360 Crank in a 318?

[73restomod]

Here are some links for 318 builds that may be a little optimistic, but still points to its potential.

http://www.hotrod.com/howto/113_0304_318_small_block_build/viewall.html

http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/viewall.html

[Chryco Psycho]

I would use a little of both builds but lean more to the Hot rod build , I would swap the pistons & use the 360 / 308 heads & gain compression that way with less porting time in the heads . The 800 CFM TQ would need some serious tuning on a 318 but shows the potential of even the stock induction system !!  With the hot rod build most people would not have a fresh short block avaialble so pistons & rings would be new anyway Most people doing the Mopar Muscle build would use wrecker Magnum heads not spend for new castings so you would be machining the heads so trim the guides & use a cam with more lift .
 I did a 340 a few years back it was running well but he wanted more power so I ported & machined a set of the 308 swirl castings , removed X castings & bolted the 308 heads on , we dynoed on Thursday , swapped heads on Sunday & redynoed Tuesday , with no other changes we gained 41 RWHP or approx 60 gross HP . the 318 & 340 are so close it is crazy , just a slightly larger bore . the big difference was just the compression ratio , large port heads , cam , intake & carb on the 340 , change those 5 things and the 318 will run just as hard

[Road_Runner]

Here are some links for 318 builds that may be a little optimistic, but still points to its potential.

http://www.hotrod.com/howto/113_0304_318_small_block_build/viewall.html

http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/viewall.html

Thanks for the links.  I read both & have them bookmarked for later refrence!

Later, Jim

[Road_Runner]

I would use a little of both builds but lean more to the Hot rod build , I would swap the pistons & use the 360 / 308 heads & gain compression that way with less porting time in the heads . The 800 CFM TQ would need some serious tuning on a 318 but shows the potential of even the stock induction system !!  With the hot rod build most people would not have a fresh short block avaialble so pistons & rings would be new anyway Most people doing the Mopar Muscle build would use wrecker Magnum heads not spend for new castings so you would be machining the heads so trim the guides & use a cam with more lift .
 I did a 340 a few years back it was running well but he wanted more power so I ported & machined a set of the 308 swirl castings , removed X castings & bolted the 308 heads on , we dynoed on Thursday , swapped heads on Sunday & redynoed Tuesday , with no other changes we gained 41 RWHP or approx 60 gross HP . the 318 & 340 are so close it is crazy , just a slightly larger bore . the big difference was just the compression ratio , large port heads , cam , intake & carb on the 340 , change those 5 things and the 318 will run just as hard

Hi Chryco,

A couple of questions: I have a set of 302 heads, with some reasonable porting will these work or are the 308 heads really necessary for this level of HP.  I would also consider RHS heads.  I do have an 800 CFM TQ ready to use but most performance manifolds are for square bores only.  And are you saying stay with the std stroke or with the 360 crank like I originally was asking about.

Thanks, Jim

[Chryco Psycho]

I was really just commenting on the magazine builds , logically some of it makes no sense , in the first build they cut corners on spending but buy brand new heads the second built they used a fresh short block with low compression , neither is a realistic scenerio for the average builder , would you reuse a tired short block ... no , if you do the short block would you use low comp pistons ... no !! I f you were doing a low buck 318 build would you buy new head castings .... no , I would score a used set from a wrecker for $20 / Head so you would machine the heads & therefore trimming to guides would not limit cam choice , Comp must be paying Huge kickbacks so now magazine build ever uses anyone elses cams too !!
 Can you make power with just a 318 .... Yes , would I do ti they way the mags did it ..no
 If you are rebuilding the short block why not  stroke it , not a lot but it will pay off , lighter pistons , slightly shorter but still they will last OK , removing weight from the rotating assy helps . Good breathing in & out , if you can get a set of 308s I would do that , it saves a bunch of work , the article proves the 302 will work too , I know there is a lot of potential in these castings , some intakes are dual pattern & will accept the TQ carb , be prepared for some work though , they are tough to get tuning parts for & the article mentions a lot of time spent tweaking the TQ . I am not sure if the RHS heads look stock  but for the cost may well work out cheaper then rebuilding & porting factory heads . Pick a Good cam you can get a lot of lift free with no penalty in drivability , you can always use PRW 1.6 ratio Stainless rockers just make sure the piston to valve clearance is good . , The LD 340 or RPM AIR GAP are the best intakes available . Although it only gained 20 HP from a stock iron intake !! With a few more $$ invested you should be able to get more than 400 hp !

[Road_Runner]

I was really just commenting on the magazine builds , logically some of it makes no sense , in the first build they cut corners on spending but buy brand new heads the second built they used a fresh short block with low compression , neither is a realistic scenerio for the average builder , would you reuse a tired short block ... no , if you do the short block would you use low comp pistons ... no !! I f you were doing a low buck 318 build would you buy new head castings .... no , I would score a used set from a wrecker for $20 / Head so you would machine the heads & therefore trimming to guides would not limit cam choice , Comp must be paying Huge kickbacks so now magazine build ever uses anyone elses cams too !!
 Can you make power with just a 318 .... Yes , would I do ti they way the mags did it ..no
 If you are rebuilding the short block why not  stroke it , not a lot but it will pay off , lighter pistons , slightly shorter but still they will last OK , removing weight from the rotating assy helps . Good breathing in & out , if you can get a set of 308s I would do that , it saves a bunch of work , the article proves the 302 will work too , I know there is a lot of potential in these castings , some intakes are dual pattern & will accept the TQ carb , be prepared for some work though , they are tough to get tuning parts for & the article mentions a lot of time spent tweaking the TQ . I am not sure if the RHS heads look stock  but for the cost may well work out cheaper then rebuilding & porting factory heads . Pick a Good cam you can get a lot of lift free with no penalty in drivability , you can always use PRW 1.6 ratio Stainless rockers just make sure the piston to valve clearance is good . , The LD 340 or RPM AIR GAP are the best intakes available . Although it only gained 20 HP from a stock iron intake !! With a few more $$ invested you should be able to get more than 400 hp !

Thanks Chryco, this is really sound advice.  If I decide to keep the original motor (and I still have to confirm it is the original motor but 90% sure it is), this will be the route I take.  I've had a hard time identifying / finding 308 heads on Ebay, etc. but I'll keep an eye out.  The stroke of the 360 crank in the 318 sounds like a good compromise and still pushes the 318 to right at 350 c.i.  When I start the build I may get a specific cam recommendation from you based on the other parts I've gathered.  The only part of the build I'm still waffling on is the exhaust.  I'd like to stay with std 340 or Hipo manifolds for the stock look, but if I build the rest of the motor to a point it no longer works with manifolds I'll go the TTI or Dougs headers route.

Thanks again, Jim

[dodge freak 2]

People can be funny about what came stock in the car. Number matching is something different but for a 318 stock engine, not sure it really matter for resale value.

I went with a 340 block since my 318 block was already .030 and one cylinder bore was chip down low--broke a rod long ago. I just couldn't see buying another 318 block and building it up when for $600 I found a 340 without a forged crank and exhaust manifolds.

I cleared $100 selling the 1972 intake and got a factory forged crank for $150 to my door-was a great deal, clean up at .010 over--the seller like my old posts on another Mopar forum.

If you ever go to sell the engine, the 340 will bring in more $$ then the 318-regardless the HP it makes, IMO

The 360's are great engines also.

I guess thou if the numbers do match, sure since you have a good block, build the 318, stroking it a bit would help. Heads, ugh..those 308's can be hard to find not crack. Maybe some are still out there ?

The person I got my MP heads based on the 308 castings only was selling it since his Dart came with a 318 and it had a 360 short block in the trunk with those MP heads. He told me since the engine bay was empty, he didn't want to drop the 360 in there since it came new with a 318 (I had a hard time not laughing as I paid him$300 for those heads) The laugh was partly on me cause I past up his good 360 short block since it had Hyper pistons, only to later on get a 340 short block with hyper pistons, lol 

I went with the 340 HP exhaust manifolds with crimp bent exhaust pipes since it was cleaner-not very expensive and I was sick of leaky headers but when I took the car to the strip, I could not break in to the 13's--came very close. TTI headers would had did it but those were like $600-$700 vs the $400 I got the HP manifolds for.

Yeah build the 318 and get 10 to 1 compression. Heads ? Well you never know what you can find on Ebay-how I scored those MP heads and they were 30 mins away from my home. Ported 360 heads-like the easier to find 1973-74 heads might be fine ? You pay more for the X heads and many are worn out-sunk valve seats from too many regrinds. The 71 and later heads came with 1.88 valves and 2.02 valves solves the sunk valve problems--least on the intake. I feel the 2.02 intakes are worth it but this is where the lager 340 bore does help more over the 318 but you will be opening the 318 up .030 so that help letting the 2.02 flow more.

[Road_Runner]

I went with a 340 block since my 318 block was already .030 and one cylinder bore was chip down low--broke a rod long ago. I just couldn't see buying another 318 block and building it up when for $600 I found a 340 without a forged crank and exhaust manifolds.

I went with the 340 HP exhaust manifolds with crimp bent exhaust pipes since it was cleaner-not very expensive and I was sick of leaky headers but when I took the car to the strip, I could not break in to the 13's--came very close. TTI headers would had did it but those were like $600-$700 vs the $400 I got the HP manifolds for.

It sounds like I'm looking at going a similar route with the Barracuda as you did with your car.  You know I'd like to think I could get into the 13's even with the 318, but I may be overly optimistic since I'm really not willing to sacrifice driveability for outright HP.  I've got the Roadrunner for that.  the 318 in it now is running fine so I have some time to gather parts & make plans but this is helpful since I'd like to decide once & for all and just get going in one direction with the car.

Later, Jim

[dodge freak 2]

That little 340 is very street friendly, idles at 700 in gear (900 out), pulls good to 6,300 and my fuel system is just a Cater HV mechanical fuel pump-if it had a nice electric fuel pump and 1/2 inch fuel line from the tank it sure would help out, might well be running dry or it pull to 6,500 plus-with a hyd cam.

Cam is an older Crane Commando , 226-230 @ .050 on 110 lbc around .470 lift.

It does have those nice MP cylinder heads with 2.02 intakes and Erson iron adjustable rockers, the factory stamp rockers usually aren't a true 1.5 ratio and its harder to set the pre load just right..a 1/4 to 1/2 turn from loose I have the rockers set.

I believe the MSD 7 al ignition and MSD E curve dist helps burn more of the fuel and the timing is steady since there is no springs for the timing advance, its done electronically..has NGK non resistor racing spark plugs- under $3 a plug from Summit..I replace them each season, the high energy spark "eats" the metal on the plugs 

And yeah, having two 500 cfm Cater carbs on an older dual quad intake helps out, with a single Holley 750 dp it didn't idle just as nicely and I swear it makes a little more HP even thou Edelbrock claims on the Chevy dual carb set up its down on HP from a single carb.

The 3.91's and 3,000 stall  really aren't that bad, up to 55 mph it feels just "right" after that the rpm's do build but with a fairly quiet exhaust its doable. Around town in the 45 mph zones the gearing feels perfect to even not quite enough..2nd gear would pull even better with 4.30 gears but then freeway driving past 60 mph would be even worst. 

My set up just isn't cheap to duplicate--mine "just happen" over the years..every year I did something and over 10 years later on I found myself with a very nice ride, IMO 

[Road_Runner]

My set up just isn't cheap to duplicate--mine "just happen" over the years..every year I did something and over 10 years later on I found myself with a very nice ride, IMO

I'm sure I'll keep wrenching on mine as long as I own it, too.  I just need to pick a direction and go with it so I can begin making some serious progress.  If I'm keeping the 318 I'll probably do some incremental mods until I can pull the engine and do it right, but if I decide to go with the 340 I'll just drive the 318 as is until I'm ready with the new motor.  If I decide to forget 'originality' I'm tempted to go pistol grip 4 speed too.  I've got most of the parts to do it with a factory look which is my main goal, to keep it stock appearing even if it isn't.

Later, Jim