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Discussion Starter · #1 ·
Hi I am planning a performance upgrade for my 75 Dart Sport with a 318 and I need some advice. I havnt done any engine mods yet, but I did have dual exhause installed. I am thinking of swapping the stock heads for the late 80's "302" heads, putting in a 340 cam, a 340 4 barrel manifold, with around a 600 cfm carb. I am also putting in headers. Now is there anything about this setup that would go wrong for some reason, or something that I dont know about. Also what sort of power boost would that give my car? I'm a daily driver and I don't want to lower my mpg too drastically, but the reason im planning this is for a power increase.
 

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Hi CaleFox,

Your plans sound good to make some good power. However you might want to look for a stock 318 4bbl intake manifold or an older Edelbrock Streetmaster 318 aluminum intake. For the most part the 318 heads have a smaller intake port than the 340 and 360 heads for most years. So the intake manifold will fit however it won't work properly if the ports are different sizes.
I am not sure about the "302" castings or the late 80's castings though or you can always match the ports on the heads to the intake too. Just something to look out for.

Hopefully someone can answer this a little better than I can. Good Luck with it.
 

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Welcome to the board.

I would suggest more cubic inches such as a 340 or 360 if you are looking for better power. 318 is a great engine but switching to a bigger cam and heads will really hurt low RPM performance. Been there, done that!
 

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I'm with six-pack on the cubic inch deal, but if cash is a problem and you have to keep your 318, then I recommend the Edelbrock Performer intake and cam kit along with their 500cfm carb. If you want to swap heads, then a set of 340/360 heads will be the way to go. I've read that the 1985-up 318/360 swirl port heads flow pretty well. If you end up swapping heads than you can use a 600cfm carb. I wouldn't go to crazy on the cam since were only dealing with a 318..you may want to call some cam manuf. and get their advice.
 

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Discussion Starter · #5 ·
The truth is, I am on a budget, so the chances of getting a new edelbrock performer are pretty slim. I read somewhere that the 340 cam hase higher lift and duration than the 360. If this is true, than maybe a 360 cam would be more suited for a 318. Thanks for the advice guys.
 

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Bottom line is you have to put better heads on that 318....those small port 2bbl. heads won't work with a 340 grind cam and a 4bbl. carb. You can find a set of 360 heads at a junkyard and maybe even a 4bbl. intake. Mid-late 80's swirl port heads are a good choice along with a 340 or early 360 4bbl. intake. Remember even 318 4bbl. engines had 360 heads on them from the factory.

Can I suggest a good book? Get "How To Hot Rod Small Block Mopar Engines" available at Amazon.com. I basically got it for the part interchange information..this way you'll now what casting numbers to look for when getting heads, intakes, etc. for your engine.
 

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Dodgevanman said:
Can I suggest a good book? Get "How To Hot Rod Small Block Mopar Engines" available at Amazon.com. I basically got it for the part interchange information..this way you'll now what casting numbers to look for when getting heads, intakes, etc. for your engine.
I agree. Its a great book, I used that in building my new 360 and it really payed off parts wise. It even gives you certain combinations of engines and the approximate power they will produce. However it is a bit vague on assembling the motor if it is your first time as it was mine when I built about a month ago.
 

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Tell you what I ended up doing with my Mirada after putting a 340 cam and factory 360 intake and ThermoQuad on it.
I advanced the cam 4º and re-installed the factory 2bbl. car never ran so good.

I still remember factory police cars in 85 being 318 4bbl Quadra jets, when we were doing the pre Delivery Inspection we would always road test them, when I got out to my turn around spot on the higway one of the other tech was right behind PDI'ing a new 5th Ave(318 2bbl) we raced back from a roll and he kicked my ass!!!

You don't always need 4bbl for more performance!
 
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