69 318 with 302 heads?
#2225952
01/02/17 11:08 PM
01/02/17 11:08 PM
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Joined: Jan 2005
Posts: 259 Ohio
ScottG
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Hi Guys, I have a 1969 Dart GT 318 with 70K original miles on it. I put a 68 340 intake on it with a 625 AFB. I also have dual exhaust and a Mopar Performance electronic distributor installed. I want to get some more HP out of it, with more low end torque. I picked up a set of 302 heads today. My question is should I put bigger valves in the heads and what cam should I use. I don't want to do anything to the short block, just bolt on some more performance. Any suggestions would be appreciated. Thanks Scott.
1966 Coronet 440 conv. original Mauve metallic, with white top and interior. 1971 360, J heads, 625 AFB, 340 cam, intake, and manifolds. With 3.23 SureGrip.
1969 Dart GT: B5 Blue, White top, 318, With A/C
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Re: 69 318 with 302 heads?
[Re: buildanother]
#2225967
01/02/17 11:26 PM
01/02/17 11:26 PM
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Joined: Jul 2007
Posts: 11,836 Florida
mopar346
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Let me tell ya about fat chicks!
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I would say, that car's a beauty, don't go too nuts. I agree, very nice.
Careful, your character's showing!
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Re: 69 318 with 302 heads?
[Re: ScottG]
#2225992
01/02/17 11:52 PM
01/02/17 11:52 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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Circle Track
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Lincoln Nebraska
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with more low end torque. when you get the cyl psi finalized (heads/cam/cam advanced) I would dial in the dist subsystems for a significant gain
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Re: 69 318 with 302 heads?
[Re: Eggman]
#2226000
01/02/17 11:59 PM
01/02/17 11:59 PM
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Joined: Jan 2005
Posts: 259 Ohio
ScottG
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Don't worry I am not going to go nuts. LOL I still have all of the parts to put it back to stock if I would want to. I just want to see if I can get a little more out of it. Thanks for your replies.
1966 Coronet 440 conv. original Mauve metallic, with white top and interior. 1971 360, J heads, 625 AFB, 340 cam, intake, and manifolds. With 3.23 SureGrip.
1969 Dart GT: B5 Blue, White top, 318, With A/C
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Re: 69 318 with 302 heads?
[Re: ScottG]
#2226075
01/03/17 01:11 AM
01/03/17 01:11 AM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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302 heads aren't worth putting money into. Magnum heads would have been a good bang for the buck.
Are the 302 heads better than the 69 heads? Yep, but not enough better stock for stock to warrant the costs of the gaskets to swap them and putting more money into them to improve performance is worse costwise.
A cam swap would perk either set of heads up though. I like the 340 cam in a street 318 myself.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: 69 318 with 302 heads?
[Re: ScottG]
#2226136
01/03/17 03:04 AM
01/03/17 03:04 AM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
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Unfortunately there isn't any "cheap" way into a performance head upgrade on a LA 318.
The 302 wouldn't be a bad way to go if the heads currently on the motor needed overhauling anyway, but if the current heads have no issues, it's going to be a pretty big expense for minimal gains(unless the 302 heads have a fair amount of work done to them=$$$).
The valve springs on 318's are really quite low pressure, so I would keep the cam selection on the very mild side unless springs are part of the plan. A nice little cam swap in those motors that can be done while still using the OE springs is a 360 2bbl cam. It's quite a bit bigger than a 318 cam, but works with the OE springs, and the lift is low enough not to cause any retainer to seal issues.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 69 318 with 302 heads?
[Re: ScottG]
#2226362
01/03/17 03:33 PM
01/03/17 03:33 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
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The 302 heads actually flow worse than the old open chamber 318 heads or any other 318 head actually. They do have more swirl and closed chambers for a little more compression but the flow will probably make more power in the end so you need to do some upgrades in the flow department or you will not be happy. The magnum heads are better flow, swirl and compression and can easily be disquised, the original valve covers still bolt on, the ex manifolds bolt on and you can redrill the intake bolt holes to keep your original intake. The 1.6 rockers will make it seem as though your cam is bigger to boot. If you just have to run the 302 head put in 360 valves and touch up the ports, bowls and PR pinch a little and run the 360 2bbl cam fast mentioned, grind down the sharp point in the middle of the chamber and unless you run a steel shim head gasket you will lose any compression you gain from the smaller chambers and then some. The only place I can find steel shim headgaskets is in the MrGasket MLS head gasket, I buy one gasket pop the rivets out and the two outer layers become two individual steel shim head gaskets.
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Re: 69 318 with 302 heads?
[Re: HotRodDave]
#2226590
01/03/17 09:18 PM
01/03/17 09:18 PM
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Joined: Jan 2005
Posts: 259 Ohio
ScottG
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Thanks for the info guys. I knew the heads would need to be ported when I bought them. This is something I want to try to do myself. They were only $50 and they were allready pulled from a running motor. So if I mess them up it's no big deal. I don't want to touch the original heads. I have read some articles that if these heads are ported right they can flow really good. So It is a challenge to me to see if I can make them work. I am looking for low end torque with quick responce, should I leave the stock valves or put the 1.88-1.60 in it? I also read to shave .020 off them to keep the compression up. Not trying to do it the cheapest way, this is just a little project I have wanted to try.
Thanks again Scott
1966 Coronet 440 conv. original Mauve metallic, with white top and interior. 1971 360, J heads, 625 AFB, 340 cam, intake, and manifolds. With 3.23 SureGrip.
1969 Dart GT: B5 Blue, White top, 318, With A/C
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Re: 69 318 with 302 heads?
[Re: ScottG]
#2226691
01/03/17 11:01 PM
01/03/17 11:01 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
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I like to put in the bigger valves so I can shape the bowls better, get a better VJ as well as they can flow more.
.020 won't make much difference, probably at least .030 or .040 or more if you end up with a thicker head gasket than the stock steel shims.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: 69 318 with 302 heads?
[Re: ScottG]
#2226695
01/03/17 11:06 PM
01/03/17 11:06 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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If you Googled em I think some good reading would come up. A skim cut would ensure the decks are flat & iirc some 1.88's are a good plan. I have a set I purchased for either 50 or 75 I forget which about 15 years ago. I wanna build a tight quench 318 for a mileage DD. skim cut/new guides/new valves would be completely gone thru (use em & get your moneys' worth out of em). I would home port em especially as I did not realize they were real dogs as is.
live every 24 hour block of time like it's your last day on earth
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