Re: 318 to 390?
[Re: Moparmal]
#1315259
10/09/12 11:02 AM
10/09/12 11:02 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Lets see here... your gonna buy a stroke kit... that part is a wash... why not buy a 360 block and get the added cubes... that would cost about 200 buck more.. cubes are great for the street........ JMO
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Re: 318 to 390?
[Re: MR_P_BODY]
#1315260
10/09/12 11:52 AM
10/09/12 11:52 AM
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Joined: Oct 2003
Posts: 11,702 W. Kentucky
justinp61
I Live Here
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I Live Here
Joined: Oct 2003
Posts: 11,702
W. Kentucky
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Quote:
Lets see here... your gonna buy a stroke kit... that part is a wash... why not buy a 360 block and get the added cubes... that would cost about 200 buck more.. cubes are great for the street........ JMO
Pick up a later roller cam 360 block, everything else costs the same. Plus the larger bore of a 360 will help unshroud the intake valves.
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Re: 318 to 390?
[Re: Chris'sBarracuda]
#1315264
10/09/12 07:18 PM
10/09/12 07:18 PM
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Joined: Jan 2012
Posts: 25 California
Mad Dart
member
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member
Joined: Jan 2012
Posts: 25
California
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Quote:
You might want to think that over carefully..
https://board.moparts.org/ubbthreads/show...rue#Post7384092
This was a 318/390..
Chris..
Unfortunately when a part fails like this it takes out the whole enchilada. This has nothing to do with the 318/390 build at all. I had the same thing happen to a hot 340 I had at 7200 RPM, Was not quite as bad but it did drop a valve, took out a cylinder, broke a pistion fkd up the head, annihilated a Rod. I could only find balled up pieces in the pan and all over the inside of the engine, intake etc. This can happen to any engine when a Valve lets go. I put a 410 Stroker in it and when I fired it off I had quite a few pieces come flying out the exhaust that were stuck in the mufflers.
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Re: 318 to 390?
[Re: Tinmans21]
#1315266
10/09/12 11:16 PM
10/09/12 11:16 PM
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Joined: Jul 2010
Posts: 1,845 Tampa
DusterDave
top fuel
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top fuel
Joined: Jul 2010
Posts: 1,845
Tampa
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Quote:
Idk if this makes a diffrence but the 318 actually came out of a 83 pickup. The motor is on a stand atm. Does anything change with that motor? It really sounds like its a matter of opinion or choice with the 318 vs 360 arguement. I'm going to stick with the 318 an stroke it to a 390 an bore the block .40 over. I'm going to stick with the 318 cuz i have a 383 block sitting soooo buying a 360 would just mean another motor sitting until I can sell it. I may plan on using nitrous for track use only permitting that the motor will handle it. The car will have a A833 for sure an a 8 3/4 axle for sure. Im new to this so any advice is appreciated. I am going to lighten the car as much as possible since it will see the track but i need to keep in mind it will also be a friday night cruiser. Thanks for all the input!!
The '83 318 block is different than the older 318 blocks. The decks are weaker, and susceptible to cracking between the coolant hole and the nearest head bolt hole. I know this, because I was going to use a 1983 318 block to build a 390, and that block had a total of 10 cracks on both decks. They weren't discovered until after several machining operations. Here is a pic of what my engine builder found. Two differences you can see are the head bolt holes going through the deck, and larger coolant holes, both of which weaken the deck. On the older blocks, the head bolt holes are blind and the coolant holes are smaller.
I'm not saying your block WILL have these cracks, all I am suggesting is that you have those decks carefully examined before sinking money into machine work on that particular block. Also, have your machinist check for twist in the block. Seems the '83 blocks in general are on the weak side, which proved to be the case with mine. It was twisted pretty bad. Although my machinist informed me that the cracks could be fixed, I decided to cut my losses and start over with a beefier 1970 318 block that was available to me.
Gone to the dark side with an LS3 powered '57 Chevy 210
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Re: 318 to 390?
[Re: DusterDave]
#1315267
10/10/12 12:44 PM
10/10/12 12:44 PM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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'83 block is a non-roller block. personally, that's the big advantage of building a 318 based stroker over a 360, it's MUCH easier to find a roller cam block for cheap
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 318 to 390?
[Re: dizuster]
#1315271
10/11/12 02:21 PM
10/11/12 02:21 PM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
I Live Here
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I Live Here
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Posts: 16,123
Grand Haven, MI
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Quote:
My point about the 360 vs. 390 was purely cost related. You could get a running magnum 360 cheap. All of the rebuild parts are a wash between the two (gaskets, machining, etc…)
My opinion is that you can buy a 360 magnum motor for the price of a cast 318 stroker crank. So call that a wash dollar for dollar.
But if you're on a budget, I'd MUCH rather have a 360" with a 360 magnum head, then a 390" with a '83 318 smog head any day of the week.
It was more then just the cubic inch difference. Just depends how much money you want to spend…
you can? here core 360 mags go for over $500, and runners are in the $800-1k range, even if they're over 120k miles...318 mags go for about 1/2 what the 360's do...
but yes, I'd much rather have a mag 360 and give up 30CID than a 390 stroker choked with LA 318 heads.
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 318 to 390?
[Re: Tinmans21]
#1315273
10/11/12 07:04 PM
10/11/12 07:04 PM
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Joined: Jan 2003
Posts: 10,088 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,088
Frostbitefalls MN (Rocky&Bullw...
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If you don't open the hood the big block will make it a real sleeper. A LOT more cubic inches stroked, and stock heads with big valves and a little bowl work can flow enough to go over 500 hp. Probably with a hydraulic cam if you like.
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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