Codybones
Member
I have a 72 Dart with a 318 should I swap to a 340 when a swap the 3 speed on the tree to a 4 speed on the floor?
318 swap
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Why? You can economically "soup" it up without pulling the engine. Is there anything wrong with the 318?
yes. from the info you posted, yes.
Codybones
Member
No real goal I’ve just always heard the 318 was a dog, that being said I’m not that concerned with tons of power just a nice runner.
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i dont know much about the 318 I would probably rather pull it and rebuild it and through it back in
Dan the man
Well-Known Member
For your goal, the 318 will be fine. Read anything that you can find on what 318willrun has done with the 318.
Cubic inches are always better for performance but the 318 is a good engine to build some decent power. Pretty easy to get 1 HP per CI out of any V8 these days.
A performance 318 just never was offered by the factory, one of the main differences between 318 and 340 is bore size 3.91" vs 4.04" other than piston a 318 can use all the same parts as a 340. A 318 will respond like most engines to a basic hop up, mild cam, 4 bbl, cr, exhaust.
340 are hard to find and are expensive the choice is generally between a 318 vs 360 most will say go 360. Either will work especially for mild performance.
I've seen 318's people swore were 340's. I've seen 340's that ran like tired 318's. Basically, they are about the same block except the 340 has bigger bore (which matters) and cost bigger money to buy. 340's only made from '68-73, and then at limited quantities. 318's propelled "Eric the Red's" ship and your local street sweeper.
318's were the work horses. They just did not get the high performance goodies. Big port heads were found on 340's or any 360, 4 barrel intake and carb, performance cam and valve springs, double roller timing chain, quick curve distributor, good exhaust, and to make it live a high pressure oil pressure spring and a windage tray. It's pretty simple really, they will all just bolt onto a 318. As for bore size, a 340 has only .13 inches larger diameter and a 360 is only .09 bigger diameter. All things being the same, you'd be hard pressed to tell the difference between any of them.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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If you have to ask, then yes. Better is a 360; then you can keep the 3-speed, or put an A833overdrive in it.
Unconventional
Well-Known Member
I like the way a 4"x3 1/4" motor runs and 318s and 340s don't miss that by much. Got to get the air and fuel to it and out of it in the proper fashion.
Do you have a 340 running and ready to drop in?
Is the 318 in good condition?
318 are given the “Dog” moniker because they were often low compression engine (7.8-1) saddled with a lot of emissions devices and low gear ratios, 2bbl carbs and hwy gears. Early 70’s and ‘60’s 328 had a little more compression and work well with small camshafts.
They are very good in obtaining mileage if not given to much cam and gear. AJ/fromS suggested an OD trans which is difficult to come by. But super helpful for mileage concerns. His suggestion of a 360 and I’ll add it in a 5.9 for more power over a 340 is a wise choice since a good running 5.9 will make 300hp with just an intake and headers. You’ll just need to address the balance issue with a proper flywheel or weight on the flywheel.
FWIW, my 5.9 gets only 17 move but it is in a bigger car, a ‘1979 B body Dodge Magnum w/3.55 gears.
If you want to hop up the 318 AND you’re doing a rebuild on it, the only expensive part that differs from the larger engine that is expensive are pistons. So if you go out and get a 340 block, that cost in getting the 340 block alone will be more expensive that the 318 pistons.
Is the 318 in good condition?
318 are given the “Dog” moniker because they were often low compression engine (7.8-1) saddled with a lot of emissions devices and low gear ratios, 2bbl carbs and hwy gears. Early 70’s and ‘60’s 328 had a little more compression and work well with small camshafts.
They are very good in obtaining mileage if not given to much cam and gear. AJ/fromS suggested an OD trans which is difficult to come by. But super helpful for mileage concerns. His suggestion of a 360 and I’ll add it in a 5.9 for more power over a 340 is a wise choice since a good running 5.9 will make 300hp with just an intake and headers. You’ll just need to address the balance issue with a proper flywheel or weight on the flywheel.
FWIW, my 5.9 gets only 17 move but it is in a bigger car, a ‘1979 B body Dodge Magnum w/3.55 gears.
If you want to hop up the 318 AND you’re doing a rebuild on it, the only expensive part that differs from the larger engine that is expensive are pistons. So if you go out and get a 340 block, that cost in getting the 340 block alone will be more expensive that the 318 pistons.
Just buy a Chevy. None of the Chevy guys ever talk about their engines being dogs.
Man, hes only got 14 posts, he might take you seriously!
You can stroke your 318 to 390. There are kits for that. How crazy do you want to get? There are top end kits for your 318 that are awesome. But all that is only part of the package. Start building the motor and the trans goes. Fix that and the rear end isn't far behind. Get all that sorted and then the suspension needs to be addressed. The best plan is to have a plan and stick to it. There will always be some one faster, so pick a level you will be happy with.
That ain't no Chevy guy.
NOTHING Wrong with a 318. I will say I have had 360s (the SBM that most around here "hail" and "worship" around these parts) that definitely were dogs, too.
Either can be woken up with standard hot rodding techniques.
Either can be woken up with standard hot rodding techniques.
The biggest problem I've ever had with a 340 is I've never been able to get my hands on one. theyre made of unobtanium"
and strangely, thru all the years the 318 was "advertised" as having higher CR than 360s ever had even if only by a couple of points. But the truth is if you ever measure out and "blueprint" one they almost always fall short of "advertised" because of "tolerance stacking" some worse than others. If you rebuild one and do the work to bring it up to "advertised" rating or slightly above, even with stock cam and keep the 2 bbl even, that in itself will be an improvement over dead stock as it came.... and being "fresh" on top of it will be an improvement over "as originally built" but you can definitely do even better than THAT. Keep the 318/ it will do everything you need it to and then some.
Codybones
Member
thank you, I’m starting to think that’s the way to go, lots of very good input from the forum
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