'68 318 to carbed Magnum 5.2: Check my checklist

[txstang84]

There's some debate about that since the magnums use TTY head bolts...I say no, others say yes...the new bolts for magnum heads are only $35 a set...but I'm not going to argue that **** again...especially online. Do the research, make your choice.

 

[txstang84]

...otherwise, yes, a 5.2 mag would be a good source for the parts.

 

[cudak888]

There's some debate about that since the magnums use TTY head bolts...I say no, others say yes...the new bolts for magnum heads are only $35 a set...but I'm not going to argue that **** again...especially online. Do the research, make your choice.

I can hack $35 for head bolts, no problem. At least it feels like a much better value than $32 for exhaust manifold bolts.

Some really good deals on eBay for Magnum heads; better than I can do at the junkyard - and I can always rip the rockers and pushrods out of a couple of 3.9s, which are ever more plentiful.

-Kurt

 

[txstang84]

Again, do your research-there are some folks on here who've had issues with eBay sourced heads--caveat emptor and all...

 

[cudak888]

Again, do your research-there are some folks on here who've had issues with eBay sourced heads--caveat emptor and all...

Ooh. More stuff to Google. Time to peel out my search bar again :burnout:

-Kurt

 

[txstang84]

Just look in here...

 

[cudak888]

Just look in here...

Doing so right now - "site:forabodiesonly.com magnum heads ebay"

Haven't found anything yet. Will keep looking a bit later.

-Kurt

 

[cudak888]

Well, can only find info on the usual cracked Magnum heads; nothing else - unless I'm missing some key word in a post title or discussion.

-Kurt

 

[txstang84]

Probably using too specific of search terms...what I meant was use the search function in these forums for "ebay heads" or something simpler. Yes, it will create more hits to sift througg, but at least there's more info.

 

[cudak888]

Probably using too specific of search terms...what I meant was use the search function in these forums for "ebay heads" or something simpler. Yes, it will create more hits to sift througg, but at least there's more info.

Well, looked around all over last night and never quite found it. I'll try the junkyard first, then move on to the Wild West of the internet.

I'd really love to put a set of EngineQuest Magnum heads on it, but not at the cost of the heads + a three-angle valve job by the local shop.

-Kurt

 

[Infecteddog]

Now. I'd think your compression w/stock heads should be around 8.2-8.4:1. I've heard of LA rollers having stock oil-thrus before. Magnum heads should bring it to right around 8.8:1.

While the Magnum pistons were different- I think they were functionally the same and without the heads would not improve the CR anyway like the old 318s where the CR bump happened not from same size closed chambers but from new pistons.

Not that much of a problem. There's the Chinese Crosswisefartwind intake, of which a new one will cost no more than the Edelbrock Performer 318/360 that I have now. With a bit of fancy eBaying, I should be able to turn one into the other.

Are the head bolts on a Magnum head reusable like the LAs? If so, I might be able to dig up a Magnum 318 at the junkyard with good heads, bolts, pushrods, and the rest of the kaboodle.

-Kurt

Most say they're TTY and not reusable so I can't suggest what I did.

We redrilled my heads for the LA pattern- course ended up going back to a Magnum intake in the end.

 

[txstang84]

I thought about suggesting you buy a set of EQs, but I'm under the impression you're trying to save pennies where you can. Keep in mind, many magnums (as you've found already from searing on google) suffer from head cracks...I'm pretty sure the heads on my 5.2 are, since the donor '98 Dakota had over 200K miles on it

 

[cudak888]

Now. I'd think your compression w/stock heads should be around 8.2-8.4:1. I've heard of LA rollers having stock oil-thrus before. Magnum heads should bring it to right around 8.8:1.

While the Magnum pistons were different- I think they were functionally the same and without the heads would not improve the CR anyway like the old 318s where the CR bump happened not from same size closed chambers but from new pistons.

Most say they're TTY and not reusable so I can't suggest what I did.

We redrilled my heads for the LA pattern- course ended up going back to a Magnum intake in the end.

Out of curiosity, which specs gave you those much nicer numbers? 0.040 in the hole? At any rate, it would be very nice if these specs are indeed correct.

I see your point about the Mag pistons (particularly as they're dished - just with the dish spread side-to-side as opposed to circular), but are they really as deep as those in this 360? Somewhere I read that the heavy-duty 360s had slightly lower compression to prevent predetonation from harsh acceleration with a heavy load.

I don't know how accurate this is, but it might explain the difference between our numbers.

I thought about suggesting you buy a set of EQs, but I'm under the impression you're trying to save pennies where you can. Keep in mind, many magnums (as you've found already from searing on google) suffer from head cracks...I'm pretty sure the heads on my 5.2 are, since the donor '98 Dakota had over 200K miles on it

True, saving as much as possible is preferable, but sometimes the sensible decision may be to spend a bit more.

I could wind up spending over half the cost of a pair of loaded EQ heads ($504/ea @ JEGS) trying to get a pair of junkyard units presentable, and still not get away from the factory crack issue (I know it's a non-issue, but still), nor have ports that are cast as nice as the EQ's.

Plus, if I do the CH318B heads, I get the LA bolt pattern with no further effort required. Thus, no need to go through another intake sale and purchase.

Perfect example: This LA 360 looks as if it'll wind up costing me the same as a Magnum 5.9 longblock at the end of the day, even though it seemed cheaper to begin with. Yet, I could have gone the route of a $1,700 Mag block and saved myself some effort for a better result. But I'm in the soup now, and I'm going to stick with it.

-Kurt

 

[txstang84]

Good point, but pretty much any set of heads will benefit from inspection and cleaning. Magnum heads probably would work out well if you plan to keep the roller cam...just some food for thought here, you could get it reground from Oregon for $125...put a little extra oomph in it.

 

[cudak888]

Good point, but pretty much any set of heads will benefit from inspection and cleaning. Magnum heads probably would work out well if you plan to keep the roller cam...just some food for thought here, you could get it reground from Oregon for $125...put a little extra oomph in it.

Inspection and cleaning are cheap. It's the problems you have to fix on a 200,000+ mile head that starts a a quick rate of negative cash flow and time spent. I'd rather eBay my way silly to increase the old engine parts fund and buy the EQ's straight off. Arrives in the mail within a week, bolts directly onto a clean deck surface, and that's it!

Roller cam and lifters stay right where they are. No change there. Not going to screw with the cam either - I'd rather not have to worry about any break-in procedure on startup (I believe in breaking in roller cams too).

-Kurt

 

[txstang84]

No argument about the heads-I was only saying that having the new heads inspected for proper installed height, guide tolerance, checking the seats, plus a decent cleaning would be advisable. As far as breaking in a roller cam...it's not needed. The whole purpose of breaking in a flat tappet cam is to work harden the face of the lobe and lifter to one another so they don't dig in. With stock spec roller cams, this process is unneeded due to the hardness of the lobe material and the roller on the lifter. They don't need to be, nor is there any value added (for the cam) by following the break in steps for a flat tappet cam. Now, that being said, if you replace the rings and recondition the cylinders, they'll need to be broken in and proper ring break involves varying the manifold vacuum and engine loading at varied RPMs...which is why many engine builders like to break in engines on dynos because they can vary the load placed on the engine. What I used to do with roller cam engines after making sure there were no fuel/oil/coolant leaks would be to have a friend ride with me and drive around town up and down hills...seemed to work well for the ones I had part in building.

 

[cudak888]

Possible slight change of plans:

Found a pair of perfect Magnum 5.9 heads on Craigslist for dirt cheap from a fellow who swapped to cast-iron R/T heads. They've been very mildly surfaced too; not enough to affect intake fit.

Seems like a no-brainer, though that leaves me with the question of the intake. The super-expensive Edelbrock intakes have a Magnum-style outlet, shifted to the passenger side. The Crosswind is a centered LA outlet.

Either of these is a no-go with the 1988 brackets, but Bouchillon offers brackets compatible for one style or another which retains the V-belt setup.

Now the big question though: Should I consider the vertical-bolt Chinese intake, or go punch-drunk crazy and attempt to drill the 83 degree holes in the Magnum heads on my friend's Bridgeport mill so I can use my Eddy Performer 318/360?

-Kurt

 

[txstang84]

Possible slight change of plans:

Found a pair of perfect Magnum 5.9 heads on Craigslist for dirt cheap from a fellow who swapped to cast-iron R/T heads. They've been very mildly surfaced too; not enough to affect intake fit.

Seems like a no-brainer, though that leaves me with the question of the intake. The super-expensive Edelbrock intakes have a Magnum-style outlet, shifted to the passenger side. The Crosswind is a centered LA outlet.

Either of these is a no-go with the 1988 brackets, but Bouchillon offers brackets compatible for one style or another which retains the V-belt setup.

Now the big question though: Should I consider the vertical-bolt Chinese intake, or go punch-drunk crazy and attempt to drill the 83 degree holes in the Magnum heads on my friend's Bridgeport mill so I can use my Eddy Performer 318/360?

-Kurt

Hmm...

Has anything else been done to them aside from surfacing? If that's all that's been done then you're really only about $100-$125 ahead...if they've been fully reconditioned though, you may have a good deal. That being said, if you have the means and capability I'd say go for the machining and LA style intake. I have the edelbrock , magnum intake, and I've used the crosswind intake. It does work and fits correctly, just gotta make sure it's straight. The intake is a decent choice though.

 

[Abodybomber]

Well, looked around all over last night and never quite found it. I'll try the junkyard first, then move on to the Wild West of the internet.

I'd really love to put a set of EngineQuest Magnum heads on it, but not at the cost of the heads + a three-angle valve job by the local shop.

-Kurt

My take,my experience's
Buy a set,lap in the valves ( turned down,possibly new..) .. The out of the box valve job, is good for basic horsepower work.. I did this on mine : Bare E.Q castings, added S.I stock replacement valves/Hughes 1110 springs,( BIG cam for your setup) Buy a set, turn /check the valves ( have the out of round ones ,replaced /resurfaced) .If using a stock can, use new stock springs. The difference between stock worn heads, & out of the box E.Q. heads: Nite & day... They aren't race car perfect, they are really nice on basic builds, out of the box... The " basic valve job" is just fine, spend more moohlah for real horsepower.

 

[Abodybomber]

Hmm...

Has anything else been done to them aside from surfacing? If that's all that's been done then you're really only about $100-$125 ahead...if they've been fully reconditioned though, you may have a good deal. That being said, if you have the means and capability I'd say go for the machining and LA style intake. I have the edelbrock , magnum intake, and I've used the crosswind intake. It does work and fits correctly, just gotta make sure it's straight. The intake is a decent choice though.

I didn't even read this post, before above .. Have had both carbed intakes, both are good. If so, on the stockie Magnum heads: Nice find. Check 'em out, & get it if good.

 

[cudak888]

Hmm...

Has anything else been done to them aside from surfacing? If that's all that's been done then you're really only about $100-$125 ahead...if they've been fully reconditioned though, you may have a good deal. That being said, if you have the means and capability I'd say go for the machining and LA style intake. I have the edelbrock , magnum intake, and I've used the crosswind intake. It does work and fits correctly, just gotta make sure it's straight. The intake is a decent choice though.

My take,my experience's
Buy a set,lap in the valves ( turned down,possibly new..) .. The out of the box valve job, is good for basic horsepower work.. I did this on mine : Bare E.Q castings, added S.I stock replacement valves/Hughes 1110 springs,( BIG cam for your setup) Buy a set, turn /check the valves ( have the out of round ones ,replaced /resurfaced) .If using a stock can, use new stock springs. The difference between stock worn heads, & out of the box E.Q. heads: Nite & day... They aren't race car perfect, they are really nice on basic builds, out of the box... The " basic valve job" is just fine, spend more moohlah for real horsepower.

Not sure if he's done a three-angle job on it; possibly, as he was hot-rodding the 5.9 in his Dakota R/T. They may be the stock valves relapped. Heads are all of $300 and said to seal perfectly at the valves. Mineral spirits down each port ought to confirm that quickly. If so, I see it as being $700 ahead.

Might as well just use the Crosswind and sell the Edelbrock. Small price to pay.

If I stuff any more power under this hood, I'll guarantee myself an eaten-up 904.

-Kurt

 

[cudak888]

A bit of progress tonight. Opened up my Fel-Pro master gasket set, only to find the timing cover gasket broken:

Went out and bought a Magnum-type aluminum core gasket to replace it with. Nice thing too, as the Magnum gasket does away with the extra bolt hole that the standard gasket provides for the poly-head 318s.

Got the pan on with the Fel-Pro 4-piece pan gasket. Didn't go on too neatly (my love for The Right Stuff as an RTV substitute and gasket shellac has something to do with this), but I don't expect it to leak either:

I might give the bottom half a bit of paint so I can get the front seal and harmonic balancer on, but I'm pretty much going to wait for the heads now before doing anything else.

-Kurt

 

[txstang84]

Not sure if he's done a three-angle job on it; possibly, as he was hot-rodding the 5.9 in his Dakota R/T. They may be the stock valves relapped. Heads are all of $300 and said to seal perfectly at the valves. Mineral spirits down each port ought to confirm that quickly. If so, I see it as being $700 ahead.

Might as well just use the Crosswind and sell the Edelbrock. Small price to pay.

If I stuff any more power under this hood, I'll guarantee myself an eaten-up 904.

-Kurt

Gotta ask, as none of us are there to verify the condition. Tim is correct though, you could lap in some new valves, install good springs and be done. The reason I'm a little skeptical is simply because used heads are just that, used. If in the event the guides are worn out of spec, and valves are equally worn, springs not springing...you get the idea, that's why I brought up that you may not be ahead excepting the cost of surface machining. I've bought many used parts...some in near new shape, others nearly dead...your , mileage may vary.

As far as your 904 being eaten up behind a near stock 360, I will say there's no better time to do a rebuild than when the engine is out.

 

[cudak888]

Gotta ask, as none of us are there to verify the condition. Tim is correct though, you could lap in some new valves, install good springs and be done. The reason I'm a little skeptical is simply because used heads are just that, used. If in the event the guides are worn out of spec, and valves are equally worn, springs not springing...you get the idea, that's why I brought up that you may not be ahead excepting the cost of surface machining. I've bought many used parts...some in near new shape, others nearly dead...your , mileage may vary.

As far as your 904 being eaten up behind a near stock 360, I will say there's no better time to do a rebuild than when the engine is out.

Supposedly 95k on these heads overall. I'll bring my spring compressor when I go to see them; that'll give me an opportunity to check valve guide wear.

A shame the 308 head springs don't swap over; everything points to them being virtually new (though I will admit that it's more or less impossible to say for sure).

I'll jump the creek of the 904 when it eats itself up - if it does. For all I know, it might be in good shape.

-Kurt

 

[cudak888]

Did some asking. Stock valves, light surfacing on heads.

At this point, I'll be content with a home-done valve lapping job if the valves are tight in their guides.

I also have this coming week off, so I might go punch-drunk and try drilling these heads for the LA bolt pattern on my friends Bridgeport mill, rather than order and wait for a Crosswind intake to arrive.

Frankly, I hate the idea of the cheap Chinese casting to begin with, so I'm not that against the idea of drilling the heads.

-Kurt