Stock Cam Question

[73SwungOut]

Hi everyone. So just got my 73 Dart Swingers 318 block back from the shop. Had it bored .30 over to match the new high performance KB Pistons I bought. Had the stocked heads worked on as well (valve job..resurfaced ect.) Using Stock crank.. Will be changing the 2brl to a 4brl edelbrock..Adding an Edelbrock intake..New MSD ignition/Digital 6AL BlackBox. Currently running FlowMaster 40s (2" straight pipe) Flowtech long tube headers. Will be installing a brand new Kwik Wire 22 Circuit Wire Harness. I've pretty much reached my spending limit "FOR NOW" which leaves me with no choice but to install my original stock cam. Later down the road I will be Switching to a better Cam aswell as changing the stock Heads and more upgrades. But my question I guess would be that if using the stock cam for now...Do I still have a pretty good little set up to start for power compared to what the Swinger was originally stocked with ? Here is a Pic of my first little toys to be installed..

 

[RustyRatRod]

I like the idea, AS LONG AS that original cam has an acceptable wear pattern. As long as you run ned lifters (I would use Melling) and break it in like a new cam, it should run really well. It'll have immediate power right off idle and that will be fun. Did the shop use new valve springs?

 

[junkyardhero]

orrrr... hear me out... return the MSD **** and run stock electronic and you'll have the dough for a cam.

another option is just get a mellow cam. the summit and melling "340 grinds" are all less than $200

personally, i'd rather wait a few weeks and stack coin to knock out that key component now than tackle a cam job in situ later on down the road.

 

[RustyRatRod]

I don't know. I've always wanted to do like a 360 build. Get it up to 9.5:1, put some 2.02 and 1.60 valves in, port the heads. Give it a good loose hot ignition curve. Stock cam, 340 intake and 850 Thermoquad and some headers. Talk about a sleeper.

 

[junkyardhero]

I don't know. I've always wanted to do like a 360 build. Get it up to 9.5:1, put some 2.02 and 1.60 valves in, port the heads. Give it a good loose hot ignition curve. Stock cam, 340 intake and 850 Thermoquad and some headers. Talk about a sleeper.

when i was a broke dick teen i built up a motor like that. snagged an updated 360 short block that somebody was unloading because a cylinder had eaten a valve. the bore was still good, piston not so much. straight up trash can build, found a used piston and nabbed some rings. threw some X heads at it with a pocket port and a 3 angle and springs. nothing earth shattering. stabbed in a $100 PAW white box jobber, topped it with a weiand 8007 and TQ and went out to terrorize the town folks with a beer budget 904 build and 2.76 peg leg.

it got much better once there was a serious trans and some proper gears behind it, but still a hoot none the less. surprised a lot of people.

 

[RustyRatRod]

when i was a broke dick teen i built up a motor like that. snagged an updated 360 short block that somebody was unloading because a cylinder had eaten a valve. the bore was still good, piston not so much. straight up trash can build, found a used piston and nabbed some rings. threw some X heads at it with a pocket port and a 3 angle and springs. nothing earth shattering. stabbed in a $100 PAW white box jobber, topped it with a weiand 8007 and TQ and went out to terrorize the town folks with a beer budget 904 build and 2.76 peg leg.

it got much better once there was a serious trans and some proper gears behind it, but still a hoot none the less. surprised a lot of people.

I bet it did. I also bet it'd spin a tire bout as far as you wanted it to.

 

[junkyardhero]

I bet it did. I also bet it'd spin a tire bout as far as you wanted it to.

till the 7.25 grenaded!

a lot of people want big gnarly cams when a stock(ish) cam will suffice just fine. i put a RV cam in my 455 buick because i didn't have the doubloons for anything hi-line and that land barge would boil the hides till hell wouldn't have it.

why short change it for a few hundred bucks when it could be damn good from the jump. also, i'd rather punch myself in the groin until i pass out than do a cam (unless i'm getting paid for it).

 

[krazykuda]

What about using a stock 360 2bbl camshaft if you're going with a stock cam...

I had a conversation with Larry Shephard many decades ago and he stated that the stock 360 cam was the best for fuel economy...

I may be able to scrounge one up...

 

[AJ/FormS]

For a fun city car for myself, what I have done is;
I would run your stash except;
I would:
>use the stock cam, with 5500rpm springs, and
forgo the MSD, which is not required for this powerlevel, and forgo the long-tubes, but yes on the dual exhaust,
>and install a 2800 convertor, and
>a starter gear in the zone of 8.5>9.5 to one,
which could be any one of the following;
a) the factory A904/2.45 low,
plus 3.55s =8.70 starter, and 2600= 57mph@3%slip
b) an A998/2.74 low gear,
plus 3.23s =8.85 starter, and 2600= 63mph@3%slip
c) an A999/2.74 low, with a loc-up,
plus 3.23s =8.85 starter, and 2600= 65mph in LU
>all calcs for 27"tires)
Oh,I see you already got the MSD and headers; oh well ______________________________________________
For me;
By far, the 2800 was the best bolt-on, and gears was next best, then the 4bbl dual-exhaust.
Headers with the stock cam are optional.
With the factory Scr unchanged or as good as, I would NOT be in a hurry to up-cam.
_______________________________________________
if I ever do it again;
I am installing an overdrive, and more lower gears, my 318 loved 4.30s! (starter gear of 10.54)
Ima thinking A500/2.74 low,
Plus 3.73s =10.22 starter, and 65mph= 2080 in LU.
BadaBoom!
With this combo I would up-cam a tad and run more ScR; the reason being to run out of Second gear at 60ish mph.
That A518/3.73 combo will hit 65 at 5100@10% slip @WOT in Second gear. so Ima thinking to cam for peak power at 4800(61mph), which looks to be a cam of [email protected]. and, I'm going with Solid lifters next time.
Oh, and;
>I'm gonna put my Eddies on top with a tight Q,
> and pushing 190/200psi..... and,
>Ima targeting steady-state fuel-economy in the hi 20s.

Happy HotRodding

 

[Plymouth 65]

PM sent. 65'

 

[AJ/FormS]

What about using a stock 360 2bbl camshaft if you're going with a stock cam...

I had a conversation with Larry Shephard many decades ago and he stated that the stock 360 cam was the best for fuel economy...


View attachment 1716176226


I may be able to scrounge one up...

IDK; I wonder what Mr. Shepard was thinking.

I've run that 252* cam in a stock low-compression 318 and discovered a few things.
1) in at split overlap, the cylinder pressure drops like a stone compared to the stock cam, and
2) if I advanced it to get the pressure back, it sucked gas
3) if I retarded it to get some power extraction, well then the pressure was abysmal.
I did run that 252cam in a 318 , but it needed a 2800stall/minimum 3.23s to get moving, and of course neither of those are conducive to fuel-economy, as compared to the 240cam with a 1800/2000 and 2.76s.
I ran that 252cam with the stock 1973 convertor and 2.76s, but no way that was gonna work.
In the end I installed some 273 valve gear and played the lashing game til I was happy with the 2800/3.23s.
Here are the installed specs using the numbers from the chart, both at split overlap; the 240 cam first, which is in at 107. The 252 cam is in at 110
240int/133comp/125power/248exh/26*o-lap/47* Ica.
252int/124comp/120power/256exh/32*o-lap/56* Ica

The total of compression degrees plus power degrees, cannot be changed.
The 240cam totals 133 +125=258
The 252cam totals 124 +120=244
Let's say we retime the cam to equalize the Power Extraction at 124*, in an attempt to equalize fuel economy;
compression of the 240cam would jump to 134*, whereas compression of the 252 cam would fall to 120*. That 14* is the equivalent of about FOUR cam sizes! and explains exactly where my pressure went.
Let's say we retime the cam again, to balance the compression degrees at 132* for both, to keep the cylinder pressure equalized.
The 240 cam increases the Extraction to 126*, whereas
The 252 drops extraction to 112*, but kills the overlap in so doing.
Yes I admit;
that 126* of extraction is overkill on that 318 cam, and
that 112* is likely adequate for the 360 cam, and
that with log manifolds, overlap is relatively meaningless.
Lets say we retime both cams again to settle the Extraction at 116* which should be plenty .
The 240 cam jumps the compression to 142 degrees/Ica of 38*, whereas
The 252 cam falls to 128 degrees/Ica of 52*
The Wallace predicts the 318 to make
144psi at Ica of 38*, whereas only
131psi at Ica of 52*, again with the 13 psi...........

To make fuel economy, the engine needs BOTH pressure and Extraction. but pressure especially. Does the 318 need 258*?
At a paltry 8/1 Scr, it would seem so.
But at 9.2Scr say, I think it could get away with an awful lot less. In fact, I have proven that a 367 with Compression plus Power-extraction totaling just 227*, can make low 30s mpg with overdrive...... but the CCP was pushing 195psi.... and Power extraction was ~111*

I'm just trying to figure out what Mr. Shephard was thinking, and why whatever it was, it didn't work for me, lol..

 

[73SwungOut]

orrrr... hear me out... return the MSD **** and run stock electronic and you'll have the dough for a cam.

another option is just get a mellow cam. the summit and melling "340 grinds" are all less than $200

personally, i'd rather wait a few weeks and stack coin to knock out that key component now than tackle a cam job in situ later on down the road.

orrrr... hear me out... return the MSD **** and run stock electronic and you'll have the dough for a cam.

another option is just get a mellow cam. the summit and melling "340 grinds" are all less than $200

personally, i'd rather wait a few weeks and stack coin to knock out that key component now than tackle a cam job in situ later on down the road.

Thanx for reaching out. I really like the idea of stacking up for a cam now instead of having to reopen her again in such a short time. I'd have to buy new lifters aswell since the shop never returned them to me. So with that being said could you point me out a good cam kit that won't leave me living in a box on the street when the wifey finds out how much I spent...,"Again" LOL

 

[krazykuda]

Here's a basic list of the Chrysler factory cams and their specs:

 

[junkyardhero]

Thanx for reaching out. I really like the idea of stacking up for a cam now instead of having to reopen her again in such a short time. I'd have to buy new lifters aswell since the shop never returned them to me. So with that being said could you point me out a good cam kit that won't leave me living in a box on the street when the wifey finds out how much I spent...,"Again" LOL

1- i don't know where chuco is so i can't advise on reground cam/lifters, but if you're stateside or have that option where you are i'd give strong consideration that way, which means go get your lifters back from the machine shop.

2-https://www.summitracing.com/search/department/engines-components/section/camshafts-valvetrain/part-type/camshafts/make/dodge/engine-size/5-2l-318/engine-family/mopar-small-block-la?N=brand%3Asummit-racing_melling

that's a basic break down of the stuff from summit. if you search some of those PN's (the melling ones) you can find them cheaper elsewhere-- ebay, autozone, etx.

same goes for the melling & sealed power lifters. the only exception i know is that melling sells their basic lifter in a 4-pack super cheap. so poke around and see what you can find.

i'd probably shy away from the 484/484 cam (that seems to basically be a copy of the old MP purple shaft) and you'd want compression and a 4spd or gears w/ stall behind that.

i think the "reasonable" play would be the muscle car replacement cam 429/444 or the 444/441 "classic", or something in that range.