'68 318 needs umph!

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Hi everyone! im really excited to start my 3rd rebuild, but unfortunately i was raised by a chevy enthusiast and so naturally my first car was a camaro. i bought this diamond in the rough '68 polara. fell in love! i have a 318 w/ a cylinder wall thats scratched to the point where the motor backfires constantly. i want to bore the block but have heard i cant go to .040 over? any recommendations for a bore and combo to match everything? i want an impressive daily driver that'lll turn heads! thanks guys!
 
does it need to go .040" to clean it up ? You may have a hard time finding .040" pistons. Only true way to know how safe it is to over bore is to sonic check it,
 
:welcome:........Not much umph coming from the 318, though they move nicely and are economical, umph doesn't happen.

Since you want it to be a daily driver a 360 swap or crate engine would be an ideal choice.

Thats simply my opinion. Having had most engine sizes available from Chrysler under the hood of a 71 Polara the engines that impressed me the most was a 360 and a 400.
 
Question is, how far do you want to go with this? A little more? An edelbrock performer cam/intake package with a 600 carb, headers and dual exhaust should get you close to 250 ponies with much better torque.
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If you want more, Mopar Muscle did make 400hp with a 318 on pump gas...
http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/index.html
 
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im sure a as low as a .020 bore will take care of the scratched cylinder. im willing to go about 2000 into this motor/trans.. how much HP could the stock three speed handle? its an automatic and just got rebuilt i put a torque converter set at 1200 with the intention of having a stronger motor.. thanks for the input guys! keep it coming! i want to be filled with mopar madness! haha
 
also wanted to know of any local place i can have my block sonic checked? im in los angeles california. thanks again!
 
Another option since you live in SoCal, is go to a pick and pull salvage yard and find a 5.9L magnum truck motor and use that as your build. The compression ratio should be 9:1, swirl port heads with 1.6:1 ratio rockers, molly rings for reduced cylinder wear, etc.. The old Mopar Performance 300hp 360 was just a carburetted 5.9l magnum with a regular distributor. Swap oil pans and it will bolt into your car and up to your tranny. HOT ROD dyno'd one at 319bhp 424ftlbs.
HOT ROD said:
When considering low-buck performance for a Mopar, good power potential and ready availability make the 360 a winner. However, the days of buying a good used but serviceable LA-series 360 to swap are drawing to a close, and even good cores are getting harder to find these days.

The later Magnum-series engines open the door for a number of possibilities. It isn't a problem to find a decent used 5.9 Magnum engine from late-model used-parts sources, ripe for whatever performance plans you might have. In fact, Magnum mills seem to have survived the rigors of service much better than the earlier engines, owing to improvements like a better ring pack with thinner moly rings and effective MPI fuel injection with modern engine management, all leading to a reduction in bore wear. It's not uncommon to pop the lids on a 100,000-plus-mile Magnum and discover negligible bore wear, while the older carbureted small-blocks would have been spent. Good bores and a sound engine are essential to the foundation of a low-buck performance engine.


...the 300hp version is the same engine as in your typical Durango, van, or Ramtruck. With the 300hp crate you get a bone-stock production bottom end, complete with the stock truck pistons and cam. Changes are only the addition of a center-sump passenger-car oil pan, an LA engine-style front cover, a conventional distributor, and a two-plane carbureted intake to replace the factory "beer-barrel" MPI injection system.







Add an Edelbrock RPM Air Gap, 750 carb, Headers and research a cam that will fit your needs. A Mopar Muscle cam from Comp Cams would be similar to a stock 340 cam, but would have more lift because of the higher lift rockers. That would be a very fun motor. Be careful picking a cam if you leave the heads stock because I think the stock magnum heads are limited to about .500 lift at 1.6:1 ratio.
 
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You probably have the 904 transmission, either way 904 or 727 your 318 isn't going to tear one up unless your doing holeshots....
 
so im pretty set on going with the mopar muscle build up for 400hp.. is the trans still gunna last ? or should i just go a step up? what would be a rough estimate of the worth for a 68 polara staight body and just set primered with that built 318? will i make my money or should i save that motor build for another project? i dont really know a polaras going worth.. only what its sentimental value to me is lol.. thanks
 
If your doing this for any value stop now.


I don't think we even know if its a two door, four door, wagon or convertible. To give a value is impossible, however with little or no money invested your ahead of the game otherwise you'll be upside down before you know it.


If your transmission was just rebuilt and your sure its a quality job, you should be fine.
 
Personally, I think the money it's going to take to make that 318 pump out 400 HP is money down the drain and he'll never see so much of a nickel of it back.
Just change the oil and clean it up to make it look nice.
 
wow man :/ such a nice car and to hear it wont bring anything back? i already priced all the parts and machining cost for the motor and its going to be around 1700 just for motor to be complete and around 400 ponies.. i have a 71 baracuda through my uncle that i really liked.. would that be worth the investment? but im definetly not getting rid of my polara.. i love that thing, plus its my first mopar! whether its valuable or not, thing is still bad *** to me! :) well thakns everybody for posting to this thread! i learned more from this one thread than in my whole life about mopars! im sure will all be in contact cause im going to need your guys' help! haha but if any of you guys ever have anything for sell dodge related let me know! i love rebuilding motors for the fun of it and have a savings just for that hobby. thanks everyone!
 
unfortunately like most other aftermarket parts you generally don't get your money out of performance parts. A 1700 paint job will get you further than the same in go fast parts.
 
The problem is there is little value in your Polara and it pains me to say it. An awesome 68' Polara is less valuable than a rusted out 71 Barracuda.

In Chevy terms it would be like comparing a 70 Chevelle to a 68 Impala with a 307.


Most guys on this board would rather have a big Mopar than that Barracuda but we are the exception to the Mopar masses.
 
whats up man, any progress??? if not, dont get discouraged! You may not have one of the more "saught after" Mopars but since youre not planning on selling it anyway, its actually a good thing. C bodies (especially the 60s cars) have awesome body lines and depending on what your tastes are, they make awesome mild kustoms. As far as resale values go, Mopars are a totally different ball game than what goes on in the Chevy/Ford world. The amount of C bodies that bring in the big dough are realatively few and they typically have to be either low mileage, great condition survivors or "Day 1" type restorations with correct paint, plating, date coded parts and NO CUSTOMIZATION! On your car, youll never get anywhere near what you put into it if you do a "factory stock/correct" type resto so if you go that route, its gotta be your preference for it to be worth it. Thats what a lot of C body guys like. HOWEVER, depending on what your tastes are, mildly built cars like ours do pretty good in the "Kustom" scene. They have a lot of character, there arent too many around, and with the right set of mild mods they turn a lot of heads and bring in pretty good dough if you do a reasonable amount of the work yourself. Thats what i like and thats how im setting up my New Yorker... Mild Kustom, and definitely a keeper.
Its pretty obvious that youre already a car guy so all you really need is some Mopar specific info and youll be set! Another thing thats unique in the Mopar world is the amount of help you get from the other C body folks. There arent too many of us out there so if your sincere about your interest, youll typically find that most of us are more than willing to show you what we know. Good luck man!!! AND POST SOME PICS ALREADY!!!

Yorker.
 
My friend, want more ponies under the hood WITHOUT spending tons of bread and hard earned dough on performing sonic checks and what not, on a tired original 318 yawn block motor? Watch c-list, go to the junk yard, word of mouth or search the internet for donor car with a decent running 383 or 440 motor in it. If your not confident enough, bring someone with you to check out the health of the donor motor; hear it running if you can, check for smoke (black, or white), make sure the radiator fluid is clear, yada yada. If it's still got some life in it yank out the 318 (along with the 904, if its not already a 727) and swap the big block combo in. Bingo!! you have 75-100 more horses. Easiest, most cost effective, painless way to gain more umph! That is what I would do, mopars are easiest cars to work on. If you have enough hands and plan it out you can do this over a weekend...and you don't need any high priced services or fancy sonic checking equipment. If you somehow blow up the big block doing hole shots, repeat said steps. Just my 2 pennies. Have fun!
 
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