273 cam suggestions

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CUDAGUY

aka Prince Valiant
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heres what the rest of the package will consist of, looking for suggestions for a very hot cam for the 273 in my Valiant wagon

original 273 shortblock (compression test shows 120psi accross the board)
late 80's #302 swirl port heads...cleaned up but unported...stock valves
stock replacement 340 valve springs
performer intake
holley 600cfm vacuum secondary carb
recurved distributor/mopar orange box....maybe GM HEI
not sure about what to do with the manifolds...probly using stock early-A's
904 auto
3.23 gears


I have a mopar '759' cam in my 318 and it will soon be riding the shelf...heres the specs....

http://www.summitracing.com/parts/DCC-4452759/

too big for a 9:1 or so 273? I have all the valvetrain to go with it as well
 
I run the Comp cams 20-246-4, 468 lift. solid recommended upgrade for the 10.5:1 commando motor. Motor screams.
 
Isky E-4 solid has been around for years. I think at least one member is running such. Might be worth a look.

At some point you'll have to reconcile the "very hot cam" and 3.23 gears. The 284/.528 solid MP cam will certainly give you a rough idle, and that "coming up on the cam" feeling, especially in a little 273, but not much torque below 3000 RPM. Less cam would probably make for a quicker car that's a whole lot more pleasant to drive in traffic.

The cam you are thinking of is actually milder than a factory 340 cam, but a pretty reasonable choice. A Comp XE262 would be similar. Neither cam would be "very hot" by any stretch. Also, if you are thinking of stock 273 exhaust manifolds, there is little point in going much wilder with the cam. You won't make any more power, you'll just give up low end.

Why on earth would you downgrade to GM HEI?!?
 
Isky E-4 solid has been around for years. I think at least one member is running such. Might be worth a look.

At some point you'll have to reconcile the "very hot cam" and 3.23 gears. The 284/.528 solid MP cam will certainly give you a rough idle, and that "coming up on the cam" feeling, especially in a little 273, but not much torque below 3000 RPM. Less cam would probably make for a quicker car that's a whole lot more pleasant to drive in traffic.

The cam you are thinking of is actually milder than a factory 340 cam, but a pretty reasonable choice. A Comp XE262 would be similar. Neither cam would be "very hot" by any stretch. Also, if you are thinking of stock 273 exhaust manifolds, there is little point in going much wilder with the cam. You won't make any more power, you'll just give up low end.

Why on earth would you downgrade to GM HEI?!?


the '759' cam is really choppy in the 318 that its in now...way more than the 340 cam was. Its pretty worthless under 2k but pulls hard to 7k. the manifolds probly wont stay, I will most likely atleast upgrade to 340 or magnum manifolds.

GM HEI is an upgrade in my opinion, no ballast resistor, no 'box' to melt goo all over the place, 14-volts to the coil....and always able to find an HEI unit if it does go bad unlike the mopar stuff
 
If you are looking hydraulic, I think an isky 264 megacam would be cool in that engine.
 
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Crane Cams 690141 - Crane Racing Camshafts

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  • Camshaft, Hydraulic Flat Tappet, Advertised Duration 294/294, Lift .480/.480, Mopar, Small Block, Each
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Brand
Crane CamsManufacturer's Part Number
690141Part Type
CamshaftsProduct Line
Crane Racing CamshaftsSummit Racing Part Number
CRN-690141UPC
021174047493

Cam Style
Hydraulic flat tappetBasic Operating RPM Range
2,800-6,000Intake Duration at 050 inch Lift
222Exhaust Duration at 050 inch Lift
222Duration at 050 inch Lift
222 int./222 exh.Advertised Intake Duration
294Advertised Exhaust Duration
294Advertised Duration
294 int./294 exh.Intake Valve Lift with Factory Rocker Arm Ratio
0.480 in.Exhaust Valve Lift with Factory Rocker Arm Ratio
0.480 in.Valve Lift with Factory Rocker Arm Ratio
0.480 int./0.480 exh.Lobe Separation (degrees)
106Computer-Controlled Compatible
NoGrind Number
H-222/3200-6Valve Springs Required
YesQuantity
Sold individually.
These racing camshafts from Crane are designed to provide the torque and power you need in the high rpm ranges. These cams are available for a variety of applications in mechanical, hydraulic roller, and flat tappet styles to suit your needs.
Warranty
 
The Isky E-4 is about the closest you can get to the factory HP 273 specs. I used that cam and it runs good. The Schneider cam is rougher idle but produces it's horsepower at a higher rpm. So if you want a lumpy idle, use the Schneider. If you want like OEM use the Isky. toolmanmike (Sorry for the sub par video)

[ame="http://www.youtube.com/watch?v=v555B5_uBJ4"]YouTube - HP273- Isky E4- Accurate LTD exhaust[/ame]
 
The one question that hasn't been asked is what are going to do with the car? Drag race, autocross, street?? Sounds to me it's more of a street car with 3.23's. Having a lumpy cam for the sake of bragging rights is not worth the effort of having a big cam in a small displacement motor driven on the street. E4 is the way I went in my 64 vert.
 
The one question that hasn't been asked is what are going to do with the car? Drag race, autocross, street?? Sounds to me it's more of a street car with 3.23's. Having a lumpy cam for the sake of bragging rights is not worth the effort of having a big cam in a small displacement motor driven on the street. E4 is the way I went in my 64 vert.

street/strip car...any street action is usually from a roll and most likely drag action will be on street tires.

as far as upgrading to commando stuff...its later on down the road, the pistons are the killers and the cam I can get cheap locally, but Im after more off a 'hot rod' type vehicle since Im lacking one.

Im not really after a HUGE cam just something pretty edgy for that small of a motor
 
After reading everything you wrote below, I think the cam listed would do fine with the 3.23 and stock stall converter and tire size. The best mix of exhaust manifolds would be 1 340 exhaust manifold and 1 early Magnum exhaust manifold. You'll have to stand by for the part number IF I can find it, but it comes from the first few years of the Magnum exhaust manifolds mostly found in Dakota's and Ram's. The outlet size is the biggest @ 2-1/4 inch.

I wouldn't go to much larger for a cam myself with the running gear you have now.

Port the 302 heads? OR go to Magnum heads? Often a catch 22 since porting the head is going to be more expensive than getting new Magnum heads, but the rest of the conversion parts needed will just about balance an out to equal price tag.

The only big bennifit in the Magnum head use is the 1.6 ratio and the better ports as cast or ported over the "LA" head, but that's more money over the intail conversion. Catch 22 again.

Your call.

heres what the rest of the package will consist of, looking for suggestions for a very hot cam for the 273 in my Valiant wagon

original 273 shortblock (compression test shows 120psi accross the board)
late 80's #302 swirl port heads...cleaned up but unported...stock valves
stock replacement 340 valve springs
performer intake
holley 600cfm vacuum secondary carb
recurved distributor/mopar orange box....maybe GM HEI
not sure about what to do with the manifolds...probly using stock early-A's
904 auto
3.23 gears


I have a mopar '759' cam in my 318 and it will soon be riding the shelf...heres the specs....

http://www.summitracing.com/parts/DCC-4452759/

too big for a 9:1 or so 273? I have all the valvetrain to go with it as well

the '759' cam is really choppy in the 318 that its in now...way more than the 340 cam was. Its pretty worthless under 2k but pulls hard to 7k. the manifolds probly wont stay, I will most likely atleast upgrade to 340 or magnum manifolds.

GM HEI is an upgrade in my opinion, no ballast resistor, no 'box' to melt goo all over the place, 14-volts to the coil....and always able to find an HEI unit if it does go bad unlike the mopar stuff

Id love to just upgrade to commando specs! $$$$$:tongue9:

street/strip car...any street action is usually from a roll and most likely drag action will be on street tires.

as far as upgrading to commando stuff...its later on down the road, the pistons are the killers and the cam I can get cheap locally, but Im after more off a 'hot rod' type vehicle since Im lacking one.

Im not really after a HUGE cam just something pretty edgy for that small of a motor
 
Commando cam specs from the 1966 version (think 65 & 67 are the same).
Lift .425, Duration 248º, Overlap 46º (Intake and Exhaust are the same.)
Commando specs were 256 degrees duration intake and exhaust, and .420 inch lift on intake and .430 inch lift on exhaust. Taken from T.U.T. #35, "Mopar Stock Eliminator Packges" in the Direct Connection Performance Book. The stock cars with 4 speed cars were quick. They usually came with 3.23's in the rear. I've run up to 284 duration mechanicals in the 273 but the best was the stock 340 cam on the street. Soooo I'd recommend something around 256 to 270 duration. Don't forget a double roller timing chain. Does the HEI distributer fit in an early A? They are severely RPM limited in stock form, about 4,500 without mods, if I remember correctly. I have friends who own Chevys. I always ran the Mopar Performance kit.
 
Call these people. Tell them what you want to do and they will custom grind for less than a lot of the out of the box units out there.
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273, 8.5:1, stealth, isky e4, 3.23's, 302 heads, great combo. Even better 4 degrees advanced cam. Very similar to your setup
The cam you picked looks good too, other than losing the solids
 
After reading everything you wrote below, I think the cam listed would do fine with the 3.23 and stock stall converter and tire size. The best mix of exhaust manifolds would be 1 340 exhaust manifold and 1 early Magnum exhaust manifold. You'll have to stand by for the part number IF I can find it, but it comes from the first few years of the Magnum exhaust manifolds mostly found in Dakota's and Ram's. The outlet size is the biggest @ 2-1/4 inch.

I wouldn't go to much larger for a cam myself with the running gear you have now.

Port the 302 heads? OR go to Magnum heads? Often a catch 22 since porting the head is going to be more expensive than getting new Magnum heads, but the rest of the conversion parts needed will just about balance an out to equal price tag.

The only big bennifit in the Magnum head use is the 1.6 ratio and the better ports as cast or ported over the "LA" head, but that's more money over the intail conversion. Catch 22 again.

Your call.

Magnum heads are what is getting used on the 318 that will eventually find its way into this car. but the added expense of the right manifold over the one Ive got, the right pushrods for oiling...somewhat of a tight budget on this motor for now...porting the #302's isint that difficult, I have a pair on the above mentioned 318. The car that the 318 and cam is in has 3.23's and 2500 stall and worked well on the street (avg. 15mpg) and roasted tires to a 14.6@97 ....Im just curious how radical the '759' cam will be with 45 less cubes, it is 'healthy' in the 318....I will try to get a vid later.

Does the HEI distributer fit in an early A? They are severely RPM limited in stock form, about 4,500 without mods, if I remember correctly. I have friends who own Chevys. I always ran the Mopar Performance kit.

you dont use the whole dizzy, just the 4-prong control unit in place of the mopar box

273, 8.5:1, stealth, isky e4, 3.23's, 302 heads, great combo. Even better 4 degrees advanced cam. Very similar to your setup
The cam you picked looks good too, other than losing the solids

should still run on regular...I dont mind losing the solids in a car that will be driven often...less time tinkering, more time driving:toothy8:
 
use your intenals and stock solid rocker gear ("scollop rockers for lift weld redrill oil port " can tell you when youre older...) , double spring it as it will rev, molly -100' retainers, same push rods are ok, take it your 302 heads nice short curve/bowl port?
you say 8.5 compression so give some cam ideas, -streetable '107'-108 lobe sep. advance cam at least +4 to 6 degrees or more (as low comp, it will still rev")

get close but dont go over .498' lift unless you want to spend xtra $$$$ on a hole new valve geometry,
go for fast ramp on lift being solid, 50' duration intake 233 ex 239 your advertised go for 290 or less,
as for 904 get some one good with Tconvertors cut up a pulsar/skyline 3000rpm stall and put a full manual reverse valve body kit throuhg it,
all this and good maifold/carb will contort the wagon a bit... discs definately a luxury,

I', running 63 AP5 318 12.6 1/4mile, 318 head, 273 solids+internals, low compression 8.7 :cry:,.. 105 lobe sep :tonqe: (lumpy), 50'@242-249 under 288 advertise, +8 advance, 55 ad on ignition timing, runns on 91 otane, 3200stall 3.7 spool... small tyres hitting top track speed to quick @ 7000rpm+ (3.45 diff in work). very tourquey, street friendly , but very voilent accelertion for an old girl...

if you want even hotter for d 273 wagon go smaller lobe sep(106) advance cam +9 degrees, look at piston to valve clearance!!! as we do! with hotcam, quick ramps, if you havent put big valves in yet don't, change gear ratios, and get on to smokey uniquek? (cowboy that writes **** bout mods n carbs) you will have to mod d square bore carb a bit,

other than that one smokin safari adveture,

Chairs,
Hune
 
I do not have it running yet so I have no comment on how it works. I have stock heads with 1.88 intake valve, mild portwork and egge 10.5 pistons ($$) using thin mopar headgaskets .028.

Comp Cam 20-233-4

Here is the specs for the solid cam I picked out for my 273 Commando:

COMP Cams Xtreme Energy Camshafts
Summit Racing Part Number CCA-20-233-4
UPC 036584079996

Cam Style Mechanical flat tappet
Basic Operating RPM Range 2,000-6,000
Intake Duration at 050 inch Lift 230
Exhaust Duration at 050 inch Lift 236
Duration at 050 inch Lift 230 int./236 exh.
Advertised Intake Duration 268
Advertised Exhaust Duration 274
Advertised Duration 268 int./274 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.501 in.
Valve Lift with Factory Rocker Arm Ratio 0.488 int./0.501 exh.
Lobe Separation (degrees) 110
Intake Valve Lash 0.016 in.
Exhaust Valve Lash 0.018 in.
Computer-Controlled Compatible No
Grind Number CRS XS268S10
Valve Springs Required Yes
 
I do not have it running yet so I have no comment on how it works. I have stock heads with 1.88 intake valve, mild portwork and egge 10.5 pistons ($$) using thin mopar headgaskets .028.

Comp Cam 20-233-4

Here is the specs for the solid cam I picked out for my 273 Commando:

COMP Cams Xtreme Energy Camshafts
Summit Racing Part Number CCA-20-233-4
UPC 036584079996

Cam Style Mechanical flat tappet
Basic Operating RPM Range 2,000-6,000
Intake Duration at 050 inch Lift 230
Exhaust Duration at 050 inch Lift 236
Duration at 050 inch Lift 230 int./236 exh.
Advertised Intake Duration 268
Advertised Exhaust Duration 274
Advertised Duration 268 int./274 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.501 in.
Valve Lift with Factory Rocker Arm Ratio 0.488 int./0.501 exh.
Lobe Separation (degrees) 110
Intake Valve Lash 0.016 in.
Exhaust Valve Lash 0.018 in.
Computer-Controlled Compatible No
Grind Number CRS XS268S10
Valve Springs Required Yes

Shoot a video when you get it running. I'd like to hear that one. toolman
 
I do not have it running yet so I have no comment on how it works. I have stock heads with 1.88 intake valve, mild portwork and egge 10.5 pistons ($$) using thin mopar headgaskets .028.

Comp Cam 20-233-4

Here is the specs for the solid cam I picked out for my 273 Commando:

COMP Cams Xtreme Energy Camshafts
Summit Racing Part Number CCA-20-233-4
UPC 036584079996

Cam Style Mechanical flat tappet
Basic Operating RPM Range 2,000-6,000
Intake Duration at 050 inch Lift 230
Exhaust Duration at 050 inch Lift 236
Duration at 050 inch Lift 230 int./236 exh.
Advertised Intake Duration 268
Advertised Exhaust Duration 274
Advertised Duration 268 int./274 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.501 in.
Valve Lift with Factory Rocker Arm Ratio 0.488 int./0.501 exh.
Lobe Separation (degrees) 110
Intake Valve Lash 0.016 in.
Exhaust Valve Lash 0.018 in.
Computer-Controlled Compatible No
Grind Number CRS XS268S10
Valve Springs Required Yes

if you got a static 10.5:1 comp thats some nice pistons, no matter if you had .038 gasket, advance youre cam up on install at least +4... ("+6 even") being 110 lobe sep on 273 you want to get youre torque band come in pushing A full body, specially if auto' obviously 318-360 are more forgiving (107-108 ls good for drag accel launch), once off the line she will have some sting, good for open street/track race day, and sound like a track car not a harleyLOL (as mine does) and she'll drink 98octane ;)

if using standard valve train (that you should) get d moly -.100'retainers so can fit the spring in without bind and scallop rockers so they dont hit (and reposition oil galley''), you may get away with LT1/chevy brown spring for this too??, unless you are hitting over 7000rpm on reg basis, do doubles!
 
I've run a few different cams in 273s and personally find the Isky E-4 to be the best for a relatively stock engine. Most of the others either lose low end or fail to rev like the 273 should.....
 
I used the Isky E-4 and it works good but it idles pretty smooth but it sounds like you want more. The Schneider cam sounds better and should have a slight lope without loosing too much bottom end. The Comp Extreme Energy cam will be a nasty sounding cam for sure. If you would use that one make sure you have a healthy valve train for high rpm. You also need a 4 speed or a 2500 stall convertor to make it work good. The 302 casting heads won't flow @ too high rpm so too big of a cam will work against them. May be you should contact Hughes http://www.hughesengines.com/Index/index.php and ask for their recommendation. They're the Mopar cam experts. toolmanmike
 
Schneider cam shelf list not suitable for 273,
132F LA (above stock/novice) and 142F LA (if not a class stock cam embarrassing, use what modern day has to offer!)
both are 110 lobe sep, with same lobe duration's for int n ex ,
Then jumps to 284-92F LA great cam 106 LS dual durations @.050 in248/ex258, but ridiculous for 273, and $$$$ to get that .550" lift in...

No company out there really lists an off shelf tear ya plumbs off 273 medium 8.5 to high 11.5 compression cams, anyone considering a cam shaft do some research and request the master grind list from grinders, and most can accommodate lobe sep choice with combined duration choices, one big point is keep your lift under .500" so you can take advantage of the 273 valve train,

seek the master grind list...
quick guide for a mild port 9.0:1 comp 273> 107-108 Lobe Sep,duration @50,lift 228 in with +4 to +10 on ex (depend on head n extractors),advance cam/grind at least +3 to +7,
this is a loose opinion as there is a **** load of variables, obviously cam is one of the if not the last internal component you buy
 
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