Lets spec out a roller cam for my LA 318

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bschubarg

bschubarg

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I have an '87 Chrysler 5th Ave. Yes, I realize this isn't an A-Body, but when it comes to spec'ing out a camshaft for the 318 small block, the rules apply to any Mopar body.

About the car:
Current Curb Weight - 3450 lbs
I removed a lot of
unnecessary weight and weighed it myself

Rear Axle Gear: 3.55
8.25 Sure Grip

Tires: 17x8.5 275 40 17

Transmission: 904 Auto

Engine:
LA Roller 318
Compression 9.0 Static
Heads 302 1.88 Intake, 1.60 Exhaust Comp 901 Springs
Intake Weiand Stealth 8002
Carb Holley Street Avenger 670 CFM Vac Sec
Headers 1 5/8 Long Tubes 3" collectors

Purpose:
The car will be a daily driver with the occasional trip to the 1/8 mile track near by.
Gas mileage is not a concern but reliability and road manners are of concern(over heating, very rough idle, excessive wear etc....).

The engine only has 70K and after removing the heads, the bore measured with less than .005 wear. Compression test showed an average of 155 psi. There fore I will run with what I have. Standard bore and stroke.

The heads are #302 and have been ported and gasket matched. Port involve bowl enlargement to handle the oversize valves and a lot of attention to un-shrouding the valves in the combustion chamber. Stock flow for 302 is around 175 cfm. Although I have not flowed these ported heads, I will feel confident that they flow 200+ cfm.

This 318 came from the factory with a roller cam along with all the supporting hardware.

So... given the above information I would like to regrind the original roller cam to what ever the consensus is from this post. Whoever regrinds the cam will also be what the consensus.

Why not just buy a new roller or call one of the many cam designers...? Well I guess I could...like everyone else...but this approach will help me what look for in camshafts and this ought to be yet another learning experience.

What makes this post different than the hundreds of posts here on FABO with respect to camshaft advice...? Because every one who contributes advice will see the result as I promise to have the cam reground by the consensus with the specifications by the consensus and will install the cam myself.

Time Frame:
Installed and running 1st week of Feb 2018; Regrounding company permitting.
 
I would look through the catologs of major cam companys and focus on cams with power ranges of 1,000/1500 to 4800/5400 roughly. Then call your cam grinder and get thier opinion as well as what they can do with your stock core. With only 318 cubes and stock compression personally i would shoot for more lift with a moderate increase in duration to keep that 2,000 rpm efficiency for best mileage.
 
Hughes Engines has a bunch of hydraulic roller grinds and so does Comp Cams. I got the hydraulic roller Comp from Summit Racing.


gregsdart said:
I would look through the catologs of major cam companys and focus on cams with power ranges of 1,000/1500 to 4800/5400 roughly. Then call your cam grinder and get thier opinion as well as what they can do with your stock core. With only 318 cubes and stock compression personally i would shoot for more lift with a moderate increase in duration to keep that 2,000 rpm efficiency for best mileage.
Click to expand...
 
I can't help on an answer but this exact build has been on my list for years with the only exception being an A-500 transmission.
This is gonna be sweet
 
I too have a roller 318 block and 302 heads waiting for a build. With the right cam and the op's parts selection so far, I don't see why he wouldn't see 350-375 horse if he wants to go that far. A performance converter would be a plus with much of a cam.
 
got the same motor and heads but im going different direction. just a toy with some 1/8 mile 7.49 braket rounds so manners and streetability or mpg not needed! came cross a deal on a brand new roller cam, 235 249 @.50 .522 .509 107° but gotta lotta head work to do!
 
215/220 @ 0.050" and what ever lift they cut from the stock cam .475 to .500 would be good.
 
I'm close to the same boat with a back burner project.

I have an 86 318 roller and some 2000 Mag heads.

I recently bought this-

Voodoo Hydraulic Roller Cam - Chrysler 273-360 (W/ Long Snout) 258/264 - Lunati Power

from a member on FxBO.

Lift ends up a .517 with 1.6 Magnum rockers, which is just under the normally accepted .520 max before machine work is required.

That line has the long snout for the mechanical fuel pump.


How did you verify the 9.0:1? Are they the stock pistons?

Those motors are advertised as 9.2:1, but a lot of folks don't realize it.
 
YY1 said:
I'm close to the same boat with a back burner project.

I have an 86 318 roller and some 2000 Mag heads.

I recently bought this-

Voodoo Hydraulic Roller Cam - Chrysler 273-360 (W/ Long Snout) 258/264 - Lunati Power

from a member on FxBO.

Lift ends up a .517 with 1.6 Magnum rockers, which is just under the normally accepted .520 max before machine work is required.

That line has the long snout for the mechanical fuel pump.


How did you verify the 9.0:1? Are they the stock pistons?

Those motors are advertised as 9.2:1, but a lot of folks don't realize it.
Click to expand...
It should work well
 
adjustable valve gear could be needed if cam is
reground a lot? I have 2 of these 318 roller motors
currently running. 1 of them I sent the factory cam to Delta Cams specs: 205/208 .450/.470 110 cl installed 4 deg advanced (automatic car) has loads of torque, idles 18in revs very good to over 5K.
The other has a Hughes 208/214 .480/.490 114 cl installed straight up (4 spd)seems
a little softer on low end but comes on stronger above 3k, idles about 17in this was a reground from Hughes seemed to have lifter pump up issues when cold, I installed 273 adjustables seems to have eliminated cold noise for the most part. Thinking about Rhodes roller lifters
to improve low end. Would recommend either in
your case, I would either degee cam CL or advance cam. You can also look at Magnum cams and get a snout extender from Hughes (using on Hughes OK) Before choosing do a compression test to get an idea of what size cam to use (thin head gaskets) if low. I run
87 octane fine.
 
Still curious about the 9:1 measurement.
 
bschubarg said:
I have an '87 Chrysler 5th Ave. Yes, I realize this isn't an A-Body, but when it comes to spec'ing out a camshaft for the 318 small block, the rules apply to any Mopar body.

About the car:
Current Curb Weight - 3450 lbs
I removed a lot of
unnecessary weight and weighed it myself

Rear Axle Gear: 3.55
8.25 Sure Grip

Tires: 17x8.5 275 40 17

Transmission: 904 Auto

Engine:
LA Roller 318
Compression 9.0 Static
Heads 302 1.88 Intake, 1.60 Exhaust Comp 901 Springs
Intake Weiand Stealth 8002
Carb Holley Street Avenger 670 CFM Vac Sec
Headers 1 5/8 Long Tubes 3" collectors

Purpose:
The car will be a daily driver with the occasional trip to the 1/8 mile track near by.
Gas mileage is not a concern but reliability and road manners are of concern(over heating, very rough idle, excessive wear etc....).

The engine only has 70K and after removing the heads, the bore measured with less than .005 wear. Compression test showed an average of 155 psi. There fore I will run with what I have. Standard bore and stroke.

The heads are #302 and have been ported and gasket matched. Port involve bowl enlargement to handle the oversize valves and a lot of attention to un-shrouding the valves in the combustion chamber. Stock flow for 302 is around 175 cfm. Although I have not flowed these ported heads, I will feel confident that they flow 200+ cfm.

This 318 came from the factory with a roller cam along with all the supporting hardware.

So... given the above information I would like to regrind the original roller cam to what ever the consensus is from this post. Whoever regrinds the cam will also be what the consensus.

Why not just buy a new roller or call one of the many cam designers...? Well I guess I could...like everyone else...but this approach will help me what look for in camshafts and this ought to be yet another learning experience.

What makes this post different than the hundreds of posts here on FABO with respect to camshaft advice...? Because every one who contributes advice will see the result as I promise to have the cam reground by the consensus with the specifications by the consensus and will install the cam myself.

Time Frame:
Installed and running 1st week of Feb 2018; Regrounding company permitting.
Click to expand...
Takes mucho porting to make the 1.88 work like it should. So if you only opened the bowl and chamber un shrouding, its not flowing 200 + cfm. I haven't seen them, so I can't say that's the final word on them but I do know that runner , short turn and all above it needs much material removal.
 
The 9.0 is the limiting factor. Any cam you put into it, bigger than the current one, will drop cylinder pressure.
155 ain't bad, and presupposes an ICA of around 52*. The next bigger cam may drop the pressure to 150, and the next to 145, and so on.By 145 it's gonna be kindof a dog, off the line, and you'll be needing a much bigger TC.
Each 5 psi pressure loss, is easy to feel from idle to perhaps 3000rpm;so,at typical speeds your 5th is gonna see.
Your auto should actually be an A998/A999, if so it will have ratios of 2.74-1.54-1.00. But if indeed an A904, then your tires and 3.55s suggest gearing of 8.6 mph per 1000 rpm in first gear. That calculates out to 43MPH at 5000 rpm. When it shifts the Rs will drop from that 5000 to 2950, so there better be some torque down there, if you want to continue. The 2.74 low gear will make this even worse. If you put too much cam into it, she'll have a tuff time climbing up outta this hole.
Of course the solution is only a convertor away.
So, it looks like with a 9/1 engine, you'll be limited to exactly one cam size bigger than you currently have.
Remind me again what cam is in it now?

IMHO , I suggest you keep the current cam,(or a similarly sized cam with more lift to go with your new headflow),get a bigger TC, and up the rear gears. This will get you waay more performance. It will be like a supercharger.
The next bigger cam might make a few hp more at say 4800rpm,which you can't get to until close to 40 mph,with a probable loss of torque at the factory stall, and continuing a declining loss until maybe 3000(guessing).
But a bigger TC will get you an instant punch off the line from mild to wild, depending on what you choose. Bigger gears will let the engine run thru each ratio quicker, and put down more average hp during the course of the run, and get your zero-to-whatever time, down.
Jus saying
 
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