318 Head Opinions

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flyboy01 said:
I have actually run my above combo in a Dakota a few years back and I had no complaints about torque or HP, top end was great, but I had FI, 4.11 gears, and a 5 speed. .


flyboy,
What was you first gear ratio? And then all the rest? For each gear. See you have to add this gearing to the rear gears per gear to get a true ratio for first gear,and the gears after. Then what gear did you go through the traps in? Add this to the 4.11 gear and now you have a total rear gear. Also FI helps low end performance and torque.
 
BJR, just out of curiosity, what kind of air speeds do you get from these 302s? Over 300? between 250 and 300? Have you ever had a set wet flowed to see what the fuel is doing at that speed? Any burn patterns on the pistons? If it's all Code 5 super secret, just say so...
 
Moper,
The air speed is over 300 and is dry flowed, but as you know the air speed will change with rpm's, and is over 200 @ 3000 rpms. I haven't had a set wet flowed, and I know this will change the velocity some. And yes the fuel will do strange things when high velocity is present, but there are some things that can be done to help correct this and help to keep this from happening. Most all the burn patterns on our engines completely cover the top of the pistons, but this has to do with piston and chamber shapes. And I'll leave it at that.
Geeeessssss you want me to tell you everything? I DON'T THINK SO.
 
Nope..Just wanted to know if you were having to make changes to keep it from flying out...lol. I was more concerned with the test pressure's velocity. But if you're flowing over 300 at 28", that tells me enough. Besides, I said "feel free to just tell me if it's secret stuff." I know how you guys are ;)
 
So, my stock police interceptor 318 ELE short block w/j-heads probably will be doggish off the line? I'll tell you tomorrow! It has an A-999 wide ratio w/lockup and what ever the factory put in /6 barracuda's in 1968 for a rear end. Eddie intake and carb, factory 318 exhaust manifolds w/dual 2 1/2's and flowmaster 40's. Let's see what happens!!
 
Well, here you go. I may not be clocking any record breaking 60 foot times, but this thing is not, NOT most definitely NOT a dog down low, it begins to wake up as soon as I touch it, and although a gear change out back will improve it, I was suprised by the torque. I suppose it has alot to do with the dual plane/cam/factory exhaust manifold combo, but it pulls strong. I learned that I have a 7 1/4" rear end, and that will be on of the first changes I plan to make, a spring relocation kit and an 8 3/4 are at the top of my list. 3.55's and a sure grip unit are the ones for me. I also learned that the 999 tranny is a NON lock-up version, so I can use 904/998 parts w/ no problems (whew!), and I am stoked about that. But other than that, for street use, my friend, J-heads on a 318 are working well in my particular application, and that is a fact! Good luck!
 
What kindof 60' times did you have? What did it do before you made the change? Or changes? Just courious as I know what happend to our times, but our setup is a good bit different than yours, but a change is still a change.
Also how much cylinder pressure do you have psi? 120-150-170? What did you have to start with?
 
Im going with magnums.I'll tell you why.

Drop them on your stock 318 short block and you have roughly 9.1:1 compressionUse an .028 head gasket and you have roughly 9.3:1.

Offset grind the crankshaft(Im doing this) and you could bring the pistons up say another .015 to .020 .Compression is now around 9.7 to 9.9:1.And have a few extra cubes as well.

The 302's need a lot of porting to even come close to a magnum.And then when the mag is ported,they leave the 302 behind.

Have the mags drilled and tapped for an la intake or buy a mag specific intake.Either way,no big deal.

As for cracked heads,well all heads crack.The lean burn year heads were prone to this too.It's not a mag specific thing.Chev heads of that era had cracking problems too.Dont know about the fords.Everyone makes a big deal about this cracking thing.I dont know why.It's very easily repaired to better than new status.Ask your engine guy about a process called pinning.That will fix it.
 
I like the Magnum heads for certain build up as well. The stock head off a "LA" isn't to bad and easy to up grade. It becomes a catch 22 at this point. Sometimes it is worse when someone allready has a cam with alot of lift that the change to a Magnum hed can not be done as cheaply as off the J-yard car onto his engine without added expense.

The 302 is a nice head that ports out very well. If you all ready had a set or acquire a set cheaply, then it could pay off easy to port them rather than going toa Magnum head and added expense of acco. parts of the swap.

The price of porting a set or 302's vs the Magnum swap and possible cam change is a pesonal call at this point. If the 302 is in good shape, the porting price is about the same as the Magnum head/cam swap.

I agree on the cracking. If it ran lean to long or hot to long, cracks will be there. The are also not the end all.
 
As for cost maybe I got lucky.I think it was partly being patient and waiting for the deals.

Rebuilt mags;$500 complete with new springs/seals/valvetrain/rockers etc, valve job and milled!
M1 intake off ebay;$105
Head bolts;$55
Mag valve covers;$15(not essential,but I like em)
MP pushrods;$65
Porting templates;$15(again not essential,but I wanted em!)
Cam and lifters have yet to be purchased..
Grand total;$755

I know guys who have more than this in thier la heads alone trying to get the same breathing.Yes they will achieve higher peak numbers,but never the same under the curve.Hemi guys can relate to what Im talking about.It's the reason chevie lost time and time again..

And thats the beauty of the mag.It's not a hi flow head.The ports arent huge.It's a hi velocity head.Works better down low than the la and better than the 302 up md -hi.Plus the exhaust ports are much better.Relates to better scavenging and more vacuum,thus better mileage.The heart shaped chamber is more compatible with todays fuel and resists pinging.Better efficiency for more complete burning.They also seem happier with less total timing advance.

I also would suggest that if there are guys who have killed the bottom end torque on a teen using mags;be more conservative with your cam selection.A teen reacts different than a 360 to the same cam.It "sees" more cam due to less displacement. Also, most bigger cams sacrifice bottom end torque for hi end power.Not to mention need much lower gears and loose convertors.So a cam with .480 lift in a teen is quite a large cam,but not so with a 360.The smaller bore may contribute to this.So for a teen,less is more.

I also wonder why no one uses offset grinding to bring compression up anymore?This is an old timers trick.Kind of kills 2 birds with one stone as the stock pistons can be reused,thus balancing is not essential(allthough I'll still do it).Just be sure to check piston/valve clearance!

I'll get off my soapbox now...
 
I never seen or heard of many people at all doing the off set grinding crank trick. Theres actually a thread here on doing just that somewhere.

Theres also a few on stroker on the cheap. Reuseing stock pistons in such applications as well.

So a cam with .480 lift in a teen is quite a large cam,but not so with a 360.The smaller bore may contribute to this.So for a teen,less is more.

I'm not so worried about the bore size or valve shrouding but the cam size is fairly moderate large size for the teen. I had an arguement with a fella once on this were I didn't really like this cam in a teen with his proposed 3.55's. I thought it to steep. Even with a converter to help it out alot, his balance was off and ears closed.

Stock Magnums do not flow so great. Not bad, but not great. $500 for a rebuilt set is OK and nothing I would jump about. X and J heads are also found rebuilt for this and port well also. Granted, not as good as the Magnum, but the additinal cost of converion hinders most.
Ya kind of gotta want to do it. As much as I could point to this head being better, for some people, an extra 1 or 2 hundered is alot. Therein is the reason for building what you got.
 
I'd like to hear more about offset grinding a crank to raise the pistons .020. My quick math tells me you would need a set of .040 undersize rod bearings and a crank which shows absolutely no wear on the outermost area of the rod journal.
 
Well, just to let you guys know, I went ahead and bought a freshened set of 302s. I'm presently doing a gasket match and some minor home porting. To me this is the best bang for the buck. I also purchased Comp XE268(with gear,chain,lifters,etc), thin MP head gaskets, and Spitfire headers. As stated earlier, this car is for the street with possibly a rare trip to drags. I think this combo should run strong with the 4spd, 3.91s. Thanks again for all everyones help. I'll let you know how it runs. Mike
 
I'm staying tuned Mike. Waiting to hear from you.

Cheif, I think it is just a matter of being creative. Perhaps creative use of a 360 crank and a lower comp. ratio than stock piston? I don't know, but possiblitys are out there. Offset grinding .020 is 2 cubes? Plus this in a .060 teen and it's a 330.

My 400 has the slugs in the hole .120. Off set gind with Chevy rods? Increase the stoke by ????? Add ?????
.102 is a 414 cid and @ .030 overbore, it's a 420, .060 is a 426.1.

I think hot rod did a Mopar like this not to long ago. On a 440 i think. It just hit me. Anybody see that?
This would actually make a good thread on it's own.
 
Totally understand using what ya got.But I thought he was buying heads...

Yup,$500 for the heads was O.K,not excellent.But they are crack free and ready to run!!

I think you can get .040 undersize bearings for a teen.Maybe just .030.I swear I saw .040 somwhere...

Not sure how much it's realistic to expect the pistons to come up with offset grinding.Think I'll give my machinist a call
 
Just did a quick check on Summit.There is an .040 undersize rod bearing.So working on the assumption that some material has to come off the top side as well,suppose I assume a .015 increase in stroke with offset grinding.This brings the pistons up .015 as well,thus more compression.With stroke going to 3.463 and a .040 over bore on the block,cubic inches end up at....339.5 c.i,or a 340 if you like.

Now,using a Mr gasket head gasket with .028 crush thickness,4.14 bore,64 cc magnum chambers and pistons at .045 down in the bore,compression comes out at 9.78:1.With the right head work and cam,400+ ft/lbs of torque would be achievable.

Thats what Im shooting for.Lots of gut wrenching torque as I've got a fairly heavy cop car(3800lbs) to motivate,plus 2:94 sure grip out back.

Im looking at a comp cam dual energy grind.CRS 255 DEH-10.Might be kinda mild to you but the 1.6 rocker ratio gives a bit more lift(.471 .492)
 
has anyone used a set of eddy heads on a 318? results? i am considering a head swap on my 318 in a 69 cuda.
 
BJR Racing said:
The actual stroke will be 3.325 with a .015 offset grind on it.


OOOPS!!!!!Must have missed that pesky zero.You are absolutely right of course...

That invaladates my math.

Total cid is now 326 and compression 9.44:1.

Thanks for catching my math mistake BJR.I am prone to that after 11:30 p.m ... :)

Just out of interest,with a max overbore of .060,cubes come up to 330, and compression to 9.5:1.I probably wouldn't bother boring this much as I think the cylinder walls might loose too much integrity and tend to go out of round at higher rpms.Opinions??Maybe this wont happen unless the bore is crazy bored out to 4.00??What is the max overbore for a teen with the cylinder still retaining it's structural integrity?
 
Still sounds like a lot of extra expense (unless your crank shop is cheaper than the one I go to). So if you want a torque monster, why not just start with a 360? Using the same parts, you WILL NOT make more torque with a 318. Never. Period.
 
C130 Chief said:
Still sounds like a lot of extra expense (unless your crank shop is cheaper than the one I go to). So if you want a torque monster, why not just start with a 360? Using the same parts, you WILL NOT make more torque with a 318. Never. Period.

Very true.And it so happens that I have a 79 360 4 bbl kicking around.BUT,it's earmarked for my 70 Dart.

The cop car has a 318 4 bbl in it,and it will stay there until sold and someone else can drop a 360 in it.

Do you think offset grinding is more expensive than regular crank grinding?

Seems to me the setup time for either would be roughly the same...

And yes,the machinist I know owns all his own equipment and a shop on his own land,plus does all the work himself.Low overhead gets passed along to me!

And no,there are no quality issues.Several friends have had engines done by him,with excellent results.
 
Look in Mopar Collectors Guide:

Magnum heads - AS CAST LA Intake pattern 60CC Chambers 235 at .500 out of the box $439.00 just add valves and springs.

You can't successfully redrill a Magnum head to LA Pattern, 90% of all Factory Magnum head cores are cracked.

http://www.4secondsflat.com/FBo_EQ Cylinder heads.htm

Just buy the new castings
 
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