318 cam

-
6

65Dart270Sedan

Member
Joined
Jun 18, 2023
Messages
13
Reaction score
0
Location
Tennessee
What is the biggest cam you can put in a LA 318? I saw something about you can’t put high lift cams in them without grinding down the valve stem guides. Also, what mods other than springs will need to be done?
 
Last edited:
With NO modifications (assuming a 318 2bbl.)- not upgrading the springs, not eliminating the valve rotators (if present), or anything else, then just slap a stock 360 2bbl. cam in there: 278/278 .410/.410. It's not much, but the rest of the valvetrain isn't going to handle much more than the stock 318's 240/248 .373/.400 cam.
 
Lift limit is .450 at best but the springs are old and may not handle it.

Getting springs, retainers and locks should be part of the whole deal and not “JUST” a cam change. It’ll be worth saving the money and waiting on the time to do it right & at once for a noticeable difference.
 
rumblefish360 said:
Lift limit is .450 at best but the springs are old and may not handle it.

Getting springs, retainers and locks should be part of the whole deal and not “JUST” a cam change. It’ll be worth saving the money and waiting on the time to do it right & at once for a noticeable difference.
Click to expand...
I think with the valve rotators, even .450 might be pushing it.
 
I've never had a 318 with valve rotators.

I currently have four from 1968 to 1987.

What did they come on?
 
I have personally installed the MP .474/280 cam in an otherwise complete stock 318 and I had no issues. I later upgraded my valve springs to match the cam. No, this is not a recommendation, it is an answer to the question by the OP's 1st post.
 
318willrun said:
I have personally installed the MP .474/280 cam in an otherwise complete stock 318 and I had no issues. I later upgraded my valve springs to match the cam. No, this is not a recommendation, it is an answer to the question by the OP's 1st post.
Click to expand...
I assume you had some non stock converter.
In my stock 1972 340 Challenger with Stock J Heads it needed a small one. Used a, Street Fairbanks one. What they markered as a modified Hemi. Was a,step above the neutral balanced 340/440 one's every one looks for as,Dayco rebuilt 340 converter.
The 274 MP cam needed a little more than my stock 340 one to run well. With 323 gears
 
I’ve yet to see a 318 that didn’t come without rotators… but, many were Jasper or other suppliers rebuild engines or later truck engines.
 
340six said:
I assume you had some non stock converter.
In my stock 1972 340 Challenger with Stock J Heads it needed a small one. Used a, Street Fairbanks one. What they markered as a modified Hemi. Was a,step above the neutral balanced 340/440 one's every one looks for as,Dayco rebuilt 340 converter.
The 274 MP cam needed a little more than my stock 340 one to run well. With 323 gears
Click to expand...
i had stock converter, 2.76 gears and stock exhaust manifolds. Again, not what I recommend but it's what I did.
 
If it was one of the 106 or 108 LSA cams installed four to eight degrees advanced, it probably ran better than expected…
 
318willrun said:
this is the cam i installed bought through Western Auto parts store (remember them?)

Mopar Performance P4452992AE Mopar Performance Purple Camshaft Kits | Summit Racing
Click to expand...
My good friend i grew up.with Chuck worked there and became manager and was untill closed up. He bought plenty stuff for me with his discount.
Sorry to run off tract.
I think we have always run stuff since that's what we had unless you were the rich kid.
I blew a 340 up got a short block at junk could not afford the used long block or assy to have spares.
Used 72-73 low compression 340 short block. Used J Heads, a tuned Holley 3310, MP 508 solid And swapped to 276 sure grip i found under a C Body. I ran the interstate from LA. To South Mississppi real well. To my place in Mississippi on weekends
 
318willrun said:
I have personally installed the MP .474/280 cam in an otherwise complete stock 318 and I had no issues. I later upgraded my valve springs to match the cam. No, this is not a recommendation, it is an answer to the question by the OP's 1st post.
Click to expand...
Old springs are good for cam break in , then upgrade them later
 
The biggest aftermarket cam I’d feel okay “recommending“ for a totally stock 318 is an Isky 256 Supercam.

And even that might be more than the stock springs are capable of dealing with at higher rpm.

The 2bbl 360 cam is fine, since they use the same springs as a 318.
 
Garrett Ellison said:
If it was one of the 106 or 108 LSA cams installed four to eight degrees advanced, it probably ran better than expected…
Click to expand...
The cam should have 4*’s ground into it as delivered. Advancing the cam without trying it as is installed as it should be first would be a waste of time as there is no footing to compare it to.
 
I’ve seen some rotators on single groove valves before, but most of the aftermarket rebuilder engines (and a lot of stock 360!) have two groove exhaust valves. If it’s got the rotator setup with two groove exhaust valves, you’re better off just having another set of heads to put on. You won’t actually know which one is under the rotators until you take one of them off, so it can be a crap shoot.
 
For performance applications, I replace the two groove valve/rotator combo with a 4 groove valve and std retainer.

I’ve only seen rotators on truck/industrial engines.
 
You must log in or register to reply here.
-

Back
Top