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

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The 268S cam is a great choice, but small port heads perform better with single plane intakes. Think stock 273 4bbl, marine manifolds, Holley street dominators, Edelbrock streetmasters, or a real find, the torker 318.
I agree, but the truth is the stockers dont have enough plenum for a good turn and eveything else is too large or unobtainable. Not to mention the lack of gearing in this car and therefore limited rpm. Hence my choice.
 
here is my 318:
KB-845 forged pistons @ .030 ($350/set on ebay)
stock 340 forged crank 010 010 ($120 on ebay)
stock valve sizes 302 heads ported by myself
11.3:1 compression
273 rockers
comp xe-274s solid cam
air gap intake
750 mech sec carb off my 360
3000 conv
4.30 gears
nuthin fancy, but it runs 13.40's here at 5800'
Build that 318, there is nothing wrong with them! I get alot more respect running 13's up here with a 318 than I did running 12's with a 360!
 
here is my 318:
KB-845 forged pistons @ .030 ($350/set on ebay)
stock 340 forged crank 010 010 ($120 on ebay)
stock valve sizes 302 heads ported by myself
11.3:1 compression
273 rockers
comp xe-274s solid cam
air gap intake
750 mech sec carb off my 360
3000 conv
4.30 gears
nuthin fancy, but it runs 13.40's here at 5800'
Build that 318, there is nothing wrong with them! I get alot more respect running 13's up here with a 318 than I did running 12's with a 360!

That is a good little motor. I like that combination. At sea level, it would easily be in the 12s.
 
I like the 318, but I wouldn't limit my build on the regular 318 heads...I'd use the RHS units, ported, with a retro fit hydraulic roller cam, 1.6 rocker arms. 10.5:1 Cr, gear drive, yada yada...
 
My 318 in my '46 rat rod Dodge pickup runs quite well. I have not had it to the track for time slips though yet.

*Stock 318 bottom end -'84 Diplomat police car
*Late 80's Weiand single plane intake w/1inch Moroso spacer
*Modified 600 Holley
*Mopar performance 450/455- 268*/276*cam
*Headers
*Shaved 360 heads w/3 angle valve-job

904 and 8.25 rear with a 3.55 gears

It is pretty strong and has a nice "potato potato" idle. 2800 pounds :cheers:
 
The 66 is now a ballanced and blueprinted Commando with a E-4 Isky cam. The next 273 for the 66 Formula S is likely to be a ballanced and blueprinted +030 273 with TRW forged 2 barrel pistons, .

Are these some old stock TRW pistons? I could not find these anywhere, went with some Federal Mogul cast pistons.
 
Thanks for the suggestions, Head bolt torque was gleaned from some well respected racer in my forgotten past. Been working trouble free for 30 years. These are not small port heads. All the above intakes are a power loss to a stock 340 intake. Power on this engine in a 4 speed 64 Barracuda is breathtaking. It took an old 11" scalloped Borg and Beck clutch to hold it. I'm not changing anything on this motor. It morphed to this incarnation over 10 years from a stock 2 barrel and everything in between. I'm just letting people know what has worked for me. There is not "one and only" perfect combination.

The 66 is now a ballanced and blueprinted Commando with a E-4 Isky cam. The next 273 for the 66 Formula S is likely to be a ballanced and blueprinted +030 273 with TRW forged 2 barrel pistons, 340 rods and 273 forged crank. I'm thinking a small Racer Brown Mechanical cam and Schubeck lifters. I have a set of 302 heads, milled block and intake sides, Port matched, blended bowls, and cc' chambers. Topped off with a Holley Street dominator single plane and 72 Thermoquad Carb. That should be interesting...


Just the head bolt torque question was directed at you, the rest was my opinion on manifold/cam/etc. :) No harm done.

I am fighting a low buck boat 360 with 318 heads at the moment.... GRRRR :spiderma:
 
I know this has been an idle subject for a minute but here is my 318 as it was and how it will be in the near future:

Was: 318 stock bottom end, balanced with .040 over flat top pistons w/ valve reliefs 1.72 compression height (pistons down .094 in the hole)
Comp Cams 280H cam 230 dur @ .050 480 lift w/1.5 rockers and .512 w/ 1.6 rockers
Magnum heads gasket matched, bowl blended and valve job.
Chinese Air Gap version intake manifold w/ 650 DP Holley carb

Will Be:318 stock bottom end, balanced with .040 over KB 167 pistons w/1.81 compression height (pistons zero decked)
Comp Cams 280H cam 230 dur @ .050 480 lift w/1.5 rockers and .512 w/ 1.6 rockers
Magnum heads gasket matched, bowl blended and valve job.
Chinese Air Gap version intake manifold w/ 650 DP Holley carb

Drivetrain is A904 built be me 10 years ago with shift Kit and 2800 stall Also has a 8.75 SG rear with 4.11 gears.

Ran a best time of 13.91 with the previous motor that had 8.8:1 compression will now be running around 9.7:1

I will be running it in Hockenheim this year in August on a prepared track and I am very anxious to see how it will run.
 
Heres the specs of the motor I'm going to build;
318+.030
Stock crank and rods
xe274h cam
"675" 318 heads, with 1.88's and 1.6's fitted
Edelbrock LD4B manifold
600vs Holley
I'm tempted to zero deck the block, which should bring the CR up to 10.5:1.
Not sure on stall speed for the converter yet.
 
seems like a couple of guys were being kind of childish about things.
It's the go bigger thing getting in the way.

Will Be:318 stock bottom end, balanced with .040 over KB 167 pistons w/1.81 compression height (pistons zero decked)
Comp Cams 280H cam 230 dur @ .050 480 lift w/1.5 rockers and .512 w/ 1.6 rockers
Magnum heads gasket matched, bowl blended and valve job.
Chinese Air Gap version intake manifold w/ 650 DP Holley carb

Drivetrain is A904 built be me 10 years ago with shift Kit and 2800 stall Also has a 8.75 SG rear with 4.11 gears.

I will be running it in Hockenheim this year in August on a prepared track and I am very anxious to see how it will run.

That extra compresion will help bring that cam into play and awake the engine up well. Post up how you did when you get it done.

Heres the specs of the motor I'm going to build;
318+.030
Stock crank and rods
xe274h cam
"675" 318 heads, with 1.88's and 1.6's fitted
Edelbrock LD4B manifold
600vs Holley
I'm tempted to zero deck the block, which should bring the CR up to 10:1.
Not sure on stall speed for the converter yet.

Vb, this build of yours is coming along very nice. IMO, I'd go for as much compresion as pump gas will allow. The cam is big enuff to use a good ratio.
 
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.
Not having the "A" pool of knwledege, to draw upon,(this forum), I purchased a pre magnum, roller cam 318, complete engine. This to power my 67' cuda coupe. Plans have change since then and this build is to propell a 2,400 lb., Jensen Healy roadster. I have magnum "eddy's" and performer rpm, dual plane, of which I believe will tend to limit power over 6k rpm. ? Steel crank and .02" "hyper" pistons, shot peened magnum rods with ARP. bolts. I'm thinkin this should hold more rpm. ? Edelbrock says this is "only" manifold for Magnum heads. Thoughts ? Thanks, ateam.:cheers:
 
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??

Its because the late model Ford 302 shortblock is very useable as-is. The machining is very consistent and the pistons are not a mile below the deck like a 318.

All stock (late model) 302 heads are like Mopar "302" 318 castings. LOL. They've got wedge shape combustion chambers.

Also there are a zillion awesome aluminum cylinder heads for small block Fords. Hell, even the Ford GT-40P heads they put on the explorers are awesome. 200 CFM stock, 58cc combustion chamber, and they don't crack.

And they run hydraulic roller cams, and there are a million performance grinds for them.

Unfortunately, it seems like you have to go to the machine shop to make a 318 run half decent, and if you're spending machine shop money, the $250 for a core block 360 is an insignificant spend that will net great returns.

HOWEVER, I'd be curious what you can actually get a stock shortblock 318 to run at the track. As I think this would actually generate some interest. There is so much variance in stock shortblocks (and many of them are soooo old) that it would always be a case of "your mileage may vary."

Of course, it takes some pretty good RPMs to get power out of a little motor, and I don't know how long some old 318 shortblock is going to tolerate being spun to 6500 or so.

You'd need a good set of cylinder heads (as in Magnum/Iron Ram heads or LA-X RHS heads with small wedge shape combustion chambers and good ports for a real intake manifold. A custom cam that was ground to crutch the lack of compression, and all the bolt-ons.

With a 58cc head, and the pistons .100 in the hole (my stock 71 they were .110 on one side, .095 on the other), you could get the compression up to 9:1 with the skinny head gaskets, maybe a smidge more if you didn't have valve reliefs.

Again, if you're starting with a hydraulic roller block, your ultimate potential would be higher because you can get so much of a better camshaft.

I've got a decent mid 70s 318 laying here. I've been tempted to try something like this, but so far its more fun trying to get my 5.9 into the 11s rather than a 318 into the 12s.

Steve
 
Not having the "A" pool of knwledege, to draw upon,(this forum), I purchased a pre magnum, roller cam 318, complete engine. This to power my 67' cuda coupe. Plans have change since then and this build is to propell a 2,400 lb., Jensen Healy roadster. I have magnum "eddy's" and performer rpm, dual plane, of which I believe will tend to limit power over 6k rpm. ? Steel crank and .02" "hyper" pistons, shot peened magnum rods with ARP. bolts. I'm thinkin this should hold more rpm. ? Edelbrock says this is "only" manifold for Magnum heads. Thoughts ? Thanks, ateam.:cheers:

Hughes Engines (and maybe others?) will drill your magnum heads so you can run LA intake manifolds (I recommend the LA Performer RPM or RPM Air Gap). Way worth it. There are hassles with trying to run the Magnum RPM when you run the LA front cover (water pump hose alignment, weird magnum water neck, etc.)
 
Not having the "A" pool of knwledege, to draw upon,(this forum), I purchased a pre magnum, roller cam 318, complete engine. This to power my 67' cuda coupe. Plans have change since then and this build is to propell a 2,400 lb., Jensen Healy roadster. I have magnum "eddy's" and performer rpm, dual plane, of which I believe will tend to limit power over 6k rpm. ? Steel crank and .02" "hyper" pistons, shot peened magnum rods with ARP. bolts. I'm thinkin this should hold more rpm. ? Edelbrock says this is "only" manifold for Magnum heads. Thoughts ? Thanks, ateam.:cheers:

What LXguy said and;

I do not beileve the Magnum heads or intake will limit RPM in anyway except the prfile of the cam and the springs abilty to control the valve at high RPM's.

Shotpeened rods are a plus but do not hld a key to more power or RPM but the abilty to be there for any length of time with high power levels.

Edelbrock only has the RPM for the Magnum engine. MoPar has the M1 series in dual and single plane versions, and several types of single plane intakes. Hughes engines has a couple of versions as well.
 
This is a good thread so far..Keep it going...I'm rebuilding my 318, And I'm starting with what I already have, it ran before: I have no idea what the compression will be, how far the pistons are down in the hole, and what cc my 360 J heads are...They do have 1.88 and 1.60 valves...The block has been bored .060 over, and it has no name flat top pistons with 4 valve notches...I'm using the Edelbrock RPM cam and lifters, performer manifold, and some sort of roller rockers, whichever ones I find that are used. lol

It kinda sucks that I have to build this thing in the dark not knowing what I have. But as I go, I'll CC the heads, and check to see how far down the pistons are, check the thickness of the head gaskets..yada yada...Lotta math I gotta do...
 
I noticed in Scamp408's roller rocker thread you said you don't have clearance for 1.6 rockers, BUT, your pistons are far down in the hole. You more than likely have clearance that you do not realize. The valve reliefs are designed to accept larger lifts.
The Zero deck slugs from KB can handle .550 and better.

Knowing how far down in thehole the slugs are along with valve cc relief depth/amounts would be wise. You could be leaving a good deal on the table or left behind in the for sale ad.
 
rumble, thats a very good point you have....I wonder why edelbrock recommends 1.5 ratio with the rpm cam? I think with that cam which is 488/510 is plenty for my 318...how much more would it be with 1.6 rocker arms? do you think that would be too much lift altogether for my 318, with those heads/springs?
 
You would need to make sure your heads can take that much lift. You don't want coil bind or retainer-guide problems either.

that cam would be .520/.544 with 1.6 rockers. That sounds like a lot for a stock J head, but I'm no expert.
 
rumble, thats a very good point you have....I wonder why edelbrock recommends 1.5 ratio with the rpm cam? I think with that cam which is 488/510 is plenty for my 318...how much more would it be with 1.6 rocker arms? do you think that would be too much lift altogether for my 318, with those heads/springs?

My bad, the eyes mis-read and I thought you said "Performer cam" to be used. You can figure out the lift changes by taking the current lift @ 1.5 and dividing it and then taking the answer and multipling it by 1.6 to get your answer.

I think the extra ratio is to much for un-modified J heads. Edelbrock recomends a 1.5 becasue it is stock.
 
My teen-build so far is planned to be.. 396 cube teen with 11.8-1 comp.

67 date coded block,
kb846-60 pistons,
k20-248-4 cam kit,
cast 4 inch scat crank,
I-beam scat rods,
all ARP hardware,
Mildon windage tray,
set up RHS heads from Brian,
fenderwell headers 1 3/4 primaries-3in collect,
gear drive (sounds cool, if I can hear it lol),
904 with 4k stall converter,
4.10 gear,
Runs on corn.. Err, Ethanol. 8)
 
Oh and an M1 intake with 950cfm carb. 8)
 
What LXguy said and;

I do not beileve the Magnum heads or intake will limit RPM in anyway except the prfile of the cam and the springs abilty to control the valve at high RPM's.

Shotpeened rods are a plus but do not hld a key to more power or RPM but the abilty to be there for any length of time with high power levels.

Edelbrock only has the RPM for the Magnum engine. MoPar has the M1 series in dual and single plane versions, and several types of single plane intakes. Hughes engines has a couple of versions as well.
Thanks so far, guys. I was thinkin a good single plane, like M1 might work better at 6,500 +.? One question is, described crank,rod and piston combo should live at ? rpm. ? Haven't been able to locate,CA. guy ,that specializes in Thermoquads.ateam.:glasses9:
 
The 268S cam is a great choice, but small port heads perform better with single plane intakes. Think stock 273 4bbl, marine manifolds, Holley street dominators, Edelbrock streetmasters, or a real find, the torker 318.

IMO at least, I just have gone dual plane to single plane so many times, and said WOW!

the truth is the stockers dont have enough plenum for a good turn

How good (or bad) does this manifold look?
homemade4bbl.jpg

It was a standard (small port) 2bbl manifold that was milled out and had a 4bbl carb flange attached to it. It was never given a decent run as the the only motor is was ever run on had a faulty carb, cam that wasn't dialed in properly, and rings that weren't bedded in properly either.

Vb, this build of yours is coming along very nice. IMO, I'd go for as much compresion as pump gas will allow. The cam is big enuff to use a good ratio.

what do you reckon the max static comp my combo will be able to stand (on pump gas) would be? Our best pump gas is 98,(ron) but a mate was telling me at the pub the other night that US octane ratings on gas are in fact the AKI which is 4-5 points lower the the ron. Is this correct?
 
Thanks so far, guys. I was thinkin a good single plane, like M1 might work better at 6,500 +.? One question is, described crank,rod and piston combo should live at ? rpm. ? Haven't been able to locate,CA. guy ,that specializes in Thermoquads.ateam.:glasses9:
If it gets short blasts of that RPM, yea, I'd be OK with a once in awhile 6500+ RPM finish line run. The issue at hand is actuall total power/torque vs. the stock rod when dealing with the cars weight and intended purpose.

While stock rods are forged and preety good, I really would not push them to hard or to long under alot of power/stress. New rod can be had for very reasonable prices with handling abilites of 750 HP. For under $600, it's a screaming deal.
Unless your can is sizeable and the heads abilty is very good, your really done making power by 6500. The M1 single is fine as is the Edelbrock victor and super Victor for that RPM and higher.
Try Thermoquads.com if your Ca. guy can't be found.

How good (or bad) does this manifold look?
homemade4bbl.jpg

It was a standard (small port) 2bbl manifold that was milled out and had a 4bbl carb flange attached to it. It was never given a decent run as the the only motor is was ever run on had a faulty carb, cam that wasn't dialed in properly, and rings that weren't bedded in properly either.



what do you reckon the max static comp my combo will be able to stand (on pump gas) would be? Our best pump gas is 98,(ron) but a mate was telling me at the pub the other night that US octane ratings on gas are in fact the AKI which is 4-5 points lower the the ron. Is this correct?

I don't know what to say about the manifold, I'd like to hold it before I made a comment. It's truly amazing what wonderful things can be done by backyard guys with old equipment modified. It can also be equal in horror.

Here in the U.S.A. 93 is the best you can get in many states, but not all states. With 93, a 10-1 iron head 11-1 aluminum headed engine is OK.
The differences I forget and I would have to brush up on. I don't remember what your method would convert to.

Though I see it every time I pump gas into the vehicles, I just can't remember what it sez on the side of the pump exactly. I think it says ROn + something something something. I'll find out later when I go out later.
 
That intake looks cool in terms of workmanship. But if you're out to make power, the workmanship went into making the 4bbl attach. Not power. The runners are flat, the turn from plenum to runner is 90°, and the floor of the plenum is shallow and flat. 90° truns suck. Partially mixed fuel will come out of suspension and puddle in the plenum and the roof becomes a big turbulent mess where typically the best smoothest flow should be. I would say if your intention is to use it, I'd suggest epoxying the center of the floor and shaping it to turn the air better, adding pcs to help divide teh plenum as the ports are entered, add about 1.5" of height to the carb pad and put a much more generous radius on the transition from carb baseplate to port roof. The down side is, you do all that, you still only have a small cross section port. So a smaller engine will need to rev to use it and a larger engine will be out of breath early.
 
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