1985-318 or 1976-360 for PU?

http://hometown.aol.com/russjerome/images/jan08plow.jpg
My 1985 3/4 ton plow truck with the little 318 needs to get pulled for
a rusty oil pan and will probably swap out cam/lifters. Since I need to
pull the motor for the pan I was thinking about swapping a 1976 360,
I have with a similar 100k mile running camper (4 barrel). My 318 4v
runs great with its GM HEI ignition swap, gets maybe 14 mpg and
will double as my tow vehicle soon. The camper will get scrapped.

Is the low end of the 360 gonna be enough to make me happy I went thru
the effort of a swap (I store the camper 50 miles away....fuel) or will I
be just as happy with the 318 after a cam/headers/carb?????????
Both have good comp, both need to be resealed.

ps: I know about the balance issues and motor mounts, just unsure
of real world difference between 42 extra cubes in a truck.

IMO, it's worth it. Both engines are very strong low-end performers...their listed torque peaks are both 1600-1800rpm lol, diesel like. The 4bbl teen is quoted at 240 ft-lbs (160hp) and the 360 is 270 ft-lbs (180hp) from that era. I've experienced the swap before b/w a two barrel 318 and a stock-ish 4 bbl 360 before in a car, and it was a noticeable improvement.

But I do assume your 'teen came from the factory with the four barrel? If so, it's a better 318 than most and uses the improved 360 heads/cam already, so all you'll gain is a little more compression and cubic inches if just doing a straight up swap. If pulling the engines anyway, then why not do it for that reason alone?

I don't know what your thoughts of the 'teen now, but if you are satisfied, the 360 won't diminish it, that's for sure. If you are left wanting more, then I'd make sure I got what I wanted from the 360 while I had it out.

A few mods I'd probably invest in:

Of course, all new gaskets.

I'd mill the heads 0.040 to bump the compression up a tad, even with the thicker than stock replacement gasket. Could probably go as much as .060 down provided you use a typical fel-pro head gasket (as the stock one is a bit thinner) and not need to mill the intake surface or shim the rocker arms up.

I'd upgrade the camshaft with the small summit camshaft. 204/212 @ .050 .420/.444 lift would represent a healthy step up from the stock 360 cam. You shouldn't need upgraded valve springs to accommodate the new cam either. You won't lose any low-end really, but gain a substantial amount of torque in the mid-range. Of course, get the double roller timing chain too.

You should be able to use your intake/carb from the current 'teen. That HEI ignition will be a big asset as well. Headers makes a HUGE difference on these trucks.

With that, you should be pretty happy with the outcome. It's the same basic recipe that my coronet is using (albeit, I have the stock small valve/port 318, and no milling to bump up the compression) and I am VERY happy with the tired 'teen. Ran a 15.2 @ 92 mph with stock converter and 2.76 hwy gears...a decent compression 360 and that combo would be quite stout.

Knowing that you'll need the correct flex plate makes life easier. For the engine mount, the stock 'teen ones are actually fine. All you need to do is use a handful of washers to shim it up on the driver side. Worked fine on the valiant.

Quote:

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Originally Posted by Prince Valiant

But I do assume your 'teen came from the factory with the four barrel? If so, it's a better 318 than most and uses the improved 360 heads/cam already, so all you'll gain is a little more compression and cubic inches if just doing a straight up swap. If pulling the engines anyway, then why not do it for that reason alone?

I don't know what your thoughts of the 'teen now, but if you are satisfied, the 360 won't diminish it.

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The 318 in the 1985 plow truck is originaly a 2 barrel motor, I quickly
swapped out the feedback for a quadrajet (im a longtime chevy guy)
and HEI, like a new vehicle I have no complaints about the 318 otherwise.

But as a plow vehicle the only thing that stops this truck is power down
low, I can push snow without traction issues until I finaly put the 318
up against the convertor and its all over. This will be my tow vehicle
with trailer/car to Cincinati next year, gonna freshen up whatever I
put in (had an old L-78 396 in my garage I gave away yrs ago, wish
I still had it).

The 360 swap looks great to me on paper, there just seamed to be
so many 318 loyalist who would rather cut off there $%# before
swapping for some reason. Im leaning towards it the more I read.
I need to move this RV off the inlaws lawn anyway.

Quote:

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Originally Posted by Russ Jerome

The 360 swap looks great to me on paper, there just seamed to be
so many 318 loyalist who would rather cut off there $%# before
swapping for some reason. Im leaning towards it the more I read.
I need to move this RV off the inlaws lawn anyway.

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I hear you about the 318 loyalist...it's a great engine. For the life of me, I can't figure out why they can't see it's basically the same engine in the 360 though :confused

Many just see the 360 as a slightly more powerful, but far less efficient version of their beloved 'teen...the reality is, it's not too much less efficient at all.

Definitely if freshening it up, go with the 360. If you are looking to invest a little more, upgrade the pistons to Speed Pro Z8K405P30's (cheap) or KB107's. With either, deck the block about 0.060 too, which will bring your compression up (with NO milling of the heads) to a solid 9.5:1. Also invest in a good 3 angle valve job for the heads. Of course, it all depends on how cheap you could get the machine work/valve job done if going that route..

Doing all that, with cam, headers, and decent 4 barrel (which a working quadrajet is), you can easily be putting out ~ 400ft-lbs of torque, and near 300hp.

Im sold, I'll be sure to snap a before/after pic and post before fall.
I need more projects in my life but the plow pays for it all in winter.

Let me know if you want a hand...I certainly know the engine like the back of my hand. Maybe we'll swap knowledge when I finally get around to digging into the CSX, lol...

I'd go with the KB107 pistons myself though...you can pay ~ 60 bucks more for them, yet you'll end up not needing to deck the block, and still end up with >9.0:1 compression. If the block is an ideal 9.6" deck height (rare, most come out a touch higher), it'll work with 9.3:1 w/ 72cc combustion chambers (high side of the head volume) and 9.7:1 with 68cc head volumes. Plus, you'll have the security of knowing you've got valve reliefs.

swaping in the 360 for the 318 made a world of difference in my PU. Definatly worth it, if I was you I'd try to find a magnum engine and put on a carb intake, but thats just me

Quote:

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Originally Posted by 70challenger452

swaping in the 360 for the 318 made a world of difference in my PU. Definatly worth it, if I was you I'd try to find a magnum engine and put on a carb intake, but thats just me

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Not a bad idea...would also either need to put his 'teen's timing chain cover on (for fuel pump) and I can't recall if the magnum's roller cam comes with a provision for fuel pump eccentric (if not, great excuse to upgrade the cam to a stronger than stock job). Of course, could just put an electric fuel pump on the thing too.

But, you've already got a free/low buck engine waiting.

I believe you could get a complete running magnum for ~ 650-900 bucks though. MUCH better heads too...you could redrill the heads to accept the correct bolt angle for your current intake manifold. Your distributer would work. Also would want the flex plate, as the balance is moderately different on magnum engines.

I just went thru the Summit and jegsonline parts stuff, you can
get slugs,rings,bearings and seals for those v-8s less then I can
have 4 forged slugs for my 4 banger made.

If I was to build something wild and wanted to get creative I dont
think the Magnum on pump gas could match the torque or the HP
I get from the 2.2 and 2.5 hybrids I build :) Love to open the hood
of my plow truck to expose a 460#' torque 4 banger :)

Quote:

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Originally Posted by Prince Valiant

Not a bad idea...would also either need to put his 'teen's timing chain cover on (for fuel pump) and I can't recall if the magnum's roller cam comes with a provision for fuel pump eccentric (if not, great excuse to upgrade the cam to a stronger than stock job). Of course, could just put an electric fuel pump on the thing too.

But, you've already got a free/low buck engine waiting.

I believe you could get a complete running magnum for ~ 650-900 bucks though. MUCH better heads too...you could redrill the heads to accept the correct bolt angle for your current intake manifold. Your distributer would work. Also would want the flex plate, as the balance is moderately different on magnum engines.

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I got my complete 360 out of a 98 durango r/t for $750, and with pretty much just an intake manifold and msd box, other than that mostly stock, it made 322 ft/lbs of torque and 235 horse at the tire, there is no place for a mechanical fuel pump on the truck motors but the crate engines magnums do.

Wow if there wasnt enough to think about, how about my
1985 318 heads on the 1976 360 motor............
http://www.allpar.com/mopar/4bbl.html

Lots of reading, my head hurts!

Your's, being a truck engine, won't have the desirable "302" casting heads...w/ the closed chambers and swirl port intakes. Those didn't hit the trucks until 87 when 318's went with TBI fi. Easy way to check would be to check is to find the casting numbers on an intake runner under the valve cover.

The problem with keeping the 318 heads, is that while you'll have pretty decent low-end, you're giving up good power. First problem is the intake runner size...it doesn't match the intake you've got, because the intake manifold is undoubtedly for a 360 head (since most all 4 barrel intakes NOT specifically for the 273 featured intake runners sized for 340/360 heads, which are larger than the runners for 318's) and will feature a significant step-down from the intake runner of the manifold to that of the head. Factory 4bbl 318's ran 360 heads nearly exclusively to avoid that problem (and ran 360 cams too).

Mismatched runners are fine going from small to bigger....but detrimental going from big to smaller as the case will be (and is currently for that matter) if you continue to use your intake with the 318 heads on the 360.

Some have gone put 302's on hotter engines before...generally upgrading the valves to either 1.88's, 1.92's (chevy valves), or 2.02's. During the process, they also open up the bowl to approximate the new valve seats, blend, and soften the short-side turn. Of course, they also port match the smaller runner's to that of the intake manifold they are running. I'd also highly recommend opening the pushrod pinch. Problem with that is that it's good money to do all that...but you do end up with a good, modern combustion chamber design. But for pretty much the cost to do all this, you can get pretty much more than the above AND lose ~ 50lbs off the front end by getting edlebrock heads.

If you wanted to scan the scrapyards for a good head for the 360, find some 89-92 heads (magnum 360's didn't hit until 93 iirc) for a 360 w/ the casting number "308". They are a kind of "302" 318 head more appropriately sized for a 360...with swirl port design. However, they are still an open chamber style, so no automatic compression increase there. You do get the benefit of increased resistance to detonation/pinging though do to the high swirl nature of these heads. They do flow better than your current 360's heads though.

Probably the best of all worlds as far as scrapyard heads go are the magnum heads. Heart-shaped combustion chambers, that are better than the "302's", Better intake runner design, 1.92 inch valves out of the box, FAR superior exhaust flow (by ~ 20-30cfm), better intake flow (205-215cfm total, ~10-25cfm better than stock), small runners for high velocity and good low-end torque...everything else being equal, these heads alone will net you 20-25 HP and a far wider power-band. They were the "Vortex" heads 4 years before there were "vortex" heads, lol. If you go with magnum's, it doesn't matter if you go 318 heads or 360 heads...their all the same.

Downside to the magnum? It's kind of a hassle to swap...you'll need specific pushrods that allow oil to flow through since the magnum heads have no provision to oil through the head like the LA engines do, AMC flat-tappet lifters that oil through the pushrods, HG, and either drill and tap new intake bolt holes for the correct angle, or get a magnum specific intake manifold (and say bye-bye to the Q-jet, or use a horrid q-jet to holley style adapter, which is not advisable). Also, you're limited in the amount of lift (~.450-.480) you can run without machining down the valve spring seats...not a big deal for a truck engine, however.

The short version though is that unless you are swapping to magnum heads, you're probably better off just having a good 3 or 5 angle valve job done to your current 360 heads by a good shop. For your truck, that'll be PLENTY fine for a 360 built for torque :thumbsup

I am still sitting on my complete 400 powered truck...

I bought it for the 4 speed stuff but aside from the trans I could hook you up with the entire big block setup - great running 400, mounts, manifolds, etc. If you are lucky enough to have a small block 727 in your truck, all you would need to find is a junk big block 727 from just about any car or truck for $50 so you could use the big block bellhousing/case from it... If you have a 904 or anything else you'd need a whole trans.

Just a thought!

He should have a 727 w/ the 3/4 ton even though it's a 318, eh?

If you went that route, I could sell you some Big block heads with a fresh (less than 1000 miles) 3 angle valve job for cheap.

If its a 3/4 ton, I would think theres a good chance its a 727. If it is, to go big block all you need is a case, even from a car then you just use your current transmissions internals and tailshaft to build a good one up in the big block case/bellhousing.

My earlier post never made it (now drunk), both the driver and donor are
727's, I could build a case blindfolded for core case.

What would be the milage from a 9:1 360 vs a 400bbm ?

Not terribly different provided you could get some decent compression pistons for the 400...the 400 has a shorter stroke, which is actually one of the more important factors regarding engine vs engine efficiency, since the pistons won't require as much work to move one complete revolution vs that of a longer stroke engine. Also, the BB has a terrific rod/stroke ratio meaning less thrust loading, and thus less friction forces to overcome as well. The only thing that'll hurt the 400 vs the 360, all else being equal is greater friction of the bearings due to greater bearing area, and likely greater valvetrain resistance.

Hughes engines sells a nice, inexpensive cast piston that'll net you ~ 9.5:1 compression. If you wanted to get trick, just build an engine with a 440 crank, 0.030 overbore to give you a stout 451 ci's...it's a common build with plenty of piston choices, relatively inexpensive choices for engine kits (not chevy cheap though), etc.

Then, instead of 400ft-lbs of torque, you're talking 530ft-lbs.

Thats the only problem with the 400 lol - you will want to build it for power not gas mileage! Otherwise, if you kept your urges under control and built a real mild 400 with a smallish carb and a good tune you could probably get close to the 360 or 318's mileage and still make a good deal more power.

on the other hand, Valiant is right on the money with the 451 build, its a very common which equals inexpensive build that gives you great geometry and a ton of cubes and torque.

I went down and fired up the 360 camper, surpised to see a 2barrel Holley
in such a big vehicle. I gotta go thru the carb before driving it back up
but the motor looks super clean and runs surprisingly well for 7yr old fuel
that smells like turpentine :o

360 is in, first plow session complete and the motor screams
bone stock! The same Q-jet and intake that was on the 318
is now on the 360, sounds like its gonna suck the hood in and
2wd is useless on wet pavement below 50mph.