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360 Max Rpm


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39 replies to this topic

#1 nicolae788

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Posted April 17, 2005 at 11:11 am

Hello!

I wonder what's the max. RPM that a 360 cast crank would take. Would it take 6000 RPM's ?
The engine that i am asking for it's a 1978 - 1979 LA 360 with a 2 bbl Holley. The future carb will be a Rochester Q.

Thank you very much and the best to all.

Alex.

#2 cavemanmoron

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Posted April 17, 2005 at 12:28 pm

if you want higher rpm,you need to install a bigger cam,and Valve srpings.

Dual exhaust is smart too.

79 2 bbl rated 150hp [at]3600
79 360 4bbl was rated 170 hp [at]4000 rpm,in Calif. emmisions.

360 hp 4bbl in Volare/Aspen was 195 [at]4,000 rpm,If I recall
that had a slightly hotter cam,and dual exhaust.

Why the 6,000 rpm hopes?

what gear do you have?
what car do you want to use the engine in?

#3 TWX

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Posted April 17, 2005 at 01:04 pm

I've pushed the 360 in the '78 Cordoba up just past 5500 a couple of times while flooring it to pass, but it really didn't like it. The engine is stock though, so the only real advantage that I had was the dual exhaust with headers.

#4 Gibons

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Posted April 17, 2005 at 03:19 pm

I think your asking if the crank will take 6000 rpm? If thats your question it'll take it no problem I've heard they can take 6500 rpm and last. But your valve springs won't lol nor will your cam, or intake etc.

Edited by Gibons, April 17, 2005 at 03:22 pm.


#5 MrBelvedere (converted)

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Posted April 18, 2005 at 09:51 am

the 360 stock cast crank will live into the 7500 rpm range for short burst ie. drag racing in the 1/4 or 1/8 mile as for continuios duty like constant high rpms ie nascar i dont know the 70 duster i used to be head crewchief on we ran a stock cast crank in our 360 spun it to 7500 and shifted it ran it through the traps at 7800 rpms and ran the engine 3 yrs before we pulled it and freshend it up and you know what we found cracked and or broken nothing we even had the crank x-rayed it was good to go so with fresh bearings and rings it went 2 more yrs theb we put a 408 in her then 360 we were running was 13to1 compression

#6 TWX

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Posted April 18, 2005 at 01:10 pm

Yeah, everything that I've read about the 360 indicates that they did something very much right with that crank shaft, and that it'll take much more abuse than one would expect.

#7 MrBelvedere (converted)

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Posted April 18, 2005 at 10:51 pm

dam skippy it will lol

#8 nicolae788

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Posted April 20, 2005 at 01:32 pm

Thank you for your reply.

I am going to make some mods on this engine with all that it takes like the camshaft and valve springs. My questionm indeed was if the crank can support 6000 RPM because i do not have enough cash to buy a steel one.
I will order parts from a company called Campbell Performance parts. Do you know about it?
They have a lot of peformance parts for Mopars and i already talked with them and they seem to be quite nice. :)

I do not know about the intake but i will try to use the stock intake first and then after i will harvest more money i will buy a perf one.
Anyway i can't wait till it will be ready.

#9 nicolae788

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Posted April 20, 2005 at 01:35 pm

And about the gear: i have a 2.70 or something in this area( i do not recall right now) and the engine i want to use it in a Chrysler new yorker.
It will be a nice car that's already fast but faster with the refreshed V8

#10 Gibons

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Posted April 20, 2005 at 01:56 pm

A stock 4 barrel intake is a good intake it will breath past 6000rpm not as some aftermarket single planes but you'll keep some low end torgue. Which you'll want for 2.7x gears. You must be going fairly rank on the cam for a street driver if your planning on running it to 6000rpm.

#11 nicolae788

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Posted April 20, 2005 at 05:33 pm

This is a good thing that the stock intake will perform so good. My cam will be as folowing:

268/276dur-429/444lift idle to 5800 rpm

I think this a good setup regarding the cam and will provide me with a streetable engine.
I m also going to change pistons at the next oversize and rings. I will make a much as i can :).
Any sugestions are welcome.

Thank you!

#12 Gibons

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Posted April 20, 2005 at 09:27 pm

whats its duration at .50 and thats not real high lift.

#13 MrBelvedere (converted)

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Posted April 20, 2005 at 10:08 pm

nicloae call comp cams and get an extreme energy cam shaft ok trust me you will way more pleased with it then you will the one you have listed as for slugls get a set of keith black pistons p#kb107 those are very reasonably priced and a quality peice also use a double roller timing chain a good melling oil pump and a performer rpm intake as for carburation use a holley 650 double pumper and for the transmission 2500 stall and a good shift kit and 355 gear out back with a sure grip all of this stuff will make you a very potent street car and extremly user freindly

#14 Gibons

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Posted April 21, 2005 at 12:36 am

ya I'd like to try a XE cam for my next build. I've got a comp cam in right now and I'm pleased with it. For a 318 its got lots of snap.

#15 seagull03

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Posted April 21, 2005 at 06:55 am

whats its duration at .50 and thats not real high lift.

<{POST_SNAPBACK}>


If I'm not mistaken, that's the stock 340 cam or pretty close to it.
I've vague intentions of doing same with my own 360 some time.
Not a race machine but nice. It's good to know about the crank.

#16 Gibons

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Posted April 21, 2005 at 10:51 am

The cam in my 318 right now is a comp cams 260h. 212 degrees at .50 and .440 lift on both sides. I've been told its actually a better cam than the old stock 340 cam. Just because of better technology etc. I read a few dyno sheets were they dropped on in a 318 stock no rebuild with a cast iron four barrel and made over 260 horse out of a 318. Thats getting pretty darn close to a 340 for horsepower. And thats with garbage for heads and exhaust manifolds put 340 manifolds and some ported heads on and your up to 300 some horse. lol sorry I'm babbling anyway the point I'm trying to make is thats a pretty mild cam for a 360 because of the cubic inch differance. Something like comp cams XE268 cam would be more like it I think its duration at .50 is around 230 and lift is about .480. Theres a little less on the intake but I don't have the book right here. I also read and article they put a XE262 cam in a stock 360 four barrel then dropped hooker headers on it and got 335 hp and 390 foot pounds of torque.

#17 seagull03

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Posted April 21, 2005 at 12:28 pm

I think we're mostly agreed that 275 hp was a lowball figure for the 340. In one build-up article I read, they got 281 hp out of a 340 rebuilt to 1970 factory spec but with carb problems (too lean wide-open). Just slapping on an un-tuned 800 cfm qjet got it up to 315. Headers made it 330. A "modern" intake brought it to 355. Still stock otherwise. I wish I could find that article again. It made very interesting reading.

Anyway.

That last 360 setup you mentioned (with the XE262) looks to be in HP 383 territory. It would be very nice in an A body. How is it for day-to-day driveability?

#18 Rodger

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Posted April 21, 2005 at 12:47 pm

Hola

At our local pick & pull a MoPar OEM four bbl intake manifold from any MoPar is $10 dollars. If you peak around the vans of the same era you will find about half of the 360 powered 4 bbl ones with dual snorkel air cleaners. If you do this take a note on the lenght of the snorkel to flex tube adapter since they made more than one style.

Do some selected shopping and you can have more horse power that appears as if MoPar had made your EC5 coded 245 hp 360.

Instead of ruining the under-hood appearence and having the cost and problems of after market tube headers have the local muffler shop ( non national chain shop ) make the exhaust tubing the same inside diametor as the inside of the exhaust manifold and not to vary on this inside size to the rear bumper. If you do this, the hp number has just moved upward.

If the muffler shop puts in an "H" style cross over pipe before the dual mufflers it will aid in the horse power numbers. If they follow your wish and install an "X" before the mufflers you will get more power and better emmissions too, with a lower more refined audio.

If you have the OEM styled dual snorkel intake, the tube size the same as the exhaust manifold, the "X" and any muffler that is worth its weight you are now way above the EC5 coded engine. If you use MoPar cam # P4452782 which is the 340 resto cam ( that many copy ) the 360 will idle as if its on the dealers show room floor and run better than any pizzia delivery driver's car.

The 340 was under-rated at 290 hp without fresh air induction or "X" pipes, so what would your 360 be under-rated at ??? Better than a late modle OEM EC5 engine ???

Rodger & Gabby
Colo Spgs

#19 Gibons

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Posted April 21, 2005 at 04:33 pm

Oh I believe the 340 is a good engine just saying that the cam they used is no longer up to the modern cams. You have to remember to that the 340 had over 10 to 1 compression were the 318s I read about had 8 to 1 if they were lucky. Also had factory free flow manifolds were the 318 that they tested had logs. 340 also had bigger valves and runners and 22 cubic inches more. Also the 340 was rated gross horsepower at 275. That means it didn't have water pump, alternator, power stearing pump or fan on it when it was dyno'd. Which is probably good for a 50 or so hp loss over the net( rated with all those things on it) 245 hp 360. I don't doubt that many of the 340's were higher than that 275 horse perhaps some stock one's may have even hit 300+ when ones specs came together. But drop a new comp cam in them and you'll probably gain another 20+ horse power as long as you go for similar duration and lift. And I believe the XE 262 cam in that 360 was very driveable. Same cam in a 318 you'd have a lumpy idle but in a 360 I'd think it would be good.

Edited by Gibons, April 21, 2005 at 04:35 pm.


#20 cavemanmoron

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Posted April 21, 2005 at 04:55 pm

Oh I believe the 340 is a good engine just saying that the cam they used is no longer up to the modern cams. You have to remember to that the 340 had over 10 to 1 compression were the 318s I read about had 8 to 1 if they were lucky. Also had factory free flow manifolds were the 318 that they tested had logs. 340 also had bigger valves and runners and 22 cubic inches more. Also the 340 was rated gross horsepower at 275. That means it didn't have water pump, alternator, power stearing pump or fan on it when it was dyno'd. Which is probably good for a 50 or so hp loss over the net( rated with all those things on it) 245 hp 360. I don't doubt that many of the 340's were higher than that 275 horse perhaps some stock one's may have even hit 300+ when ones specs came together. But drop a new comp cam in them and you'll probably gain another 20+ horse power as long as you go for similar duration and lift. And I believe the XE 262 cam in that 360 was very driveable. Same cam in a 318 you'd have a lumpy idle but in a 360 I'd think it would be good.

<{POST_SNAPBACK}>

???
Oops, :( Look at NHRA for how much the 340 was "factored",and you will find it is more than 300 horsepower.
Edit, I either remembered wrong,OR NHRA changed the "factor".
The 340 in a 68 Dart is listed at 299HP for "stock" class.

A 318 for "stock" class is derated to 195hp,{factory rated 230hp}
but the 1968 Dart 273 mopar claimed 190hp,and that is the NHRA stock rating.
Odd.a 66Dart 273,2bbl is derated from 180 claimed to 165hp!

When I rebuilt my 318 i used Mopar Performance cam
# 4452759, valve spring # 4286813
.430/.450 lift, I am happy with it.

http://store.summitr...k=KeywordSearch

Edited by cavemanmoron, April 21, 2005 at 06:29 pm.



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