273 Commando

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Barracuda67

Barracuda67

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So is anyone running a 273 commando engine? If so, you still at 10.5 compression and how's she run on pump gas?
My 273 has been bored 40 over and am only running a dished piston with 4-valve relief. Figure I'm down around 8:1.
So befor I order a set of pistons, I would like to hear a little feed back.
Thanks.
 
My HP273 runs on BP 93 octane with no ping. I set the timing at 10 deg./before.
toolman
 
I have alternated getting a tank of the cheap stuff followed by the hight octane stuff and had no problems. As long as I keep th efoot out of it, I could probably just use the cheap stuff. Go for 10.5-1, you will be so glad you did. I don't know where you can get these pistons other than custom made. Good luck.
 
Running stock 10.5's heads were shaved .010 no issues as of yet but no real miles on the car I do have a MSD adjustable timing control just incase
 
Stock 67 273 4bbl commando setup- no issues with the good gas!
 
I think it's the 273 combustion shape that is so efficient.
 
My 273 I built with 10.5/1 Egge pistons and an Isky cam #390144 (solids) and it ran on 87 with no problem. Keep in mind I'm at 6,000 feet.

Buy the way, that is a nice cam.
 
I'm running a bit more cam then that Isky
Mopar Performance 296° Mechanical: P4120655
.557 Lift (252* @ .050)
 
Mine was fully documented and I didn't want to alter it so I did keep the original 2V manifold. I would have loved to drop a performance 4V manifold on it but didn't. I did change it over to dual exhaust running 2-1/4" (mandrel bend) from the stock manifolds out the back. New valves, same rods, balanced, 3-speed on the tree, 22 MPG highway. I'll see if it running is is still out there in cyberspace where I posted it.

068 resize.jpg
 
Great lookin' motor. Hope you can find the video. I'd love to hear that Isky E-4.
I'm excited to find someone that used the Egge 10.5:1 pistons. Looking forward to hearing from you. Performance and fuel mileage too. Nice combo! toolman
 
Nice build MVR

I have built my engine with a stock bottom end with pocket ported 273 heads running dual valve springs. Car has a dual exhaust with a H pipe that was on there when I got it using stock manifolds. Only issue I had was that I didn't have the factory 4 barrel manifold so currently using a Edelbrock Streetmaster
 
Thanks for finding the video. That's the cam for me! If my Dyno 2000 software is even close I should get over 300 hp. toolmanmike
 
.030 over with 10.5 pistons, Isky E-4, at 4,500 ft elevation and the 904 tranny. No issues at all with compression.
 
I think I just went cast since it was just a "stock" 2-V build. Sure miss the ol gal. It sure sounded sweet. Alot of people though there was a big block under the hood.

Jim
 
I had to listen again..................Sweet!!!!
 
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