Technical Lets build a small block Mopar

I got my 37 Dodge pickup on the road this year with a stock 1970 318. Every time I drive it I get a smile on my face, but I know it could be a bigger one. I want to build a 350 to 400 hp small block mopar. I plan on aluminum heads, but don't know what brand works the best. Is it worth building a 318, or start with a different small block? I know the pistons are down in the hole on a 318 but I know that it cam be changed. I want to keep this motor with a carburetor, and points. I also don't want to build a stroker motor, but reliability is important. Lets here what combos work for you Mopar guys. I know 73rr is up on Mopars, so I hope he chimes in, and anyone else that has worked with them.
Thanks Tony

 

my first car was a 68 roadrunner it was 2 yrs old 383 4 spd. I've owned and driven about every mopar muscle car big and small block if you have ever drive a good running A body 340 car you would realize that 318 belongs in your grandma's monaco

 

See if you can find a 360. I don't know what's around these days.

but keep in mind they changed the 318 and 360 to the "magnum" engine design somewhere along the way, and intakes are different, etc.

If you don't want to build a stroker, then starting with the biggest engine is the next best thing.

 

Word. Those things were surprisingly stout in their day.

 

A ride in a 340 4 speed Duster changed my world in about 1979. Wow. Have a friend with a Dart and a 360 crate motor. Wow Wow.

 

If you had done any research you would have known Chrysler never put a 4 barrel intake manifold on a 318. so why would you put aluminum heads designed for better flow on a motor that was intended for longevity and dependability. those Chrysler engineers in the 60's and early 70's were the best of the big three.

 

You can get 400 horse out of the "teener". Magnum motors have roller cams as do post 88 360 non magnum engines and even earlier 318's.
The easiest way to get 400 horse is to buy a junk yard 360 magnum, bolt on some EQ iron heads, a dual pattern cam 750 cfm carb and headers.
340's are over rated.
The beauty of the LA Chrysler motor is the large diameter lifter bore and is easily stroked.
340 has the largest bore. The old school trick was to grind the 360 larger main crank down to the 273, 318, 340 crank main journal size.

 

I would use a 5.9 magnum u cam get a carb intake for the magnum heads or have the heads drilled for old style intake.I own 2 340 engines & would still use magnum engine.The heads flow better than the 340 heads.Look up Abody website,lots of info,Jimmie

 

Stout wasn't the "Word" I used the first time I rode in my high school buddys' older brothers 1970 AAR Cuda, 340/3x2, that thing was an animal.

 

I have a 360 magnum out of my 97 ram just sitting there. I have thought about it i just didnt want to build another set of headers. Thats the only thing stopping me.

 

Your Magnum 360 will bolt up where your 318 is for the most part. You can buy a different intake manifold to use a carburetor, and your distributor will drop right in.
The headers should bolt in but the flanges may not match the port shape. The 360 is external ballance so either the torque converter will need to be changed to one with a counter weight, or a weighted flex plate from B&M can be used. The magnum valve covers are slightly different, but i heard LA valve covers can be modified to work.

 

And if you don't want to do the 360 Magnum (for the record, a 318 Magnum cam is hotter then a 360 Magnum cam), but want to keep the 318, a factory 340 grind cam, double roller timing chain, headers with dual exhaust, and a set of intake port matched 318 heads to a 4bbl intake will work very well on a street motor up to 4,000-5,000 rpm (a street motor seldom sees more rpm) and will be very reliable. The same stuff in an LA 360 (the 340 cam is hotter then a 360 cam) will provide more power, its hard to beat CI on the street.

Most built street motors are over cammed and over carbed. Street motors don't need the latest quarter mile speed tricks, unless your racing. The more radical you go, the less reliable, and the worst the street manors of the package becomes. Gene

 

This is all great information. One of my future builds will be a 47 Chrysler with a LA engine.

 

I drove a 80 D100 with a 4 speed overdrive for years. It had an Edelbrock intake ,600 Holley, headers and a mild cam. It pulled a trailer really easy and was fairly quick. A set of Magnum heads would have made it better. Maybe some Edelbrock heads.

 

As I look into the Magnum motor, I find out that there is not a way to run a mechanical fuel pump. Can a set of Magnum heads be bolted to a LA motor? I also agree that there is no replacement for displacement. I have a set of J heads that I could get reworked, I figured that I would loose some weight and gain some power with aluminum heads. Buy the time I rebuild the iron set it would cost about the same. When done more reliability is important than having big horsepower. I also have 2 different new cams, but no info on them. I also have 3 different intakes, one edlebrock torker, 1 performer, and 1 6pak. I am running a 5 spd. My original plan was a better set of rods and pistons, clean up bore and crank, then double roller timing chain, and cam. A good set of heads, and intake with a 700 cfm carb.
Tony

 

Magnum heads will work with amc lifters.Magnum rockers oil through the lifters.Go to magnum mopar site for info.They have info onusing la parts on magnum engine.jimmie

 

Factory Magnum heads are prone to cracking. Ive heard good things about the EQ Magnum heads and you can buy them drilled for the non-magnum intake manifolds. I also read that the eddy heads should be dismantled and checked as their Quality has suffered. The valve guide clearances can be bad and full of shavings. I think those J heads will work good on the 318 with some work on the exhaust ports.

 

Tony, The 318 can be a mighty big performer if you have enough in your check book. EngineBuilderMagazine did a 318 stroker back in 2014 for a charity raffle. They spelled out every detail and it was a monster. Here is a link:
http://www.enginebuildermag.com/2014/09/breaking-rules-392-magnum-engine-build/
If you need to keep costs in line then a more subtle approach can be used with a Scat or Eagle crank and the old J heads. As mentioned, the early 360 is still a very capable engine and not to be overlooked. Bump the c/r and use a decent cam and your all set for most street use.

For most street applications, torque is the King and that usually means the longest stroke and the most compression for whatever engine in question.

If you find yourself unable to sleep some night then troll through the web listings and see what has worked for others. You might also buy a few of the various Mopar related ..."build an LA engine"... books for reference.
As Gene said, radical builds are not street friendly.

.

 

Also, if you start with a firm, realistic number for your budget, and also let us know what all parts you have laying around, we could help you figure out the most reasonable approaches.

 

73rr and Jim, thanks for the input. I haven't thought much about a budget, but I would like to stay around $3500 if possible. I knew there was something about building a 318, but I don't have a bottomless check book. I did find this motor for sale in my area, down side is I don't know the quality of parts he uses. Its right in the range of power I am looking for. He builds motors for a living, offers a year warranty. It looks to be along the lines of a Mopar performance build for less money.

1973 360 Chrysler bored .040 with hypereutectic pistons and moly rings. Reground crank and resized rods. Melling cam with .444 lift IN. / .467 EX. duration at .050 is .214 IN / .224 EX. J Heads with 2.02 IN and 1.6 EX valves. Comp cams valve springs. New valve guides and hardened seats for unleaded fuel. Melling double roller timing set and oil pump. Performer rpm intake, quick fuel 600 carb. Summit racing mopar style ignition. Edelbrock valve covers. This motor is completely streetable and has been dynoed. On premium pump gas it makes 355 hp at 5100 and 390 trq at 4200. Dyno sheet included. $4000

 

Let me play the devils advocate........
Was it run in on premium because of too much c/r or issues with ignition?
Are you willing to pay for premium every time you fill up? Around here, premium can be anywhere from 30¢ to 50¢ a gallon add-on and that will add-up.
The rest of the parts list is pretty generic, easily duplicated.

If you know the builder and have faith in his ability to do the job then the 1-yr warranty is good. If he is an unknown factor then what hoops would you have to jump through to get anything from the warranty? And, what does the warranty cover? Who is responsible for what? What are the exceptions/limitations? When does coverage start?

Gary

 

I saved the hard copy of this magazine for a build down the road. Just some food for thought.
http://www.hotrod.com/articles/318-small-block-build/

 

I'm using a 5.2 (318) std bore from a '95 Jeep grand cherokee that I got from the pull it for 100.
Tore it down, had it vatted, 'dingle ball' honed it (DO IT upside down, so the grit doesn't fling all over the inside crank area!! i use diesel fuel as a lube for the stones)
Had block decked .065 to raise compression for stock dished pistons, and if I can remember, think I'm at .010 in the hole.
Just used cast rings so it seats in quick and with the later high nickle, Magnum block, get the advantage of a Roller cam.
Had Bullet cams here do a regrind on it (only 100.00 or so VS 3xx.00! AND they're right down the road..)
258/266, (208/214 @ .050) 480/488 lift (504000 S82515 if anyone wants to know grind info. Talk to Kurt)
Using Ford pushrods to get me within .010 or so. Spent the money on the heads. Engine Quest with the larger valves, heart shaped chambers and TONS better breathing.. (they can be ordered with BOTH intake patterns. I'm kicking myself for NOT getting both..)
Just a cheap Ebay air-gap style CARB intake (130.00?? VS 300 for a hughes) Have to use the early 70's thermostat housing that I had to go exploring for. And a Ebay HEI style distributor/wire combo (125.00?) NGK UR4 or 5 plugs and some Ebay block hugger headers (120.00?) If you get one of these HEI or newer distributor, get the style gear to mate with the cam. CAN'T use a regular dizy gear on a roller cam!!! Just get one at the pull it..

It's being bolted to a NV3500 from a '97 Ram1500 but it's all going in a 3000lb Jeep cherokee that was a 4cyl, 5spd 2dr, 2wd that kept giving me electrical CPS failures.. With a 3.54 8.25 rear, 28" tall tires, it should be a sleeper to say the least.
It's been a project and hope to have it running with any bugs worked out by spring.
Then going to a FI-Tech injection. one of the BEST/cheapest injection setups out there today!! (just don't have the 900.00 right now.)

It's my first Dodge/Chrysler build, but hoping at least 325hp
Hot Rod or Car Craft did a build on a 5.2/318 that got VERY respectful results. 400hp!!.
That's where I got the idea from.
..Also, just to be different and stealthy..
If you can deal with all the pop-ups.. http://www.hotrod.com/articles/mopp-0409-318-engine-build/

The heads were the most expensive at around 850./pr. Most everything else was between 120-150. But, most parts are new except the short block. (OH, and got the pan/pickup for the Jeep for a rear sump. CAN'T use the early pans' on later magnum blocks. New pan Ebay for like 50.00.
AND, since its' going to be a "new build" with new radiator. I'm going with Evans coolant since it gets soo hot here (memphis area) in addition to a remote oil cooler routed to a cleaned, Grand cherokee oil cooler 'modded' in front bumper (apprx 5"x16")

Hope it works out for you. PM me if you need any more info.
..also, IF i can remember all of it.. It's been a couple years because of budget. BUT, getting close!

Errol

 

Oh, the EQ heads are alot thicker deck and chamber area to resist cracking UNLIKE the stockers.
WELL worth it when you add all the machine work to 'fix' stockers too.
E

 

I would call McCandless Racing and see if they have any deals on a 360. I bought my heads from them, bored my 360 .030, ground the crank, Comp Cams 280 XE (or maybe it was 265 XE ) 750 Edelbrock, headers and I had all the HP I could use on the streets with my avatar, probably 350+. I used recommendations from Comp and it was a great motor when I sold it.

 

I never heard of "offset grinding the main journals" wouldn't the crank run eccentric possibly causing the crank throws and maybe rods to hit the block.

Making 400 HP with the engine you have now equals $$$$$

Pat

 

You are correct. That was possibly the dumbest thing I've ever posted. Possibly.

 

Gary, thanks for the link and thoughts. I always run high octane in my truck so that's not a problem, however his reputation for quality is a problem.
Errol, thanks for the input on the 318 magnum and link. I see a lot of people saying that the 318 will cost a lot of money, but the few links on here show it won't.
I see that everyone wants to take .050 off the heads to increase compression ratio, but wont that change how/where the intake sits, as in lower? Also a lot of use in the iron head, casting #302, but can a set of aluminum ones be a better choice? The only reason I don't want a strocker motor, is I have heard that they don't have the reliability that a stock one has.
I would build my magnum motor if I could use a mechanical fuel pump. I have been learning a lot by looking into this. When I do stuff like this for the first time, I usually don't even know where to begin, and that is where the H.A.M.B. comes in. I get pointed in the right direction.
Tony

 

I may be wrong, it's been a LONG time since I fooled with 318's and I was pretty young and dumb when I did, but IIRC most of the 360 stuff as far as intakes and accessories bolts on to the 318.

I had an Orange 72 Satellite Sebring when I was 20 and one of my biggest regrets was not IMMEDIATELY putting a 4bbl on there because I could tell that the engine was starving with the little 2bbl when I stood on it.

I had the wild notion of putting a six pack setup on there (doable, but beyond my budget and needs a built engine)

http://www.edelbrock.com/automotive/mc/manifolds/chrysler/performer-sb.shtml

http://www.edelbrock.com/automotive/mc/cylinder-heads/chrysler/victor-sb.shtml

 

"I see that everyone wants to take .050 off the heads to increase compression ratio, but wont that change how/where the intake sits, as in lower?"

A computed amount is also taken off of the intake side of the head so the manifold still fits.
Pete