340 and 318 question

[Snug]

I have a stock 318 that needs rebuilt, also a 904 tranny. I have a chance to buy a 68 340 with 727 that needs rebuilt. Would I be better off in the long run to spend the money on the 340, or just rebuild the 318 with some heads/headers?

Thanks
Doug

[djswwg]

the 340/727 is the way to go. stronger, faster,more fun, and about the same expense to rebuild as the 318/904 combo......djs

[Snug]

I figured that would be the answer, but it's always good to have others confirm my own thoughts.

[MOPEkid]

Plus, the 340 will be more valuable. I'm sure if you kept it in good condition and treated it well you could sell it again for a decent amount of cash.

[owatajrkiam]

The 318 can still perform with just a few bolt on mods,...cam,induction,headers or hi-po manifolds all favour this engine!. The limiting factor is the smallish heads! you could step up to a "J" head or simmilar w/ the 1.88 valve or go to a magnum head! This is the approach when i took a 340 block w/4" stroker crank and Diamond +.040 forgings (418")w/Eddy Magnum heads!. The cast iron magnum heads will wake up any LA small block. Early 318's had steel cranks,get some good Scat or Eagle rods and hyper or forged pistons to boost the compression a bit and some oiling mods,and you've got a stout bottom end!. Add the Magnum cast heads with a bit of porting,and a good cam and 400 hp is a possibility!.Good 340 blocks are becoming harder to find. BUT,the 340 setup as stated above is the way to go if you plan on getting serious! By the way,this is my first posting and i'm happy to be here and get more info,and to help others!

Glen

[340dailydriver]

I'd go the 340 combo but remember if you are running todays pump gas you'll need hardened valve seats for the unleaded gas. You could go either way but most will say your money will be better spent and its easier to get power from the 340.

[3404spdvaliant]

67' was the only year that you MIGHT find a steel crank in a 318 and would probably have been in a truck.It would have been a 273 left over.
Run the 340 w/ built 904. It has better gearing and takes less HP.
904 came factory behind 360,and today is used in drag racing from 225-440 w/adaption.

[djswwg]

how much power/tork will a 904 take? how heavy are the vehicles you have them in? I like the better gearing but how durable are they under big loads?.....djs

[rumblefish360]

Snug; Since I'm spending your money, LOL I would do the 340/904 for an all around great performer. The 727 is rated at about a tenth slower than a equal built 904. But since your not raceing........
You may want to go for a heavier duty tranny, the 727.


djswwg; When buit right, they'll take what ever you throw at them shy of what ever the mind can dish out. I just have not realized if there in pro stock or not.
The quickest I have seen one run was 9.90 flat.

owatajrkiam; Welcome aboard Glen. I think you'll find mildly ported 318 heads better than a set of bolted on 360/1.88 valved heads. Been there done that. Though I can see the cheaper route of 360 heads being done more often than a mild porting of the 318 head. It's just the big port flows the charge at a slow rate making it lazy and not so atomized over a high velocity 318 head.

The Magnum head is a great HI performer for the 318. I think it splits the gap well.

[abodyjoe]

if were me between the choices you listed.. i would go 340 and use the 904

[rumblefish360]

Hey Joe. Glad to see you here. Welcome aboard.

Eveybody, this is Joe, he knows a bit about Mopars and A bodies. He gets my vote and backing!

[abodyjoe]

lol.. thanks man. heard about this place and finally checked it out.. looks like a cool place.. just gotta learn my way around.

[340dailydriver]

Jersey has always been good Mopar country...at least till they rot away.

[Snug]

Can't believe all the replies. Thanks for the suggestions. I will look into the 340/904 combo. This is a great site.

Doug

[valiant64]

If you're gonna run the 904, a bone-stock build will probably not last as long as the 727. Since you're not racing your car, the tenth of a second faster with the 904 is of no real benefit to you. It is true that the gear selection for the 904 is better, but even a stock 727 will outlive the 904 behind a 340. Thats why Chrysler never offered the engine with the 904.

[abodyjoe]

Originally Posted by valiant64

If you're gonna run the 904, a bone-stock build will probably not last as long as the 727. Since you're not racing your car, the tenth of a second faster with the 904 is of no real benefit to you. It is true that the gear selection for the 904 is better, but even a stock 727 will outlive the 904 behind a 340. Thats why Chrysler never offered the engine with the 904.

a 904 rebuilt by someone that knows what they are doing and quality parts and maybe a lil shift improver kit will hold up very well behind a 340... that 727 over a 904 is just an old school way of thinking...

[dodger1]

If you feel you want to rebuild either trans, I'd go with the 904 and save some lbs. Either one will do the job for you, but there's a lot of experienced shops out there now that have worked on the 904/998/999/A500 family. I'll agree with abodyjoe.

[vinnys63valiant]

340 the way to go. i have a 318 i got from a fellow mopar man thats been bored and has a stroker crank. but he spent the money to get it there.id definantley do the 340 if i was you.