350 hp 440 performance
- Thread starter ir3333
- Start date
oldbee
Well-Known Member
Heckuva question, torque should be good ya got the cubes. 375 horse is I-268*x .450”, E-284*x.458”... Hemi is I-284*x.467” & 284*x.473”. Have been wondering lately about trying for a hemi grind for a stock street 440. I always liked a little “something” sound out the exhaust & a stock 440HP just doesn’t sound quite ‘right’ anymore(?)
1967coronet440
Well-Known Member
Hughes whiplash cam or mopar purple cam will give you the sound you’re looking for. Stock 440 is ok for torque, by the time it hits the wheels I’d expect it to be in the 290’s ish somewhere?
oldbee
Well-Known Member
Been looking at “whiplash” ; ‘purples’ are way old school from the 70’s. Jeez has it been that long?
Centerline
Well-Known Member
I have a Whiplash cam in the "stock-ish" 440 in my Polara. Did extensive research before purchasing. The Hughes cam is designed to work with a stock compression ratio engine where others aren't. Haven't fired it yet so I can't claim personal experience with it, but that's coming in the next few weeks.
From a performance standpoint, the Hughes Whiplash cam is not really a race cam. From a sound standpoint however, its music to your ears. There are a few videos on youtube that provide you with a good idea of how this cam sounds so I encourage you to check them out.
From a performance standpoint, the Hughes Whiplash cam is not really a race cam. From a sound standpoint however, its music to your ears. There are a few videos on youtube that provide you with a good idea of how this cam sounds so I encourage you to check them out.
ir3333
Well-Known Member
I was hoping for a frw more first hand accounts of this combination.
The cam i believe is around .256 and.268 duration and the early 350 horsepower 440 had decent compression so part two of this post would be whether detonation is a problem with this engine having such a short duration cam?
The cam i believe is around .256 and.268 duration and the early 350 horsepower 440 had decent compression so part two of this post would be whether detonation is a problem with this engine having such a short duration cam?
lewtot184
Well-Known Member
detonation will be a problem with any 10:1 cast iron head engine; especially if it's open chambered. if you want to try and reduce some cylinder pressure, and this isn't a cure but maybe a help, try a summit 6401 cam. it has a little wider lobe separation, little more duration, and closes the intake valve later than the 256 cam. the 6401 will still let you use power brakes and a stock torque converter.
on another note; a guy I knew used to go to the junk yards and buy 340hp 413's with 268/.430 cam. he kept them stock and they all ran quit well.
on another note; a guy I knew used to go to the junk yards and buy 340hp 413's with 268/.430 cam. he kept them stock and they all ran quit well.
oldbee
Well-Known Member
Well my 440 has the original cam that came out of my 383HP from ‘68. The torque is there right away,, with the above specs I listed && a stock converter with 3.23 gears. The idle is very smooth( almost too smooth, from the way my memory remembers )(?) that’s why I am looking for a little more(?). Plus, if I do a cam change the 8&11yr old grandsons will get to “really immersed” in old engines!
Centerline
Well-Known Member
From Hughes...
"Our Whiplash cam is designed for low, basically stock compression engines. This cam will run on pump gas in a 440 with 9.25:1 or less compression and iron heads. If your compression is higher than this you may need to use a higher octane race fuel. Your vacuum should be in the 9"-11" range using this cam.
(Figures calculated using stock stroke & compression at 750' altitude.)"
If you're running a pre-1970 350 horse 440 with stock heads your compression ratio will be around 10:1 so high test or race gas may be required. In my case, I'm running a +.040 1970 block with flat top pistons that are .92 below deck and a set of 452 heads with 88cc chambers which gives me just over 9.0:1 so I should be good.
"Our Whiplash cam is designed for low, basically stock compression engines. This cam will run on pump gas in a 440 with 9.25:1 or less compression and iron heads. If your compression is higher than this you may need to use a higher octane race fuel. Your vacuum should be in the 9"-11" range using this cam.
(Figures calculated using stock stroke & compression at 750' altitude.)"
If you're running a pre-1970 350 horse 440 with stock heads your compression ratio will be around 10:1 so high test or race gas may be required. In my case, I'm running a +.040 1970 block with flat top pistons that are .92 below deck and a set of 452 heads with 88cc chambers which gives me just over 9.0:1 so I should be good.
oldbee
Well-Known Member
See(?) I’m running flat-tops but have no idea how far down they are(it’s been 30+ since put it together & I “think” I used open chamber heads. My rebuild was after the race engine scattered & I decided to go stock with just a .030” overbore. I need to pull valve covers one of the days to even see what head casting number is,lol.
lewtot184
Well-Known Member
actual ratio will be about 9.5-9.7 with clean pistons and chambers. carbon build up will put this at 10:1+ easily.
the 256 cam closes the intake valve at 58 degrees ABDC. the magnum cam is not a true 268 degrees on the intake lobe; closer to 275. anyhow the service manual says the intake valve closes at 67 degrees ABDC, but it's really 70+. the summit 6401 cam closes the intake valve at 72 degrees ABDC. I think the 256 cam could make too much cylinder pressure for pump gas 10:1 engine that's sealing up good. I wouldn't use any of those tight lobe separation cams with this engine.
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