there done that, most pleasant when dicing in traffic
I was thinking the same thing as I read the responses. When I built the 454 for the ‘58 I used an Edelbrock Performer+ RV cam, it has similar lift and slightly more duration than the specs in the OP. It’s well mannered, has plenty of vacuum for power brakes and makes gobs of torque where you need it, from off idle to around 4500 rpm, and works with a stock converter. Drivability is excellent…
My experience says to focus on compression. Good c/r with a mild cam is better than weak c/r with too much cam. These heads can be a detonation problem if quench is not right so that has to be sorted out. How many miles on the engine? Have you been able to check the bores for wear? (ridge, round, taper) The 9th edition of MaMopar's engine book says the best cam for a low rpm grunter is the, now old, P4286673 with 248°- 0.410" lift and only 20° overlap. The low overlap traps more cylinder pressure and makes the cam feel bigger. You could probably add a little to the lift/dur but keep the overlap down.
That’s what I was thinking on the wider LSA. I have power brakes and I’ve picked tighter lsa cams on cars only to have low vacuum at idle. I can’t justify any big expenses on this motor right away. In a few years when other projects are finished, sure. Pistons are down .100” in the hole because it’s a mid 70s low compression smog motor. I won’t have quench no matter what I do and pinging/valve clearance issues won’t be my problem. I’ve already measured everything and used an online calculator to determine I will end up with 8.6-8.95 CR depending on the gasket I choose. Basically, I’m searching for an RV cam that will work with lower CR.
yeah, I should have said RV cam since that’s basically what I’m looking for. Something stouter than the original smog cam (if possible) but not so much that it won’t work with a lower CR
I agree. The low CR is definitely on my mind. I’ve picked lots of big cams in my youth that all had zero power because they were too big. The motor definitely has wear and tear but I don’t care to rebuild it at this time. It runs nice, makes no noises, has lots of power and doesn’t smoke. Even if it only had 10,000 miles left in it, that’s many years of use at the rate I drive it. I’ll see if I can find something with less overlap but if it’s simply a duplicate of the original smog cam that’s in it now, I might as well stick with what I have.
I had a 440 6 pack short block in the crewcab that I used to pull the race car with. It would be similar to your setup. Low comp. is the real down side. I was a believer in the purple shaft series but with your comp. ratio, better sound might be all you get.
Actually, they had a dozen different cams for just about any build project. I can post the list if anyone wants/needs the info. As to being an OT subject, there are plenty of projects that can use some of this info. The engine series came to life in 1958 so not exactly new.
The Jalopy Journal
