273 commando cam

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b67cuda

b67cuda

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Hello folks - I am faceing the decision of what cam to use in my 273 commando engine. I am retaining 10 to 1 comp ratio and all the other stock components 4bbl and exhaust it is a 4sd car, I am adding a windage tray and electronic ignition but thats about it. Has anyone out there found success with a certain cam grind or any advise ??
Thanks, Bill
 
good question. I was told once that the stock 340 cam worked great in 273. Dont know if thats best choise today though. I still haven't decided solid or hydrolic for mine. Good luck.
 
Bill,some one had mentioned having used a Isky E4 cam??I'll try to look this up as I'm building a 273 4BBL. motor also. Did you replace the pistons?If so what did you use and what was the price on them?
Ty
 
hi, I've used the Isky E4 on two of my 273 motors. it drops in, no valve to piston issues, can use the stock 273 rockers, etc. it's a short duration cam, on a tight lobe centers. it will work with a stock convertor also. I would change springs though. use a spring with a dampner. the comp 901 or the 942 would work well. the cam will pull 6000 to 6500 RPM. the tight lobe centers and short duration makes for a strong torque curve.
 
Since its a 4spd. car, you could run a good sized cam & not have to worry about a stall. I have the old solid purple 292 cam in my duster & like it. Sounds great at idle & im pleased with the power.
 
Hello. I use a Comp. cams solid unit #20-246 in the 273 commando in my Valiant. Lift is 468 intake & exh. Duration is 224(.050). Wanted to use a solid cam for oldschool sleeper setup and am very pleased. Pulls to about 6000 rpm. Have a stock setup except for the cam,double roller timing chain,edlebrock 600cfm carb. & slightly worked heads. Running a 904 and 3.23 rear. Great low end response. Glad to see 273's being built & not going the crate motor route. Good luck with your build.

Oldschoolcuda
 
Are you looking for a solid or hydaulic cam?


I had a 273 but wasn't running the compression you are going to have. My car is also a 4-speed. I would suggest the old school .474/.474 Mopar Purple shaft. I ran it with a compression around 8.5:1 and it did fair. It was a tad bit over cammed. It does not take much to over cam a 273. Believe I know. But with the 10:1 compression that cam would work really well I believe. I switched out to a Summit cam .441/.441 and that brought the low end torque back up.
 
Another vote for the Isky E-4 here. Works really well with the 10.5 pistons, stock heads etc. I think it works like stock , only a bit more torque.
 
I ran a very nasty 273 for years. The best bet is high lift short duration to keep as much low end torque as you can. They made a 275hp verion in he D dart and it was a racer brown type cam I think and in my old National Service data book it listed a cam with .528 lift. Seat pressure was like 260 .So it had some very still springs and afast flanked solid cam.

I played around with several of the old school mopar grinds, they seem flat on the low end and gradually pulled harder once in the power range for each cam. I think one was like a 280 ish and one was a 292 ish grind. Again both longer on duration and lift was under .500. These were hyd. cams and I was not to happy. So I went back to the Isky I had custom ground. It was a solid lifter design very close to the D Dart 275 HP cam. I ran custom 11.25 pistons .040 over, and with the heads surfaced I was in the 12.0 range. Had to have 100 octane which was very easy to get in the early 70s.

I had both 4 spds and a 727 with manual v body. Ran 4.10s in the 8 3/4. I think I was running a 3900 stall when I went auto 727. My red line was in the 8k range. I had about 7k in the engine and trans and that was in the 70s. Never broken the engine.

Anyway it put out 265 HP to the rear wheels. Bot bad for a 273. Stock it put out 135 with the 2b motor. And the 135 went to about 155 with headers and a 625 AFB on a Holley street dominator that was modifed.

So this is probaly on the high end Bill of what you are looking for. But as mentioned you can over cam real easy a 273. When I had the cam I liked it was not a gradual pull like the hyd mopar gring. It was all or nothing more or less. Once I got in the 4k range it screamed very good. Peak torque was at 5500 with the cam and stayed flat to 6200. Peak HP was at 7800 with my setup. I wasted many a Boss 302 mustang i nthe day. Eveyone thought it was a 340.. nope just a lil ol 273!

well hope that give some insite? Look at the Isky solids cams I think that will fit the ticket for you. Get a grind in the 2500-6000 range for street.
 
titanium said:
Bill,some one had mentioned having used a Isky E4 cam??I'll try to look this up as I'm building a 273 4BBL. motor also. Did you replace the pistons?If so what did you use and what was the price on them?
Ty
Click to expand...


Hey Ty - I was able to use my stock Pistons luckly they were within tolerance - I have another set and a 66 block if you would be interested email me.
Bill
 
Thank you all for the help - I am leaning twords the comp cams BUT I dont know if I should go with the .468 lift or the .495 -- What do you guy think ??
I will be runng 3.55 sure grip, 4sp, trying to stay with stock exhaust?
 
I am building a 66 273/235 motor for my 65 Barracuda and talked with the tech rep at Racer Brown. Discussed in depth the specs of the motor (basically a stock 10.5 motor 4 barrel, stock exhaust manifolds, stock exhaust with muffler and resonator, transmission (4 speed), rear end gears (3.23 SG). Bought a custom ground cam per his recommendation. Bottom line - talk to your cam company and give them as much info as you can.
 
b67cuda said:
Thank you all for the help - I am leaning twords the comp cams BUT I dont know if I should go with the .468 lift or the .495 -- What do you guy think ??
I will be runng 3.55 sure grip, 4sp, trying to stay with stock exhaust?
Click to expand...


One vote for the .468!
 
b67cuda said:
Hey Ty - I was able to use my stock Pistons luckly they were within tolerance - I have another set and a 66 block if you would be interested email me.
Bill
Click to expand...

You can get all the info you need to build just keep trying. I used 1966 Dodge "D" Dart specs and have the entire Dodge information.

I had a 66 Dart 4 speed 8 3/4 put in a 4:89 gear, heavy valve springs, weber pressure plate and hot rod clutch, and some carb work. The car ran GOOD. In the 1/8 mile I was almost unbeatable in the 1/4 I would get passed by big blocks in the last 75 yards. I used M&H slicks, on the street too. Back in the day stop light to stop light in Philadelphia, PA, I dominated! Ran L stock at the track. 273 4 barrel came stock 10.5-1 with solid cam 244* duration and 475 lift. Had to sell it to continue college.

I am building another Dart auto tranny. I am thinking "D" Dart specs? Has not been driven since 1988 and I have it running. Have a gas tank problem. Once I get the new gas tank I'll be sitting on seat springs but this baby still has a lot of "snap" for an old car, and I will be driving it. I am putting a 727 trans, 8 3/4 rear end sure grip with a 4:89 gear. Have to convert to a 5 lug 4 1/2 pattern. Complete restoration in and out side! This car will fly! A Bodys forever!
Art Clark III
 
I used the Isky E-4 in my 273 and I'm pretty happy. Just depends on how much of a hot rod you want to build.
 
b67cuda said:
Thank you all for the help - I am leaning twords the comp cams BUT I dont know if I should go with the .468 lift or the .495 -- What do you guy think ??
I will be runng 3.55 sure grip, 4sp, trying to stay with stock exhaust?
Click to expand...

My vote was going to be for a Comp Cam.
I would lean towards something in the "XE" Extreme Energy line.
Call Comp Cams, give them your cars stats, and let them help you choose a cam.
 
This is Art Clark III. I contacted Camcraft about a 273 cam because I obtained a lot of confusing information on the "D" Dart. One bulletin dated April 18, 1966, said the cam was a 284* duration and gave some other numbers, valve open and close but no lift data. And, continued to recommend the use of a adapter plate and bolt on a Holley #4160. The person from Camcraft agreed that the cam for the 273 "D
Dart was confusing. I think Chrysler did this on purpose? The stock 273 4 barrel motor has a solid 244* duration with a 475 lift.
Other information on the "D" Dart was a duel quad set up with 392 Hemi valves in the stock heads at 12.5-1 compression and suggests "ringing" the heads? And, went on to define this car as a SS/D car?
I found a lot of info on www.seriousviewers.co,/D-Dart/infoball.jpg.
Also, on youtube there is a 66 Dart video. The Dart runs a 408 cu in motor with a "904" tranny, 4:56 gear. 10.64 in the 1/4 mile @ 123 mph! This car runs a 6.71 1/8 mile.
Now this Dart is a runner!
I don't know yet which motor I am going with but I have an 8 3/4 housing and will use it soon as I can set it up with springs, center section and Wilwood disc brakes. Have to have the offset before you can order the brakes? And, I will use a 727 tranny, the cost isn't all that much for the durability factor.
 
Add my vote for Isky cams. When I was looking for one with the same specs as the stock commando cam, I found they had one the closest and it worked great.
 
Art, Here's the E-4 specs from the Flatlander racing website:
E-4 Tremendous torque & good mid-range power. 9-10.5:1 compr. , good idle stock converter. 3.23-3.70 axle ratio. Up to 625 Carb. RPM-Range (2000-5500) Valve Lift (.425 .425) Valve Lash hot (.015 .015) ADV Duration (260 250) .050 Duration (216 216) LC 108
If you're looking for a replacement cam for your stocker, this is the closest solid lifer cam I could find.

Schneider makes one a bit bigger that I would like to try:
#14202 Mild idle. 1500 - 5000 RPM. advertised duration: 264 deg. 224 @ .050 .480" lift 110 deg.
I have a 4 speed with 3:23's
 
Toolmanmike, I'm one of your fans. Your 273 build is admirable. I have not gone so far in my own build. All bearing surfaces etc were ok, so I chose not to grind the crank or bore the motor. Do you have opportunity to provide me feedback on my combo:
- D4B Edelbrock intake, 4 bbl dual plain
- Edelbrock 1406, 600 cfm intake
- Comp Cams cam part # 20-246-4, dur @ .015 270/270, 224/224 dur @ .050
- Electronic ignition
- Domed pistons, comp. ratio of 10.5:1
- Spitfire headers
Is good or not?
 
Djakken said:
Toolmanmike, I'm one of your fans. Your 273 build is admirable. I have not gone so far in my own build. All bearing surfaces etc were ok, so I chose not to grind the crank or bore the motor. Do you have opportunity to provide me feedback on my combo:
- D4B Edelbrock intake, 4 bbl dual plain
- Edelbrock 1406, 600 cfm intake
- Comp Cams cam part # 20-246-4, dur @ .015 270/270, 224/224 dur @ .050
- Electronic ignition
- Domed pistons, comp. ratio of 10.5:1
- Spitfire headers
Is good or not?
Click to expand...
Thanks for the kudos Djakken.
It sounds like a fun combo. I like that cam but you might find the cam a bit much unless you have a standard trans. or a small stall converter. I find it recommended for 340 and 360 motors. 273's can't handle too much cam especially with a stock converter and rear gear. Has anybody else out there ran this cam? The intake and carb are a good match too. You are one of the lucky few that own that intake. tmm
 
toolmanmike said:
Art, Here's the E-4 specs from the Flatlander racing website:
E-4 Tremendous torque & good mid-range power. 9-10.5:1 compr. , good idle stock converter. 3.23-3.70 axle ratio. Up to 625 Carb. RPM-Range (2000-5500) Valve Lift (.425 .425) Valve Lash hot (.015 .015) ADV Duration (260 250) .050 Duration (216 216) LC 108
If you're looking for a replacement cam for your stocker, this is the closest solid lifer cam I could find.

Schneider makes one a bit bigger that I would like to try:
#14202 Mild idle. 1500 - 5000 RPM. advertised duration: 264 deg. 224 @ .050 .480" lift 110 deg.
I have a 4 speed with 3:23's
Click to expand...

I've tried shopping cam shafts a few times in the past Too agrevating for me.
Do you know who has the best price for a hydrolic version of Isky E4 specs ?
 
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