318 or 360 Roller Swap

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crackedback said:
Any one that thinks the 318/360 is a dog manifold with a little port opening work has never tested one and seen the results. It ran within 5 hp of an air gap with a lot hotter cam and heads... The intake works fine, he has it and the cam/heads are going to be the choke point.
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RRR & myself have been saying this for years. The OE intake can and will perform really well. Better when it is handled with a grinder for a few minutes on just the port opening.

The heavy weight of the intake isn’t a huge draw back when your in the street just cruising around or having some fun.

The Weiand with its dinky ports works well because of the velocity it keeps. It has its limitations. A well ported Weiand works really well. Just like any other ported intake.
 
You know Rumble. The differences between all these intakes on a 300-400hp engine is so small it's not worth the $ to replace one intake with another if it's a performer/RPM/air gap/LD340/LD4b
That's the likely range the OP is looking for. Spend an hour with a dremel or grinder and the port opening can be the same if it's that big of a deal to you. Sweat over $'s.

The performer 318 with 1hr or less work in the port openings put down 425hp on a 360 vs the air gap at 432hp IIRC

The big 340 port LD340 vs the small port LD4b on a mid 12's 340 auto car.... an incredible .02 et change and no MPH change... HMMMM

I've been around the dyno/track enough to know that the flow and port opening BS of the 340 vs 318 is mostly nonsense and minimal in actual performance. As you point out, what's BEFORE the opening is as important as the opening itself. You know when the Super victor put down a crapload more flow than an air gap. Then you put a SV on a somewhat rowdy 410 inch engine and the poorer flowing Air Gap kicks it's *** from bottom to top.

Same red herring BS as the 741 case bullshit that's been around for years.

The OP has the intake, why waste money on something else... funny how that works for one persons plan and not the other. :)

Other people and magazines will wastefully spend your money faster than anything! LOL
 
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I'm just looking at the combo. Roller 318 with closed chamber heads and 9.2:1 compression vs roller 360 with open chamber heads and 8:1 cr. Assuming no port work, I'm thinking the 318 is the better combo here.

If he's comfortable modding the heads and intake, then yes, it's the 360 all day long. Will the performer bolt on 100% stock and run? Sure. Can you flow nearly just as good with a cheap factory 4bbl? Yep. If budget is an issue here, he may want to know that. The factory piece is good to at least 300hp.
 
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I'd take the oem360 all day every day over the oem318.

Make a cam/spring change, run the performer and it's a 300+ hp engine pretty easily.
 
I have had the stock intake and TQ down to the 12’s. Swap on “Other Intakes” without much gain. Spent tons of time trying to find the magic tune to no avail.

Wish I had my old junk! (Paper work and slips and such....)

It has be unfortunate that life gets in the way of the drag strip. But that’s family! I (almost) can’t wait to get back to the strip. Just for Ha-Ha’s I want to run a TQ again.
 
I always figured a good gear is worth a bunch! 2:73! don't think so unless racing top end. Yes love the TQ, just not smart enough to build/tune them!
 
barbee6043 said:
Yes love the TQ, just not smart enough to build/tune them!
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I'm in the same boat. Lately I've been very tempted to dig into one though. Harms wants $400 to restore one, which is more than I'd like to spend but probably worth it. There are also several sources for remans in the $200-225 range, but who knows what kind of bag of parts you'll be getting.
 
Montclaire said:
I'm in the same boat. Lately I've been very tempted to dig into one though. Harms wants $400 to restore one, which is more than I'd like to spend but probably worth it. There are also several sources for remans in the $200-225 range, but who knows what kind of bag of parts you'll be getting.
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Well, here is the beauty of going through Scott Harms for your carb.

He does really nice work
It WORKS!
I’m sure he has some spare parts.

IF you decide to get a TQ for experimentation, talk to Scott directly and just ask for an early big primary model. Not the first year of the carb.
The larger primary carb works best on modified 340’s and up.

Cut the cheaper AFB rods down 3/4 of an inch and re bend to fit the TQ. Be accurate at the bend point. Grab the secondary tuning tool. It just makes life a lot easier to tune the secondary opening point with the tool. Do not cap the bowl vent on the top part of the carb.

Do not get frustrated. It’s a tricky carb until you get to know it a little and then you realize, it ain’t that tricky. It has settings that need to be measured and adjusted. Real close is good enough for most settings.

If you want to give one a shot and rebuild it yourself, you may need to bush the throttle shafts. That can be a pain. Otherwise, there not a hard carb to rebuild at all.

Just have fun and tinker with it.
 
Montclaire said:
I'm in the same boat. Lately I've been very tempted to dig into one though. Harms wants $400 to restore one, which is more than I'd like to spend but probably worth it. There are also several sources for remans in the $200-225 range, but who knows what kind of bag of parts you'll be getting.
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theres members here that rebuild them, problem is finding the right ones in good nuff shape to rebuild!!
 
I have a 9077s on the shelf which should be large primary. I've robbed a couple parts off of it over the years but it's mostly complete. It probably only saw 15 years of road use, I got it with some other parts along the way. I think the main trouble spot on them is the base plate.
 
Montclaire said:
I have a 9077s on the shelf which should be large primary. I think the main trouble spot on them is the base plate.
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The throttle shafts wear out. Not uncommon on a carb.
The middle section can warp or crack easy if mis handled. Also if the engine overheats badly or very high temp repeatedly. Also the little fuel tubs that are factory glued on can come loose. JB weld has fixed that for me.
The tops are generally rock solid. Rust and or corrosion can inhibit free movement. Also bent rods from being hand handled badly.

If you dismantle the carb in full, have some very fine sand paper on a roll or stick, what ever,,,, and smooth out the smallest areas where a shaft may turn or other parts contact each other.

Once again, throttle shafts are a PIA. If you can find a suitable bushing to fit snugly over the shaft, then a drill to open the shaft tunnel up to a size for the bushing to be pressed in is the next hurdle.

If the kid section is warped, you can try and level it back out with a hard block and course sand paper. If not, TOMCO has middle sections.
 
I found some cheap roller regrinds online. That being said, I don't know if I want to spend the $ to swap a cam and springs. I might just degree what I have and invest in some gears. I want this build to be more pedestrian anyway. A smooth idle with good gears and a screaming TQ sounds ok to me.

Hydraulic Roller Camshaft Mopar LA HR-270-SBMs 318 340 360 Swinger Demon Dart | eBay

Hydraulic Roller Camshaft Mopar LA HR-276-SBMs 318 340 360 Swinger Demon Dart | eBay

Hydraulic Roller Camshaft Mopar LA HR-279-SBMs 318 340 360 Swinger | eBay
 
Montclaire said:
I found some cheap roller regrinds online. That being said, I don't know if I want to spend the $ to swap a cam and springs. I might just degree what I have and invest in some gears. I want this build to be more pedestrian anyway. A smooth idle with good gears and a screaming TQ sounds ok to me.

Hydraulic Roller Camshaft Mopar LA HR-270-SBMs 318 340 360 Swinger Demon Dart | eBay

Hydraulic Roller Camshaft Mopar LA HR-276-SBMs 318 340 360 Swinger Demon Dart | eBay

Hydraulic Roller Camshaft Mopar LA HR-279-SBMs 318 340 360 Swinger | eBay
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be best to send out your factory cam to racer brown in MD and have him regrind it to fit your combo, and your intended use! by time you figure shipping and fleabay fee's probably be cheaper to!
 
and if you want 8 degrees less seat duration and a better profile for the same lift give MIke jones a shout about is inverse radius profiles
would keep that torque up
whatever- do get something to fit your combo
and
less is more
 
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