solid cam??

[arizona satellite]

I am putting together a 440 and was thinking of using the mopar performance 312/ 590 solid cam. Actually the engine is done but has not been installed or even started and the idea of changing the cam to a solid type came to mind. Let me give you the specs on the engine as it stands now. std bore RV block, KB 236 pistons with the quench dome milled off, H beam rods with ARP 2000 cap bolts, a .010-.010 steel crank, the current cam is a comp 305H with .525" lift. the heads are 440 source stealth units with the locks upgraded and the springs checked the engine is topped off by a Edelbrock torker II single plane manifold. I am currently using the stock valvetrain but have both procomp 1.6 stainless roller rockers and 440 source roller rockers also in 1.6 ratio. I plan on using a 850 HP holley carb with a 4 corner idle circuit. from what I have laid out what is your opinion on the solid lift cam? this will be an automatic with a 4,000 stall and 4.56 gears in a 67 satellite. thanks.

 

[kidmopar]

i got one in my 66 satellite and i really like it, it has a 5000 stall and 456 gears also.. be sure you have piston to valve clearance and install the correct valvesprings my timing is on 34 degrees and i degreed the cam in also. i run two 500 cfm edelbrocks on a weiand single plane low rise intake

 

[IQ52]

Well, I suppose it depends upon what you expect from the change. The stock Stealth head flows 255 cfm @ .500" and 267 cfm @ .600". Changing from the 305H to the 312/590 with 1.6 rockers, will gain approximately 9.5 HP on the top end. Considering the extra overlap that the 312 has, you will lose some on the bottom. So I figure you'll about break even, average power wise, but gain a little rpm even though both cams should be rated 3500-6500 rpm.

If it was me, I'd put the 1.6 roller rockers on the 305H with the 867-16 hydraulic lifters, set the preload at .000-.004" and figure I had the same performance, for less cost.

Because, .525" lift on a hydraulic cam w/1.6 rocker = .560" lift. .590" lift with 1.6 rocker = .629" lift - .030 lash = .599" lift or maybe 9.5 HP gain with Stealth heads and the 312/.590 cam. If you have a Stealth head that is cleaned up like the RPM head you might gain 13.7 HP

But that is just me. If YOU want to put the solid cam in there, do it. I like solid cams.

 

[arizona satellite]

thanks for the input. I too like the sound of a solid cam and the extra rpm does not hurt either. I have been hording parts for another 440 build and think I may put the 305H into that stockpile.the power gain is not that great unless I have the heads worked on, I do know a BUNCH of stock eliminator guys with all kinds of tricks up their sleeves"). I may just drop the heads off at their shop and see what they can do.

 

[IQ52]

The Stealth heads can be pretty amazing. We've had them go 308 cfm @ .500", 337 cfm @ .600" and 346 cfm @ .700".

 

[lewtot184]

from the information i've read i think i'd want a little more compression with the 312 cam. i like soilds and they make a lot more sense than big hydraulics.

 

[IQ52]

We tend to get hung up on compression ratio for no other reason than we've read that you gotta have it to run good. Not true.

Mostly we need to concentrate on airflow.

A wise old man (my dad) once told me, "Jimmy, there are three secrets to making horsepower. The first two are cylinderheads. Third, and most important, is cylinderheads!"

Add 10% airflow and you get 10% more horsepower. Add 10% more compression (approximately one point of compression) and you get 2.4-4.8% more horsepower.

Right now the OP is probably running 9.4-9.7:1 compression.

We built our first 451 with 9.5:1 compression. Using 452 heads that flowed around 285 cfm @ .600", we made 621 HP and 588 lb-ft.......500+ lb-ft from 3500-6300 rpm and 501.8 hp @ 4500 rpm to 593.4 hp @ 6800 where we shut it off. That cam was 254/260 @ .050".

 

[arizona satellite]

the comp that I get from the KB site puts the comp at 10.6 to 1. granted this is a generic comp calculator but it does take all given specs into consideration. I really appreciate all the input IQ52. I have found your insight beyond helpful in previous posts, you most certainly are an asset to this forum. Thank You

 

[Meep-Meep]

I'm no pro engine builder, but I have participated in the effects of big cams and low compression and frankly it's pathetic. Perhaps I did something wrong? Idle vacuum is low and carbs don't seem to function correctly. I have always focused on very drivable street engines that you can pretty much just do basic maintenance to for thousands of miles, and the mods are very conservative and low cost and have a pretty good performance per dollar ratio. Huge cams are great for making max power but at what cost for a street engine? High valve spring pressures to wear the cam out faster? Valve to piston clearance adjustments? Extra emphasis on the valve train components to deal with the high spring pressures and lifts? Frequent valve adjustments because parts are wearing out? Solid cams are great but most grinds still require a considerable amount of valve spring pressure because after all they are meant for high RPM power. And some are not considered smooth profiles, thus requiring more spring, but they do make power (as your 451 data shows). You always give up something when dealing with engines and you just have to choose what you want to give up. I'm pretty sure the average driver / occasional racer wants to spend more time in the car than under it and not keep sinking more money in it than is necessary. But telling people that I'm running a .693" lift cam with 1.6 ratios rockers and triple springs does sound impressive at the parking lot show.

I'll be building a mild roller cam motor soon but it will be more for race duty than commuting. It will however see street duty on occasion and I'll be thankful for the MSD to keep the plugs clean for the time I spend under 3000 RPM. The cam is a roller version of the old Isky 1012B. .540" lift / 320 duration on a 108 LC. So are you saying I can run this cam with 8.0:1 compression and expect good results?

 

[IQ52]

I'm no pro engine builder, but I have participated in the effects of big cams and low compression and frankly it's pathetic. Perhaps I did something wrong? Idle vacuum is low and carbs don't seem to function correctly. I have always focused on very drivable street engines that you can pretty much just do basic maintenance to for thousands of miles, and the mods are very conservative and low cost and have a pretty good performance per dollar ratio. Huge cams are great for making max power but at what cost for a street engine? High valve spring pressures to wear the cam out faster? Valve to piston clearance adjustments? Extra emphasis on the valve train components to deal with the high spring pressures and lifts? Frequent valve adjustments because parts are wearing out? Solid cams are great but most grinds still require a considerable amount of valve spring pressure because after all they are meant for high RPM power. And some are not considered smooth profiles, thus requiring more spring, but they do make power (as your 451 data shows). You always give up something when dealing with engines and you just have to choose what you want to give up. I'm pretty sure the average driver / occasional racer wants to spend more time in the car than under it and not keep sinking more money in it than is necessary. But telling people that I'm running a .693" lift cam with 1.6 ratios rockers and triple springs does sound impressive at the parking lot show.

I'll be building a mild roller cam motor soon but it will be more for race duty than commuting. It will however see street duty on occasion and I'll be thankful for the MSD to keep the plugs clean for the time I spend under 3000 RPM. The cam is a roller version of the old Isky 1012B. .540" lift / 320 duration on a 108 LC. So are you saying I can run this cam with 8.0:1 compression and expect good results?

Do you think I'm saying run a cam like that at 8.0:1? Can you point to a post where I advocated that?

What I'm guessing the recommended compression would be, is around 12:1 with race fuel. Now, not knowing how a roller version of the old Isky 1012B is ground for lift at .050, the desired fuel type, combustion chamber shape and the rest of the build, I would say the preferable, usable options, lay somewhere from 10.5:1 to 13.0:1.

 

[Meep-Meep]

Do you think I'm saying run a cam like that at 8.0:1? Can you point to a post where I advocated that?

What I'm guessing the recommended compression would be, is around 12:1 with race fuel. Now, not knowing how a roller version of the old Isky 1012B is ground for lift at .050, the desired fuel type, combustion chamber shape and the rest of the build, I would say the preferable, usable options, lay somewhere from 10.5:1 to 13.0:1.

Never seen it and I never expected you or anyone else in their right mind to make such a claim. I just wanted to point out that compression must be considered when choosing a cam. Your opening line that says (paraphrasing a bit) "you don't need it to run good" may be taken the wrong way.

I don't have the lift @ .050" of my RR1012B but I can find out easy enough. I do know it's a symmetrical grind with 270 deg duration @ .050". It's also nice to see your gut feeling about the target compression range as I planned to run 11:1 with a small dome piston or possibly a flat top if I can make the numbers work.

 

[IQ52]

I should have said intake closing @ .050". The lift @ .050" will probably be real close to, well, .045-.080", depending on the rocker ratio, lifter type and valve lash. You're real close to what I consider pump gas range.

 

[Meep-Meep]

Intake closing is a big deal and I would think it should be checked at less then .050". One thought is when the valve is off it's seat you are loosing cylinder pressure, but the amount of time the piston moves from 0.0" to .050" isn't very much so perhaps it's more relevant to just check at .050".

I am not expecting this to run on straight pump gas! Maybe a splash of 110 or just run the VP 100. I can get that at the pump near my work.

I have the Isky lifters with it and rev kit and will run 1.5 rockers. Lash is probably .028" - .032".

I didn't mean to hijack the OP's thread but I suppose it's all relevant information.

 

[IQ52]

I use less than .050" lift, but I reference everything from .050". You have to start from someplace each time and I have chosen .050" because the cam manufactures have that information readily available.