318 build

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ryan1964

ryan1964

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Ok so I'm build a 318 stock bore flat top pistons new bottom end either a 454 lift cam or a 480 lift summit grind 4 speed is putting 360 J heads on it going to help it or hurt it
 
ryan1964 said:
Ok so I'm build a 318 stock bore flat top pistons new bottom end either a 454 lift cam or a 480 lift summit grind 4 speed is putting 360 J heads on it going to help it or hurt it
Click to expand...
Flat top as in stock or (near) zero deck aftermarket ? Hopefully the second one.
What rear gears ?

Got links to the cams or just copy paste their specs here.
 
If you got the cr I'd go with the 360 heads.

You'll probably get a mix of opinions on it, to me 360 heads are a decent performance head for a 318.
 
Switching to 360 typically drops compression a point or more. Older 318s were higher in compression. Cleaning up the ports on the 318 would be ideal rather than giving up compression.
 
Mopar44134 said:
Switching to 360 typically drops compression a point or more. Older 318s were higher in compression. Cleaning up the ports on the 318 would be ideal rather than giving up compression.
Click to expand...
You can mill the 360 heads by like .030-.040" I forget exactly and keep at least stock cr.
 
273 said:
You can mill the 360 heads by like .030-.040" I forget exactly and keep at least stock cr.
Click to expand...
Absolutely, and if you do, remember to have the intake surface milled as well. The machine shop should know the formula.
 
It’s not that simple. What you have to do is cc the combustion chamber of the head your using and cc the bore with the pistons your going to use at top dead center and figure your compression ratio that is your static compression ratio. Then with that AND your cam specs go to wallace racing calculators and figure out your dynamic compression ratio.

7:1=super doggy
8:1=still doggy
9:1=you will end up wanting more
10:1=now your getting somewhere
11:1=you better have an awesome engine
Builder and a spot on tune cause
Your coming into detonation
territory with pump gas.


Now to answer your question what year 318 and what heads does it have now?
 
ch1ll said:
It’s not that simple. What you have to do is cc the combustion chamber of the head your using and cc the bore with the pistons your going to use at top dead center and figure your compression ratio that is your static compression ratio. Then with that AND your cam specs go to wallace racing calculators and figure out your dynamic compression ratio.

7:1=super doggy
8:1=still doggy
9:1=you will end up wanting more
10:1=now your getting somewhere
11:1=you better have an awesome engine
Builder and a spot on tune cause
Your coming into detonation
territory with pump gas.


Now to answer your question what year 318 and what heads does it have now?
Click to expand...
1970 and pretty close to zero deck
 
Compression police are here now waiting for the displacement police :)
 
post up some cam #'s and let's see what's what.

with a 318 i'd err toward the smaller cam, especially if you don't have the compression, gears or stall to back it up.

shorter duration and tighter LSA with an early IVC will keep what little dynamic compression you have.

i see 480 lift which makes me think you're looking at a popular 480/280 cam, which is really what you don't want for a 318 unless you're pressing at a true 10:1 and backing it with a 4spd or a decent amount of stall.
 
first person to mention going with a 360 gets pistol whipped.

*taps ear piece*

oh. uh huh. okay, well looks like we have a winner.
 
I’d have to hear a realistic assessment of what the finished result is hoped to be before recommending 318 or 360 heads.
The milder the combo, the more I’d lean towards staying with the 318 heads.

I know of a few 318’s where 360 heads got swapped onto them, without the details being sorted out, that ended up pretty doggy.
 
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