I am trying to decide on which cam to pick for my 1968 318 with NP435 4 speed (D100 TRUCK) 3:23 GEARS - mostly around town driving with some highway time a few times per year. Occasional hauling loads.

I am going 30 over and keeping the stock crank. I am looking for fuel economy and low end while staying with smooth Idle.

I've seen the Comp 252 recommended but the shop recommended the Lunati 10200700 or the Erson E420101....

BRAND COMP Cams
Manufacturer's Part Number CL20-208-2
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 800-4,800
Intake Duration at 050 inch Lift 206
Exhaust Duration at 050 inch Lift 206
Duration at 050 inch Lift 206 int./206 exh.
Advertised Intake Duration 252
Advertised Exhaust Duration 252
Advertised Duration 252 int./252 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.425 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.425 in.
Valve Lift with Factory Rocker Arm Ratio 0.425 int./0.425 exh.
Lobe Separation (degrees) 110
Grind Number 252H

BRAND Lunati
Manufacturer's Part Number 10200700
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 1,000-5,000
Intake Duration at 050 inch Lift 208
Exhaust Duration at 050 inch Lift 213
Duration at 050 inch Lift 208 int./213 exh.
Advertised Intake Duration 250
Advertised Exhaust Duration 256
Advertised Duration 250 int./256 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.454 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.454 in.
Valve Lift with Factory Rocker Arm Ratio 0.454 int./0.454 exh.
Lobe Separation (degrees) 112
Grind Number


BRAND Erson Cams
Manufacturer's Part Number E420101
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 1,000-4,000
Intake Duration at 050 inch Lift 208
Exhaust Duration at 050 inch Lift 208
Duration at 050 inch Lift 208 int./208 exh.
Advertised Intake Duration 280
Advertised Exhaust Duration 280
Advertised Duration 280 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.420 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.420 in.
Valve Lift with Factory Rocker Arm Ratio 0.420 int./0.420 exh.
Lobe Separation (degrees) 111
Grind Number RV10H

hi wally , with 3.23 's and it being a truck what size tires and rims on this rig ? . Ronnie

Hey Ronnie, 235 75R15 my friend!

You are going to need all the torque you can get from idle to about 4000 rpm. The Comp cam you have listed doesn't sound like a bad choice. What compression ratio are you going to end up with? Have you called Comp and asked their recommendation for your application? If you call them with the specs on your engine, trans, gears, tire size, vehicle weight and intended use, they can recommend which cam will work best for you.

Thanks, I'll do that tomorrow. That is what popped up in a few previous threads. I appreciate it.

The Comp and Erson cams really aren't much bigger than a stock 360 cam.

My favorite cam for a 318 is the stock 340 cam.

Both the 340 and 360 stock replacement cams are way cheaper than an aftermarket cam last time I checked.

Comp $225 - summit
Lunati $150 - summit
Erson out of stock everywhere I could find a listing

340 cam $90 - Rockauto
360 cam $78 - Rockauto

None with lifters as that ought to be a wash as far as cost.

340 cam might be a bit too much for your truck, the 360 cam ought to be ok.

CR will also be a factor, but I like the Lunati #s, with the additional lift and wider LC.
I wouldn't run more than 9.5:1 with iron heads, though, with any of those 3.
There are 2 340 cams, the 4-speed cam in '68 was a bit stronger.
Either 340 or 360 would work.

I haven't had any luck finding a new 68 340 4 speed cam for a long time.

Yep.

But I have a Delta regrind 68 4 speed cam in my 360 and its have been good. They reground my 360 OEM cam core.

hi
68 318 will have good compresion if the replacment pistos are not lower than stock .

tell th shop to check the c.h. !

if you keep stock compression when finished get crane 6993902 power max cam & lifter kit summit / jeggs call and give them the part no.

Thanks all, keep it coming. I'll find out what actual compression will be.

Remember that I am not looking for a lumpy cam.....

The addition of a 4bbl will be a better upgrade than a cam swap.

I like the 360-2bbl cam in a combo like that(works with stock everything).

This is a new rebuild in the stock 318 from the truck


Ok, Comp got back to me. This grind looks very similar to the Lunati that the shop recommended (if so, the question is which between the 2 now):

COMP recommendation

BRAND COMP
Manufacturer's Part Number XE250H
Summit Racing Part Number
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 800-4,800
Intake Duration at 050 inch Lift 206
Exhaust Duration at 050 inch Lift 212
Advertised Intake Duration 250
Advertised Exhaust Duration 260
Intake Valve Lift with Factory Rocker Arm Ratio 0.432
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.444
Valve Lift with Factory Rocker Arm Ratio
Lobe Separation (degrees) 110
Grind Number

Venezuela and Mexico Chrysler sectionals offered a 318 4 bbls engine with the 340 cam and 10:1 pistons ( advertised )
México on their 68-70 GTS versions ( can't recall if laters too )
Venezuela on 70 Coronets and 71/72 Chargers. Venezuelan cars got in fact the engines made in Mexico. 727, 3:23 axle ratio open 8 3/4", with I think 29" Diameter wheels.

A 110 LC will tend to build slightly less cyl pressure than a 112 LC, generally.
I'd think in that direction if the CR is 9.5 or more.
Lift is, within the limits of springs & architecture, kind-of free power, no driveability downside that I've seen.
Adding lift does tend to slightly increase effective duration, but in the range being considered, it shouldn't be a problem.
More exhaust duration or lift (vs. intake, aka "dual-pattern")helps with a restrictive exhaust, say full-length 2.5" or smaller duals with tailpipes.
The difference isn't huge between those 2 cams, though.
Main thing for that application is to build low-mid RPM torque, and be able to use a vac advance curve without detonation under load.
Many a wise man has stated "don't over-cam" and/or "pick the smaller one for the street", so again, the CR is part of the equation.

Good breakdown topside - I've never been a numbers guy so I appreciate the notes.

I just looked at the cam that is in my 1980 cop E58 360 in my 78 LRT. I thought it was a regrind 360 2bbl done to 68 340 4 speed spec's. It is not.

I have a Comp Cams Extreme 262/270 and it is a very good 360 cam. Not much lope on a 360, may be a bit on a 318. With my 3.55:1 gears and the stock 78 LRT's stall it gets down the road good. Not a race truck but snappy.

yup... COMP 252 and stock 360-2bbl cam almost exact carbon copies of each other.... duration and overlap, etc are identical.... I think the COMP may give you something like 0.015" more lift.... not enough to sweat over but the stock Melling 360 replacement cam is MUCH cheaper.... only without being in the "COMP cams" box.


I put one in an 83 D250 with its original (unrebuilt) 318, but I put a set of EQ heads on it with the Magnum rocker gear.... (your 69 heads had higher compression than the stock 83, 318 heads had so Mag head swap may not be applicable in your case) HUGE difference in that engine.. power and mileage both went UP. I ran a Performer (not "RPM") intake and Carterbrock 600cfm carb... this truck was 727 and 3.55s with 235/85R16s on 8 lug rims.

I also rebuilt a 69 318, and put in a 79 short bed, all stock... but bored 0.030", and a MP cam (at the time they offered the COMP 252 as a "purple shaft" MP part) and I even "chickened out" and went even smaller than a 252 (I think they had a "248" MP cam just below that 252 as well.. I was so afraid of "over camming" back then, wish I knew then what I know now) but even that truck ran freakin great.... A833 OD 4 speed with 3.91s.... I had an Edelbrock "streetmaster 318" intake on there, (it was what I could find at the local swap meet back then) and an identical Carterbrock 600 carb on it as I had on the 83.. when I had the 79, I worked at a dealer, got "employee price" on that cam or any cam I would have wanted out of the MP catalog.

That one got overloaded and USED as a truck (that thing thought it was a 1 ton) and when unloaded I ran it like a slalom toy... especially in town. 4 speed, manual steering and brakes
was the last truck I had (before my current one) that came to me with a /6..... cant believe it was nearly 30 years ago. Had that thing for 6 or 7 years, drove the wheels off of it, often with a dragging bumper (way overloaded esp for the 1/2 ton that it was)

Just putting this out there as an FYI. A 360 cam for the 1971 Dodge Challenger. Its the Stage 1 in the chart. $89.73:

https://www.rockauto.com/en/moreinfo.php?pk=8313512&cc=1496986&jsn=592

Thanks everyone. after comparing the numbers, I decided to go with Comps recommendation of the XE250H. I would rather have to up-size one day, rather than have less drive-ability. In the end, I don't think my options above were that different from each-other.

I'll let everyone know how the build goes.