Best 273 and 318 builds (NO 360's please)

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jeremiah2146fa

jeremiah2146fa

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After batteling it out in several forums, I realized that it's pretty hard for the little small block guys to get any big power tips for they're mills without being lectured about the advantages of bigger starting points so I decided I'd start this thread for all of them. Let's get this out of the way, There are plenty of reasons why starting with a 360 can make for a cheaper, easier, or more streetable build, but this thread isn't for all of that. This thread is to benifit all the guys who want for WHATEVER the reason to start with a 273 or 318 and make big numbers on the dyno streetable or not. I know that there are lots of ways to do this, 390 strokers, magnum and swirl port heads, superchargers and turbo's, even the probably bad idea 360 crank middle weight stroker.
The only rule for this thread is no "ditch it for a bigger motor" posts!
Sooooo... Let's see what you got guys!!! :cheers:
 
So this is a strickly a stock cid build thread for the 273/318 sized engines. Overbores OK of course. DUH!

I did a 318 up years back. Simple and cheap while running high 13'2 in some set ups I've had.

.030 - 318 high comp pistons, 2.02/1.60 J heads, Torker II, 600 DP Holley, headers and a crane cam. 216/228 - .454/.480 - 112

While still low on compression due to big chambered heads, the 4spd and 4.10's helped propel the car into the low 14's/high 13's @ about 100/103 mph or so. (It's been awhile since I ran this one.)
 
Nice, I like it! I wonder what would happen with a little more compression or forced induction?
And yeah, stroking and over bore is fine, just no bashing on guys for starting with the 273 or 318 block. There's a LOT of really cool builds out there for these little guys and we don't get to hear much about them. I'm putin a 360 in my duster this weekend because of the cost factor, but I'm interested in this too as I'd like to build a 273-318 just for the cool factor at some point. I did a 323 swirl port motor and got a kick out of telling people that it started out as a lowley 318!
 
OK, 318 stroker builds are OK then? Seems to kick the words that said, Why is someone allways stating, get a 340/360 out the window then.
 
Here is my junk motor build that I threw together until my 360 is finished. Very happy with it and people are suprised that it's a 318.

318 .040 over
Flat top pistons with valve reliefs
.060 deck height
.028 head gasket
Comp XE-256 flat tappet cam
Stock magnum rebuilt heads
Chevy beehive springs
1.6 Chevy roller rockers with Comp guide plates
CAT gear drive (I like the sound)
Holley 600 4160 carb with secondary metering plate (Jetting 67/72, 7.5 PV)
Hooker comp headers

3K stall convertor
3.91 gears
28" tire

Fun little motor. This will be going in my 75 W100 once my 360 is done.
 
BaDart no cussing in this thread. You said the "360" word twice in your previous post:-D You might be getting a nasty gram from the mods soon.
Really though I am happy to see this thread. Not everyone wants to or has the option to just build a______(fill in the blank). Some have to get the most out of what they have. I like to see people that do good with very little. It promotes innovation and ideas for everyone. I wish I knew more about squeezing performance out of a 273 or 318 or any engine for that. My 318 builds have never met my expectations but, I really haven't put in the effort to learn and understand what it really takes. I'm kinda like the guy that wants the super duper killer engine by just using more cubic inches and relying on hear say for my builds. Don't get me wrong I have learned more from this site than anywhere else:cheers: I'm in the process of building another and this thread has opened my eyes to start digging deeper to understand what it really takes to build a really reliable performance engine. Good luck finding the info you need and I look forward to reading this thread.
 
I wanted to keep my HP-273 in my 66 GT so I bored it .030, used Egge's 10.5:1
pistons (which are @ 9.67 with some head shaving and a .025 thick Mopar gasket) The Egge's are 68 grams lighter than the stockers so the assembly got balanced.
I used a Isky E-4 solid lifter cam ( 260/.425/108 deg) which is a bit bigger than stock specs driven by a Cloyes street double roller.I also installed a MP windage tray. I had R&J performance build my heads. They milled them .030 to save compression lost by the thicker head gaskets. They replaced all the valves and added 340 springs. They also installed bronze guides and did a port match and mild port job along with a polish to the chambers. I will use the stock Prestolite dual point distributor and the stock cast intake ind the original AFB carb. I am presently working out the bugs with pushrod length as I assemble and paint the pulleys and brackets. I was hoping to get it assembled and drivable by Memorial day but I don't think I'll make it. I don't want to rush it. This has been a fun build for me. I have overhauled engines before but I have never done one to this extent before. Thanks for this thread. toolmanmike

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That's awsome! I'm dying to see how it turns out. Are you gonna be able to dyno it when your done? It'll be interesting to see how a decently flowing good compression 273 runs.
I posted this on another thread, but one of my favorite childhood memories was of my big brother taking me to a mopar only race and seeing a 1967 belvedere with 14" numbers on the fenders reading "273CI" eating big blocks in the quarter. I never got to talk to the driver or find out any specs, it looked like a trailer queen. I think I remember it running 10's! I'm sure it was a wild race only build and probabley running a LOT of nitrous, but DAMM it was cool!!!
 
jeremiah2146fa said:
That's awsome! I'm dying to see how it turns out. Are you gonna be able to dyno it when your done? It'll be interesting to see how a decently flowing good compression 273 runs.
I posted this on another thread, but one of my favorite childhood memories was of my big brother taking me to a mopar only race and seeing a 1967 belvedere with 14" numbers on the fenders reading "273CI" eating big blocks in the quarter. I never got to talk to the driver or find out any specs, it looked like a trailer queen. I think I remember it running 10's! I'm sure it was a wild race only build and probabley running a LOT of nitrous, but DAMM it was cool!!!
Click to expand...

A run on the dyno would be fun. I don't know if I'll have any money left. LOL
 
jeremiah2146fa said:
I just found this site. I thought nobody did the 349 strokers because you had to machine the block or something. I thought there was a reason why it was a bad idea? Maybe it's just a bad idea if you use a stock 360 crank?

http://www.rpmmachine.com/318-349-chrysler-stroker.shtml
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Theres nothing wrong with the crank cut down to size. It'll just be better if the crank gets re-heat treated. No extra clearancing needed or machine work to the block to fit it in.

Poppabear said:
This is cool, been thinking about doing a 318
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The 318 can preety well. You have to remember a few things about the 318 to begin with so you don't make a few big and costly mistakes that end up having you move slow.

My build above is a classic low compresion mistake/part mismatch.. But itwas able to still move OK. Mostly due to the abilty to move air at a high rpm. The intake helped there and the gear ratio to move through the gears quickly.
 
my 318 combo will be Iron Ram 202 heads, Hughes Engines whiplash cam, flat top pistons for 9.25 compression so I can still run on 91octane. Stock 2500 converter and 3.23 sure grip in my 68 Barracuda. 3126lb car should run low 13s and be plenty street able.
 
Here is some info from my library of magazines, all pertain to 318s. Engine Masters Winter 2008 Vol 11 No 4, Popular Hot Rodding January 2009, Engine Masters Winter 2006 Volume 9 No 4, Engine Masters Spring 2010 Volume 13 No 1, Car Craft March 2010. Hope this helps, ps nothing is funnier than when I saw a 318 dakota smoke a 360 RT off the line and held a 2 car length lead the entire quarter mile, cubic inches indeed!
 
We always say that the x brands get more aftermarket share because of supply and demand. So with that in mind it seems to me that the biggest market share for mopars would be the 318 powered abodies. Why then has no one ever tried to take advantage of this market? If someone would sell a combo that would utilize the stock pistons of a 318 yet be capable of propeling an abody into the high to mid twelves with proper gearing and suspension it seems that this would be the best market for mopar guys money. The kit would have to sell for under $3000.00. If a 302 ford can be made to
to perform as it does, why not a 318??
 
Because the 340 took the thunder away from the 318 as the only performance engine for small blocks. MoPar/Chrysler never got behind the 318 as a engine that could perform. It was a basic people mover engine. Even though it has many advantages.

Getting a 318 into the mid 12's isn't to hard, just so much easier and street freindly with a larger engine. Until recently, no one really made a performance piston for a 318. KB makes a few that are resonable in cost, but still more expensive than the larger engines.

On the cheap, after a bottom end rebuild with high compresion pistons, it's just a big cam, gear, converter away with 360 heads and a capable intake and 750 carb with headers.

Engine parts for this could be done under/at $3000 after the shortblock is rebuilt.
Gear, converter, tires, suspension and chassis work extra.
 
rumblefish360 said:
Because the 340 took the thunder away from the 318 as the only performance engine for small blocks. MoPar/Chrysler never got behind the 318 as a engine that could perform. It was a basic people mover engine. Even though it has many advantages.

Getting a 318 into the mid 12's isn't to hard, just so much easier and street freindly with a larger engine. Until recently, no one really made a performance piston for a 318. KB makes a few that are resonable in cost, but still more expensive than the larger engines.

On the cheap, after a bottom end rebuild with high compresion pistons, it's just a big cam, gear, converter away with 360 heads and a capable intake and 750 carb with headers.

Engine parts for this could be done under/at $3000 after the shortblock is rebuilt.
Gear, converter, tires, suspension and chassis work extra.
Click to expand...

I agree with all the above except what I am saying about market share. 318s are the untapped market. I have owned Mopars since the mid 80s and 318 get more press now then ever. I am looking at this as someone who is a business owner.
 
stroked 340 said:
13's are quick:dontknow:..sorry couldn't resist..
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Techincally, they are. I guess if a person is consistantly running 10s and 11s, the perception of "fast" may be altered a bit. The majority of new cars these days are stuck running 16s, so it is fair to say that 13s and 14s are quick. The fact of the matter is that times run and whether or not it is deemed "fast" is really a relative statement to what is being run, which is this case is a 273 or 318. 12 to 14 second times for these motors are quick for them and still quick in the overall grand scheme of things.

Not everybody can build 10-11 second machine, nor drive it daily on the street.

My 318 is a .030 over build with TRW 8:5:1 pistons, Mopar distributor, Hooker headers, slightly reworked stock heads, COmp XE268 cam, Edelbrock 600 carb, Performer intake, 4" air cleaner, in front of a 904 with TF-2 kit and 3.21 geared 8.25 rear. With a 2300 stall in my Duster, it runs bottom 14s on 27" tires. For the gear and low compression running on 89, that is plenty quick and will have no issue running 100k miles.
 
My recipe is the same basic idea as any other engine size. Get pistons that yield a decent true compression ratio. Have the lower end blueprinted to make sure you have things right. Give it a set of heads to move enough air for the power level you want. Stick a cam in that will encourage you to drive it rather than hurting the enjoyment. The difference comes in parts costs. you can get 318 pistons cheap that will do a decent job. You cant get 273 pistons IMO without going custom forged.
 
moper said:
My recipe is the same basic idea as any other engine size. Get pistons that yield a decent true compression ratio. Have the lower end blueprinted to make sure you have things right. Give it a set of heads to move enough air for the power level you want. Stick a cam in that will encourage you to drive it rather than hurting the enjoyment. The difference comes in parts costs. you can get 318 pistons cheap that will do a decent job. You cant get 273 pistons IMO without going custom forged.
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I used Egge 10.5:1 pistons in my 273. I was a bit disappointed that the true compression ratio was 9.6 with some milling of the heads but it will be very streetable and pump gas friendly. Who knows what the factory compression really is? I didn't think to check before I took the engine apart. I agree with you. I feel the heads are the most important for building power. You 318 guys can use what ever is available and what your pocketbook can afford. The 273 guys should be happy with reworking the original heads or maybe stepping up to a set of mid 80's #302 castings. Anything bigger on a 273 will be a loss on the street. I am building a +.030 273 with 9.6/1 compression, balanced, with ported heads and a Isky E-4 cam. I am getting closer to hearing mine run. Many of you have read my thread and saw my progress. I won't post any photos here but you can see the progress here.
http://www.forabodiesonly.com/mopar/showthread.php?t=94343
toolman
 
Tnplumber said:
I agree with all the above except what I am saying about market share. 318s are the untapped market. I have owned Mopars since the mid 80s and 318 get more press now then ever. I am looking at this as someone who is a business owner.
Click to expand...

I see. One thing for sure, your dead right about the teen getting more press than ever. I think it's good. The market is very untapped.

stroked 340 said:
13's are quick:dontknow:..sorry couldn't resist..
Click to expand...
LOL, maybe you should try, LOL! MOPARJ below makes a very accurate statment.

MOPARJ said:
Techincally, they are. I guess if a person is consistantly running 10s and 11s, the perception of "fast" may be altered a bit. The majority of new cars these days are stuck running 16s, so it is fair to say that 13s and 14s are quick. The fact of the matter is that times run and whether or not it is deemed "fast" is really a relative statement to what is being run, which is this case is a 273 or 318. 12 to 14 second times for these motors are quick for them and still quick in the overall grand scheme of things.

Not everybody can build 10-11 second machine, nor drive it daily on the street.
Click to expand...

I was very happy with the teens performance in my Duster before I sold it. It ran preety good for what it was and had bolted on. Which was basicly it. Just bolt on's and a small cam.

It was a different build than the normal stroked edel. headed combo so often seen and borde with people screaming. It's also a pleasure when you beat another person with what they think is a hot car/engine and you tell'em, "OH, it's nothing special, just the ave. people mover MoPar engine... that lowly 318 with a 4bbl and headers...that's it."
And there jaw drops....LOL!
 
It was a different build than the normal stroked edel. headed combo so often seen and borde with people screaming. It's also a pleasure when you beat another person with what they think is a hot car/engine and you tell'em, "OH, it's nothing special, just the ave. people mover MoPar engine... that lowly 318 with a 4bbl and headers...that's it."
And there jaw drops....LOL!
Click to expand...

LOL...maybe someday..lol...........
 
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