360 motor help

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jerrygriffin

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I have purchased a 78 Dodge Magnum 360 motor and need to have information on the heads. Can anybody tell me what this motor might have and what options are for better flow? Also, what lift cam can you get by with using stock springs? This motor is not installed, and I am getting ready to build it. Best piston for tight budget and street performance?
Thanks,
 
It will probably have #4027596 heads on it but they also could be #4071051. Basically all of the 360 LA heads have the same port shape and valve size. The #308 (last 3 numers of the casting number) head would be the exception on the port shape. The later heads like the ones on your 360 will have a little hump in the exhaust port floor because of the AIR injection ports but this is so minor that it really doesn't effect performance.

With stock valve springs I would limit the lift to .480 but I have seen they can take as much as .500 lift and not bind. The stock spring should though be replaced with anything over .450 for reliability and performance sake. Valves springs are reasonable priced campared to some of the other thinks on the motor. If the motor has some mileage on it you will want to pull the springs and clean the valve stems above the guides. If you don't do this the first time you light the motor with the added lift and there is any deposits or varnish on the stem it will wipe out the valve seal.


Chuck
 
Take a look at mymopar.com

They have a complete list of head casting #'s that should tell you what you got. One of the most informative web site I have found for such info. Click on the downloads section.
Most likely you have casting #4027569 on your heads.. will have 1.88 & 160 valves. from what I understand factory heads range as follows

X heads Origional 340 are most sought after
915 casting J heads are second
 
The casting number on mymopar.com is incorrect, they list it as 4027569, the 6 and the 9 are backwards it should be 4027596. Even thought that site has a lot of info I have found many mistakes so it is hard to tell which is useful and which is not.

Chuck
 
jerrygriffin;

Greetings! I have had 2 Magnums. 1 a 360 and 1 a swap from 318 - 400. Both '79's. The Current big block is my daily driver.

Your question on heads is about flow potentail and power making abilty's. Depending on what your doing to your ride, the stock heads will carry you well for daily driving and light strip. The cars weight is more of a problem for performance potential.

IMO, the best way to rebuild your heads with more perfromance in them is just to have the decks straight, multi angle valve job w/back custock valves and the valve springs to match the cam. DO NOT SKIMP HERE! Valve springs are cheap. Damage that comes from them isn't!
This will be a great little bit of work for what you describe.

You need not look for the older heads. Your will do just fine.

Speaking of further upgrades, on pistons. 2 manufactures come to mind. Theres;

1; Keith Black (KB) pistons. I have used a set of the KB 107-+.030 larger overbored size. These are absoultley fine. There $189 without rings. The piston lacks the Durasheild coating of the piston below. But it is not a problem. Comp ratios are a tad higher for this zero deck piston. The range is 9.8 - 10.9-1. Your large chambered head will come in @ 9.8-1 with a Fel_pro head gasket @ .039 thick.

2; Federal Mougal pistons. They have a set w/rings in the summit catolog for a decent price. $265. Head cc dependent, they fall inbetween the ratios of approx. 9.25 - 10.0-1. They have been recomended by Larry Shepard, McCandles and Dick Landy. MoPar Performance also uses these in there create engines and short blocks. I have a short block. No piston problems.

I would not exceed 9.5-1 with a small cam. Ethier piston has worked excellent for me and both are priced very well for a budget minded build.
 
rumblefish360 said:
jerrygriffin;

Greetings! I have had 2 Magnums. 1 a 360 and 1 a swap from 318 - 400. Both '79's. The Current big block is my daily driver.

Your question on heads is about flow potentail and power making abilty's. Depending on what your doing to your ride, the stock heads will carry you well for daily driving and light strip. The cars weight is more of a problem for performance potential.

IMO, the best way to rebuild your heads with more perfromance in them is just to have the decks straight, multi angle valve job w/back custock valves and the valve springs to match the cam. DO NOT SKIMP HERE! Valve springs are cheap. Damage that comes from them isn't!
This will be a great little bit of work for what you describe.

You need not look for the older heads. Your will do just fine.

Speaking of further upgrades, on pistons. 2 manufactures come to mind. Theres;

1; Keith Black (KB) pistons. I have used a set of the KB 107-+.030 larger overbored size. These are absoultley fine. There $189 without rings. The piston lacks the Durasheild coating of the piston below. But it is not a problem. Comp ratios are a tad higher for this zero deck piston. The range is 9.8 - 10.9-1. Your large chambered head will come in @ 9.8-1 with a Fel_pro head gasket @ .039 thick.

2; Federal Mougal pistons. They have a set w/rings in the summit catolog for a decent price. $265. Head cc dependent, they fall inbetween the ratios of approx. 9.25 - 10.0-1. They have been recomended by Larry Shepard, McCandles and Dick Landy. MoPar Performance also uses these in there create engines and short blocks. I have a short block. No piston problems.

I would not exceed 9.5-1 with a small cam. Ethier piston has worked excellent for me and both are priced very well for a budget minded build.
Click to expand...

Many Thanks. I have a 72 Dart Swinger 318 that runs very nice, but want a little more street performance. The 318 has been bumped up a little with Hooker Headers, Edelbrock performer intake and cam, and 650 double pumper. It runs well, and is in very good condition, having been rebuilt, but I want more cubes. I will want to sell the 318 without the intake. Any idea of it's value or marketability? I have done only bowties up to this point, so I'm a Mopar neophyte.

Thanks for your help!
 
rumblefish360 said:
jerrygriffin;

Greetings! I have had 2 Magnums. 1 a 360 and 1 a swap from 318 - 400. Both '79's. The Current big block is my daily driver.

Your question on heads is about flow potentail and power making abilty's. Depending on what your doing to your ride, the stock heads will carry you well for daily driving and light strip. The cars weight is more of a problem for performance potential.

IMO, the best way to rebuild your heads with more perfromance in them is just to have the decks straight, multi angle valve job w/back custock valves and the valve springs to match the cam. DO NOT SKIMP HERE! Valve springs are cheap. Damage that comes from them isn't!
This will be a great little bit of work for what you describe.

You need not look for the older heads. Your will do just fine.

Speaking of further upgrades, on pistons. 2 manufactures come to mind. Theres;

1; Keith Black (KB) pistons. I have used a set of the KB 107-+.030 larger overbored size. These are absoultley fine. There $189 without rings. The piston lacks the Durasheild coating of the piston below. But it is not a problem. Comp ratios are a tad higher for this zero deck piston. The range is 9.8 - 10.9-1. Your large chambered head will come in @ 9.8-1 with a Fel_pro head gasket @ .039 thick.

2; Federal Mougal pistons. They have a set w/rings in the summit catolog for a decent price. $265. Head cc dependent, they fall inbetween the ratios of approx. 9.25 - 10.0-1. They have been recomended by Larry Shepard, McCandles and Dick Landy. MoPar Performance also uses these in there create engines and short blocks. I have a short block. No piston problems.

I would not exceed 9.5-1 with a small cam. Ethier piston has worked excellent for me and both are priced very well for a budget minded build.
Click to expand...
Are the KB pistons you have for sale? I couldn't quite understand your message on these. Are these Hyperutectic or Forged?
Thanks.
 
I think you need to read it again with some coffee. I mearly pointed out the pistons.
I'm not a dealer. LOL. The pistons are Hyper-U. There out of the Jegs/Sumitt catologs.

On the 318, if you can sell it, a long block is about $100 - $150. Proof of it being rebuilt with reciepts and parts list will increase it's value some. But the 318 can be hard to get rid of. It has a lack of respect and performance image.

OH, No need to quote me in reply.
I also understand doing the Chevy thing. Though it has been 20 years, I still help a fella out around here with there bow tie from time to time.
 
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