yet another 318 cam thread

[volaredon]

78 Fury 2 door HT 55k original miles 2.76 rear, 904 trans. 2 bbl, still needs lean Burn to be removed. just fired it up today, fired right up. so far only mod from stock is true duals with Thrush welded mufflers (like the Flowbastards) with tails out to the bumpers. typical corner muffler shop exhaust.
I don't want to swap gears (yet anyway) (might) eventually look for a set of 3.08 or 3.21 gears for the 8-1/4.
Car is a slug off the line, absolutely loves cruising the highway at 70. will never be a race car. Not while its mine anyways. just want to wake it up a bit off the line, nothing crazy. want the wife to be able to jump in and go, kind of manners. NO, NOT going EFI. No way.
I have 2 4 bbl intakes on hand an old school 2 plane Offenhauser (have to go look for a model name or number) and a std Performer. also have a set of fresh from the machine shop, '302 heads. have a couple Carter/Edelbrock and a couple of TQs collecting dust.
the '302 heads, one of the 4 bbl intakes and carbs, and a new cam WILL be going in.
one of the AFBs is a 500 cfm. I cleaned/boiled that one some years ago, but threw it in a box. time to remember how to reassemble an AFB. as I remember it was pretty clean/ pretty good shape I also have a 600 ("625") or 2.
I will be putting a thick spacer in if I go the AFB route as the last few I ran on 318s and 360s, had fuel percolation issues while hot. maybe the Champion radiator will be enough to slow that down?

one of the TQs I have, is a 9801, with the integral built in choke. the other is a stock one for a 1980 49 state 360 (out of a Ramcharger) that I haven't used since Demon Sizzler went thru and tweaked it for me.... was meant for the Volare but it went to the attic instead. I actually have 2 of these, same carb number (don't ask me what it is right now) both got the same Demon Sizzler treatment, since at the time he was the only way I knew to get the shafts rebushed……..

already has an Edelbrock true roller chain and gears from the recent water pump replacement ( was that close, figured "might as well" do the chain) might be 8000 miles on that chain and gears. that will be staying with the engine.

I have 2 cams in mind, looking at the thread on FABO about 318 cams my head is spinning.
Im looking at a COMP 252H. (looking at its specs it is a "DEAD RINGER" for a stock 360-2 barrel cam with a whole 0.015" more lift being the only difference if you have the specs for both, side by side. this cam would be brand new (don't have it yet)

the other option I am looking at is a COMP 260H.

we're looking at doing the power tour in about 2 months and would like to do this before we go. we did the PT in this car with the existing cam it left the factory with and existing 2 bbl carb and Lean Burn back in 2009-2010. Id like to "wake it up" a little. Like I said nothing crazy.
Thoughts? am I "way off" here? would you guys use the 252, the 260 or neither?
The 260 is also used, my son ran it in his Ramcharger about 5k miles before he changed his mind and decided to go 408 and went with "whatever cam the machine shop said to"
at the time I had him pay the extra to have it Tuftrided straight from COMP, still have the lifters that were used on that cam and they are marked which lobe they came from.

would the "used but have the matching lifters" cam change anything regarding the "how to" on the break in? I have never used a used cam in a different engine than it was taken from.

 

[wyrmrider]

78 low compression 318 with tall gears and C body I'd use the Jones motorhome cam 256 with 460 lift
next best would be one of the 250-256 lunati voodoos
250 comp has much less area and 260 has too much duration and still less lift than the shorter lunati (much lesss the Jones)

 

[YY1]

@wyrmrider

Care to comment on the comp 256 vs the Lunati 256 vs the Jones?

I think that might help the plethora/paralysis syndrome most of the "stock 318 upgrade can" threads develop.

Thanks in advance.

 

[Frank Mopar]

If you want off the line power swap out the gears. Wasting money on engine mods if you don't do that first. IMHO that is.

 

[wyrmrider]

find the durations @.200
I think I have the jones and the comp but will have to get the Lunati
first post up the lifts
the comp using a design for a chevy lfter has a handicap that can't be overcome
but interesting looking

 

[volaredon]

No this is NOT A C body but a B body.
Think Rosco's cop car body. Not quite as heavy as a C would be.
Looking at what I saw of (somebody's) 256 cam it seemed kinda wild by the numbers based on (what little) I know about cam numbers. I put an erson something or other with .429/.444 lift in a 318 that was in a Cordoba back in the 80s .Lots noise, bigger turd than it had been stock

I had posted basically the same thing on FABO that wyrmrider had asked me to split off the sticky over there but being that this is a B body I thought I'd put it here too.

And I asked a mod there to do as you hadasked me to do with the thread and they came back with "it's more info and it applies so he was gonna leave it as I had originally posted it there.

 

[volaredon]

What do you mean when you say the 252 has "less area"?
Where? Less area than what? The stock cam that's in there now?
And I thought that by using the 302 heads along with the new cam would up the CR vs the stock from 1978 heads?

 

[Dodge Bros]

I think with the factory converter (pressure activated lock up???) and the highway gears that 318 car would have came with in 78 it be easy to over cam if your focus is off the line. The 252 would be better than the 260 comp. If your wanting more get up and go of the line the stock 318 cam would come of the line just as good, maybe even better than those two cams.

If you want to run the cam you have put the lifters back in matched up to the lobe they were broke in with and run it.

Going to be hard to find much performance off the line from cam bigger than stock with that gear and converter combo. A stock 1600 ish stall with the 2.7s gears kills any potential from a standing start anyway. So from that stand point I would probably use what you have, the 260 comp. My goal would be to shoot for more fun cruising after the car is rolling. Like a 45 mph kick down to first while cruising. Your kicking a dead horse off the line without gears and converter upgrades.

Some variable rate lifters like Rhoads Originals would help a little on the 260.

I would probably run the performer and that 9801 TQ. \\Edit..afb or...look for a TQ with the smaller primaries. I think the 9801 is a large primary TQ.

The 256 Jones Mopar specific cam Wrmrider mentions looks like be a good step up over those 252 and 260 comps. But if I had the 260 sitting on the shelf I would probably run it.

 

[volaredon]

no this car has no lockup it was one of the last 904s without, and one of the last that came from the factory with a converter drain plug

not saying I will "never" swap gears in the rear, just not going to do it "now"
I am looking at doing power tour this year, it seemed cool having the only car like mine on PT when I did it 10 years ago, and strangely I found myself among 3 AMC Pacers and a 69 Daytona in the little "group" I seemed to ride with, among the tons of vehicles I saw at each stop yet never seemed to see on the road.... the closest to my Fury that I saw the whole way was a 78/79 Magnum that was with the tour for 2 or 3 stops. It definitely still "turns heads" here in town as well.
If I do nothing else before PT, I HAVE TO get rid of my 13 year old tires.... would also like to replace the rear leafs and find a set of "cool" wheels to put those new tires on.... itll run as is? stock, if I have to for another year, I know.
I have most of what I am looking to put on this gar here in my attic, just the time factor.... if I "can't" use one of these 2 cams, the cam swap will have to wait til winter/ tires will have to come 1st if one of the cams I am considering absolutely "won't" work to wake this engine up. I aint looking for Hellcat power... just looking to "wake it up a little bit".


sounds like you guys that are promoting a "256" are splitting the difference between the 2 cams I am considering?
though as I remember one time looking up an "XE" 256, and it seemed a bit "wilder" than either cam I am considering?
What is the difference between the 252/260H and the "XE" series Comps?
I'm gonna have to look up some of these cams and see if I can make heads or tails out of any of them....

 

[toolmanmike]

Easy to over cam a 318. A nice dual exhaust, 4 barrel and a good ignition curve will be a great start. The 302 heads are good to raise the compression a half point or so but don't flow much more than the stock heads. The rear gear will hold you back. No reason to add components that will raise the power level to a higher rpm. The Jones cam is supposed to be a good one but I haven't heard it run or talked to people that have used it.

 

[volaredon]

I had never heard of Jones Cams til recently. I just did an online search and cannot find ANY cam profile info on them.

 

[volaredon]

Easy to over cam a 318. A nice dual exhaust, 4 barrel and a good ignition curve will be a great start. The 302 heads are good to raise the compression a half point or so but don't flow much more than the stock heads. The rear gear will hold you back. No reason to add components that will raise the power level to a higher rpm. The Jones cam is supposed to be a good one but I haven't heard it run or talked to people that have used it.

That's just it... I'm not wanting to increase power to a higher RPM, I understand quite well that would be useless. I doubt seriously I ever get this engine up to, let alone over, 4k RPM// even when when I kick it down into passing gear/ so I definitely don't want more power at 5500.... I want more power from this engine, from just off idle to say, 2800-3000 RPM, than it has now..... I remember from my 1st car a 76 Charger that also had a 318 and 2.76s that it cruised at 2K RPM about 62 MPH.... before the speed limit was 70 around here. I don't have a tach on this one but just like that Charger it seems to have a "sweet spot" around 70 MPH while cruising down the highway.
I buzz around town at 40 and below as much as I am on the highway..... THAT is the RPM range that I am looking to wake up. this car is and always will be a cruiser and that's fine.

On the TQs, I have to dig the Demon Sizzler prepped ones out of the attic, I'm 98% sure that those had the smaller primaries than the old "big block" version.... need to look at those in that respect vs the 9800 series one I have.

 

[Cranky]

Dang Don, bout time you showed up!!

 

[volaredon]

oh Ive been around...… still having withdrawls from Mopar style

 

[Dodge Bros]

256XE cam has a really aggressive 256 XE series intake profile paired up with a bigger less aggressive 268 Magnum exhuast profile. It uses the aggressive intake to build compression and the bigger lazier exhaust make a pretty broad power band. The intake profiles are harsh, and can make a lot of noise.

The 260 Hi energy won’t build as much compression or make as much HP as the the XE 256. Similar low end and mid range tq between the XE 256 and the Hi energy 260, but the XE 256 should have more peak HP. The HP on the 260 falls off fairly fast compared to than a XE256. Power band on the XE is broader. The 260 should have a lot less valve terrain noise.

 

[volaredon]

256XE cam has a really aggressive 256 XE series intake profile paired up with a bigger less aggressive 268 Magnum exhuast profile. It uses the aggressive intake to build compression and the bigger lazier exhaust make a pretty broad power band. The intake profiles are harsh, and can make a lot of noise.

The 260 Hi energy won’t build as much compression or make as much HP as the the XE 256. Similar low end and mid range tq between the XE 256 and the Hi energy 260, but the XE 256 should have more peak HP. The HP on the 260 falls off fairly fast compared to than a XE256. Power band on the XE is broader. The 260 should have a lot less valve terrain noise.

about what RPMs does that "fall off" happen with the 260?

My last cam swap to a 318, was to put in a stock 360-2 bbl cam (Melling) which, as mentioned above/ every single number for overlap, valve opening/closing degrees, centerline, was IDENTICAL to the COMP 252H.... EXCEPT the 252H had 15-thou more lift, than the stock 360 cam. and the Melling cam was 1/2 the price so for that I could "deal with" that loss of 0.015 of lift. I more than made up for that, with the Magnum head swap I also did at the same time, and the Magnum's 1.6 RR. made the lift come out to .437. that engine ran GREAT, in the D250 it was in though it had taller tires and a 3.55 gear. rest of top end was a plain std Edelbrock Performer (the magnum heads used were EQs with LA bolt pattern) and a Carter-brock 625 "AFB", Hooker Super Comps and true duals to the bumper. much better results than the Erson cam (Don't remember the numbers from it that was 30 years ago) I put in another 318 that was in a Cordoba.... lots of noise but was a complete slug.

With everything else being the same on a hypothetical engine, how much effect does rocker ratio "by itself", change the cam numbers? Duration, overlap, numbers besides lift?
I'm gonna have to check out the Lunati 256, which has been mentioned a bunch. I have never used anything from Lunati before. like I said...baby steps. I don't drive this car much, usually 2-3 k a year average and only in nice weather.

I appreciate the suggestions provided here, sorry for the stupid questions/ Ive rebuilt engines before, usually back to stock or very close to it.... I understand the mechanics of the engine, but when I get into breaking down cam numbers, I get dizzy looking at all the numbers/ and finish, more confused than I started.
and no I'm not "stuck" using one of these cams just because I have them... but just trying to understand why either would/wouldn't work for what I want,
not looking to "cheap out" or brag because I spent a ton.... I want bang for the buck, and NOT to have to swap the cam more than once, its is a fair amount of work, that Id rather not have to repeat on the same engine, more than once.

 

[Dodge Bros]

In the cam range your looking at, bang for the buck is very likely going to be a cam designed for a Mopar lifter diameter from Howards or Lunati.

You can’t really compare the seat timings of a Melling to a Compcams becuase the Melling cam uses SAE ratings on all their cams and Compcams rates their cams at .006 at the tappet. SAE ratings are durations measured out at the valve at .006 lift. With a 1.5 rocker it is the equivalent of a .004 tappet rating. The rocker arm ratio effects that rating. If the engine is say a ford that runs a 1.73 rocker arm the extra seat timing from the rocker arms shows up in the rating. From a 1.5 rocker arm a 1.6 rocker arm usually adds about 2 degrees of seat timing and 3 to 4 degrees at .050”. Melling cam you had was also likely was also a symmetrical grind, opening and closing ramps are the same. I could probably come close to what the similar .006 tappet lift rating if I new which cam it was.

The 250 & 260Hi energy, and the XE’s are asymmetrical grinds, more aggressive on the opening ramp, less aggressive on the closing side. Each series has different accelerations as well. There are more difference between each cam than just the lift or seat timing.

I think in a 318 the 260 comp will probably make it to about 5000 before you really notice the power falling off, peak power just before 5k.

 

[toolmanmike]

There are no magic bullets for stock 318's. Changing cams are quite a job when the one you're putting in isn't much difference than the stock one. Just like the heads. Not enough difference to justify a swap. Now if you are building a engine That's a bit different. Usually you build for bigger horsepower numbers. That comes with a trade off though. You loose bottom end. (Where you spend most of your time) And you need headers, modified stock or aluminum heads, big intake and carb, converter, and high ratio gears to make that big cam work. Tune what you have and go from there. Then my next step would be gears. 3.21 would be better. A 3.54(?) would be better yet..

 

[volaredon]

I'm not going to put an od trans in, so I didn't think I'd want that much gear.
On what you say about the cams I am looking at, I don't believe the 252 or the 260 are assymetrical. I was looking around jegs between posts here and they each have the same duration on intake and exhaust. Where this 256 people are talking about, don't.
I do see that in looking at the numbers this time it seems like nobody wants to tell you everything you need.
Before when I would do a cam swap the manufacturers would tell things like valve opening and closing in relation to tdc/bdc, I don't see it listed anywhere any more.
I know that when I put that melling stock replacement in my truck they did/ though that was about 10 years ago. Which I had compared to what the factory service manual had said and what comp said about the 252 at the time
These cams I was considering are "252 H" and "260 H" not the xe series like the 256 if that makes a difference.
And if hp drops at 5000 then I will never see it drop off as I am sure this engine has never seen it anyway.
Still just trying to understand the "numbers" related to the cams.

In my daily driver Dakotas, which all have had a factory tach I know that I don't see that kind of rpm, with 3.55/3.91 gears
I think I took the rpms to that level maybe twice in the 55k miles I have owned the 96 Dakota, just screwing around/ but normally don't come close to that level. And that one has the 3.91s.

 

[Dodge Bros]

I think you might be confusing the term single pattern cam and symmetrical.

Single pattern has the same lobe on the intake and exhaust (260 hi energy intake, 260 hi enter gt exhuast).

Split pattern cam has a bigger profile on the exhuast (XE256 intake, 268 magnum exhuast).

Symmetrical describes to lobes themselves (Melling, summits, white box 204/214,224 cams ect. opening rate and closing rate are the same, but the cam be single pattern or split (sometimes also called a dual) pattern cam, they have more duration, bigger profiles on the exhaust.


The Hi energy cams are single pattern asymmetrical grinds. Melling grind you had was a single pattern symmetrical grind.

For some perspective, we had a 72 B body with a stock 318, a set of headers and 4 bbl woke the car up quite a bit. It had headers, stock cam, a performer 4 bbl, 600 holley and 2.71 gears. The factory stall flashed to 2200 though, that really helped. I think it ran about a low 16 second et @ 85 mph in the quarter. We later used a 214/224 cam with 3.23s and it would run 15.5-15.6 et at 90-91 mph with a smaller thermoquad.