Author Topic: 318 Build With Exhaust Manifolds; Advice Needed  (Read 194 times)

Offline Road_Runner

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318 Build With Exhaust Manifolds; Advice Needed
« on: October 14, 2017 - 12:28:10 am »
So I've come full circle with the Barracuda and now just want a fun to drive pony car with decent 300ish HP 350ish TQ.  These aren't  hard targets, just something to shoot for.  The original 318 motor was rebuilt not that many miles but probably several years before I bought it so what I'm thinking is this:

Swap the cam for something more performance oriented. Car has a 904 and 2.94(?) Highway gear which I'm inclined to swap for a 3.23 to help the car get moving from a stop.

Have the 302 heads I have worked on to flow more, maybe opened up to 340 size intake

Run either LD4B for 318 ports or LD340 if I go with the larger intake ports

650 Ede Thunder carb

Lastly, run either 73 340 log style exhaust manifolds, 70 style HP, or larger early 80's 360 manifolds.  I know the 360 manifolds flow the most but for this build will a 30 over 318 notice the difference?

Again, I want quick but not racecar fast and if it still got around 20 mpg on the highway I wouldn't be too unhappy.  So for those that have built any similar motors I'd appreciate your thoughts and advice.

Thanks, Jim
1970 383 Roadrunner Tor Red
1973 318 Barracuda Mist Green
2014 Mustang GT/CS Convertible All Black




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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #1 on: October 14, 2017 - 01:20:44 am »
Another good option is the 5.9 Magnum manifolds.... Supposedly they flow better than any other small block manifolds & they fit B & E body....
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
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Offline Road_Runner

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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #2 on: October 14, 2017 - 01:31:15 pm »
Another good option is the 5.9 Magnum manifolds.... Supposedly they flow better than any other small block manifolds & they fit B & E body....

I think we're talking about the same manifolds, they were calling 360s 5.9 liters by the early 80's and the 81-82 were slightly larger than the later years.  I have heard that there could be clearance issues just not sure with what.  I know that some here have run them so hoping they'll comment on any fitment issues.  One thing for sure, using these would require custom down pipes.

Later, Jim
1970 383 Roadrunner Tor Red
1973 318 Barracuda Mist Green
2014 Mustang GT/CS Convertible All Black


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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #3 on: October 14, 2017 - 03:19:00 pm »
82 360 is a log style... 92 looks like this..
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
RM21H9E 69 Road Runner Coupe R4 Performance Red, Sold...
5H21C  65 Falcon 2 dr Wagon... Dog Hauler...

Offline Road_Runner

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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #4 on: October 14, 2017 - 10:06:54 pm »
82 360 is a log style... 92 looks like this..

Hmmm, my 360 manifolds look very similar to those but from what I understand have a slightly larger inside diameter.  Had to look everywhere to find a pair, but eventually did.  Chyco and others here said they were the hot ticket manifold wise, but i seem to remember some mention that there could be interference fitting on an e body since they were designed for Dakota's, etc. Later, Jim
1970 383 Roadrunner Tor Red
1973 318 Barracuda Mist Green
2014 Mustang GT/CS Convertible All Black

Offline Road_Runner

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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #5 on: October 14, 2017 - 10:40:18 pm »
So I must have 91-92 360 manifold not 82, I bought them a few years ago so sorry about the confusion!

Still need input on the overall build and HP/TQ targets.

Thanks, Jim
1970 383 Roadrunner Tor Red
1973 318 Barracuda Mist Green
2014 Mustang GT/CS Convertible All Black

Offline Road_Runner

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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #6 on: October 16, 2017 - 09:06:01 am »
I've been away for a while myself but things are kind of slow around here right now!  Any of our engine builders have any advice about my proposed Build?

Thanks, Jim
1970 383 Roadrunner Tor Red
1973 318 Barracuda Mist Green
2014 Mustang GT/CS Convertible All Black

Offline Beekeeper

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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #7 on: October 16, 2017 - 09:40:10 am »
I can't comment on fitment but I like the idea of using the 92 manifolds. I wouldn't mind finding a set of those and a set of the 308 heads that those were normally bolted to. I'm told the 308 heads were one of the best iron heads so it makes sense that the manifolds would also flow well.

A lot of guys fled to the other site. I checked it out but it seems that the other site is all about the hard core purist while this site seems to contain members who aren't afraid to deviate from original.

Offline Road_Runner

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Re: 318 Build With Exhaust Manifolds; Advice Needed
« Reply #8 on: October 17, 2017 - 10:09:44 pm »
I can't comment on fitment but I like the idea of using the 92 manifolds. I wouldn't mind finding a set of those and a set of the 308 heads that those were normally bolted to. I'm told the 308 heads were one of the best iron heads so it makes sense that the manifolds would also flow well.

A lot of guys fled to the other site. I checked it out but it seems that the other site is all about the hard core purist while this site seems to contain members who aren't afraid to deviate from original.

The same folks who recommended the 360 exhaust manifolds also recommended the 308 heads, except in some cases like my proposed  318 build where the closed chamber  of the 302's help raise the compression ratio for a stock 318, but don't flow like the 308s without a bunch of work.  If I end up changing pistons I'll definitely consider the 308s too.
1970 383 Roadrunner Tor Red
1973 318 Barracuda Mist Green
2014 Mustang GT/CS Convertible All Black