well here I go again.

looking in the stash of engine parts I have I noticed almost all of the early to late 80s #302 heads are very poor castings with lots of core shift and bad looking port openings. some better than others with not so rectangle openings and casting slag all over, bowls look bad with seems mid way from core shifting when cast.

the couple #714 heads are from 90-91 engines and would be the last of the pre-mag heads produced when magnum came out 92-93

the #714 casting are better looking untouched than any of the #302 I have on hand. nice bowls not much slag, better looking machine work nice even/matching size on port openings ect..

so bust them down and off to machine shop. new OEM 360 valves and bare #714 casting heads in hand. 2 weeks later I pick them up and do they look good so far.

I had them back cut the 1.88-1.60 valves the unshroud the head around the valves a little, with 3 angle on intake and 5 angles on exhaust. now to do a little clean up in the bowls and blend the machine cuts into the bowls with a gasket match to intake and headers.

cleaning up the Holley Street dominator as it works really well and has small port/runners and will add the 650DP to it.

having the block tanked-bore .060-cam bearings-installed

new OEM roller lifters/PR/rockes new set comp 901-16 springs

going with a Hughes roller cam but have not decided one which one yet.

if my math is correct this will put me at 328 CI and only 12 CI shy of 340 CI and big valves with small ports/runners should have good velocity filling the cyls.

I am looking at a SER0813ALN-14

smooth idle
high vacuum
short dur@.050
high valve lift
wide LSA 114*

will be swapping in a 833OD turning 3.23/26 tire while I am at it

oh and I cant forget to mention the HIGHLY CONTRVERSAL installing the pistons backward changing pin offset/rod angle..... yep I have done it many times.

any cam suggestions?

yes typo, sorry should be a #4 not #3 SER 0814ALN-14

I can't find that number for the cam, are you looking at the SER0814ALN-10 ?

What are your goals with this thing? Sounds like your going after a very low RPM torq motor.

you are correct Dave, low rpm torque to strong mid range 4800 5500 rpm.


after talking it over, if the heads max flow/lift is 450ish then no point in more lift than needed. so maybe a short dur and a 430/450 lift on a 114LSA.

I remember way back I use a napa brand cam with 429/444 lift in a teen I think it was a 112* or 114* they called it a MPG cam or a stock 73-340 cam?


I will look into some more cams in the 430/450 lift range.

how will a flat tappet cam vs roller cam be with the same specs? will a smaller spec roller get the same results as a bigger flat tappet???

seems I used a mopar purple shaft with the 450/455 lift range but was flat tap

numbers..why does it have to be numbers? they make my head hurt.

they say " 5 out of 4 people struggle with math "

Scratchn’s: Here are a couple pics 2 start

Very nice castings in bowl area

Had them do a throat cut and unshroud valve

Now just a light touch up on cut lines to blend the bowl

Gasket matching ports next

More

And....

Actually there is a good reason to run more lift than your heads max out at.

If you put in a .450 cam, you get max flow for the millisecond the valve stops and starts to close.

If you went with say a .500 cam you get max flow from the time the valve hits .450, goes to .500 and back to .450.

Somebody like Dewayne can perform the sorcery and witchcraft required to put the duration, LSA, lobe profiles etc where it can make the most of your cylinder heads and put the torque curve where your application needs it.

Kevin

How much did you have cut off the heads?

Agreed. As long as flow doesn't fall off at .500 then run a modern profile fast rate of lift cam to keep the valve open in the "sweet spot" as long as possible for a given duration.

Hey Scratch! I'm in the process of building a 273 for my 65 Barracuda, and will be using a set of 302 heads. Was it much of a big deal to step up the valve sizes to 1.88 - 1.60's? I'm not sure if the 273 needs that or not, but I'm open to it if it will help airflow and not hurt the velocity. It's gonna be .030 over with NORS 8.5 pistons, a D4B Edelbrock intake, MP electronic ignition. I'm using a 318 crank and bought new Scat rods cheaper than I could get the old ones redone! I'm leaning towards a Lunati retrofit hydraulic roller with 447 lift. There's another Lunati hydr roller that is slightly hotter, but I need to see what my builder says before I throw the money down. I'll be using Dougs headers in the Barracuda.
I had my 302 heads pressure checked to see if they were cracked, and they aren't. Those things are bad to crack between the valves

I have read & IIRC on a 273 and #302 heads the 1.78 valve is better as the 1.88 is shrouded and needs notches on the block cyl bores to clear. or was that a 2.02 valve?
but going bigger on the exhaust side from 1.50 to 1.60 helps it a lot. then just open/clean up bowl area, back cut valves ect.. or have them fully ported 1.78/60

how well do the #302 castings look in the bowls/port openings? last couple I had are crappy castings but my 91 #714 are pretty clean from the get go as for as casting flaws go. very little clean up and bowls are shape nicely/roundish with no big casting lines in there.

just enough to insure a flat surface.

this is why I am not just gorilla fisted hawging them out as I have in the past. I don't want to kill any flow or reshape the bowls/runners/ports very much and not get the chamber ccs mis matched. who is this Dewayne and how do you go about getting them done?

what kind of budget is needed for him to fully port them?

This is what I thought too, but an experienced head porter told me it isn't the case. He said in almost all cases once the port hits it's max flow any additional lift can cause the flow to be turbulent or stall.

From Scratchn: Gasket match.
Just clean up corners call it done.
On to block mods

It really depends on the heads, once you reach max flow there is no point opening them more, however as it was pointed out they will be open longer and the could be some benefit in higher RPM ranges but you could do the same thing with a cam that just holds the valve open instead of opening it more. Some heads will just quit flowing more if you open the valve more and not have an issue, others will actually go into turbulance and an even lower amount of flow so you could (or could not) make less power.

The 1.88 1.60 valve is only .050 closer to the cylinder wall than a 1.78 1.5 valve, if done properly this is what I would run on a 273. I would not run the 302/714 head though, I would run the 920 head from a 67 273/318, more flow and smaller chambers that better match the 273 bore. With a 302/714 head you have some chamber that does not sit right over the piston.

looking at these cams, but undecided still.

SER0814ALN-14

LSA/ICL
114*/110*

Dur@.050
208*-214*

valve lift
.500-.506


SER1418AlN-14

LSA/ICL
114*/110*

Dur@.050
214*/218*

valve lift
.500/.506


SER2226ALN-14

LSA/ICL
114*/110*

Dur@.050
.222/.226

valve lift
.515/.521

leaning toward the one in the middle.

or maybe some whimpy cams. being for a magnum engine wonder if they will work well in a pre-mag LA roller cam engine and fit my needs just as well. the 5.2 & 5.9 magnum whiplash cams work really well in the pre-mag engine. I like the HP/torque level but don't want the bumpy low vac rough idle for this daily driver.

SER9703ALN-10

LSA/ICL
110*/106*

Dur@.050
197*/203*

valve lift
.476/.485


SER9703ALN-14

LSA/ICL
114*/110*

Dur@.050
197*/203*

valve lift
.476/.485


short dur and high lift...this is more of a stock cam with more lift?

of these 2 cams I would go with the 114* LSA

still got a couple days to decide yet, pistons here this week and dropping off block for boring/cam bearings next week. this week will do the oil mods to block/main cap/oil pump. oil galley feeds to 9/32" and block/main cap/oil pump to 1/2" gasket match pump to cap-round/blends turns at oil filter passage.

lots of grinding to do.

For the most part those 114 LSA cams are going to idle pretty well with good vacuum.