Anyone build a high RPM 273 using 2.02 size head?

[gagembassett]

I just built a 273 that will spin 8 but lightened my spring load and I keep the rev to 6 as the valve train was really tight and I was afraid that spring pressure was going to wipe out my mechanical cam.
Dyno was 355hp at 8 but with the new lighter springs it was 317hp at 6200rpm.
$10k to make that happen. Stock heads with some porting and stock sized valves. The larger valve will not help much because of the cylinder diameter is so small. Notching the block drops compression a tad.
I love my 273. But there is more HP for the same $ with the bigger CI motor.

You wouldn't happen to have a video of that sweet thing pulling 8k on the dyno? I'd love to see it!

 

[408 swinger]

Now that's something I'd love to see!

Matt Steen's Valiant. This is in Kearney, Ne. This pic stolen from Memike in the Random pics thread. Thanks, Mike!

 

[66fs]

I've built a 1.88 valve J head 273. Worked great, no proof, no time slips. 1972 340 J heads milled .040 and .038 in the intake side of the head, competition valve job, gasket matched on top and sides, cleaned up the bowls, chambers equalized to 64.8 cc. No bore notches, 10.5:1 TRW forged pistons, Speed Pro file to fit rings, bored and honed with torque plates, windage tray, HV 65 psi oil pump, Cloyes True roller timing chain, stock 340 cam, valve springs, shimmed rocker shafts, 71 340 intake and 4 speed TQ. Direct Connection electronic distributor and a chrome box. 340 flywheel and bellhousing, HP 440 10.95 scalloped clutch and pressure plate. 8 3/4 rear with choice of gears from 2.76 to 4.10. Shifted at 3,000 rpm minimum and 6,500 rpm regularly. All in a nondescript 1964 Barracuda. Most favorite car and engine ever!

 

[273]

I'd like to hear more about the 273 IQ52 built, I think it was 475 HP @7500 rpm.

"Stock 273 block 8 sleeves and 3.75 bore for 292 cubic inches
Stock crank
5.4 H-beam Ford rods with EDM pin oiling
Diamond custom pistons with crappy 1/16 ring package
Wet sump oil pan and HV pump with oil crossover
Iron magnum style engine quest heads w/roller rockers, jomar girdles and pushrod oiling
Comp solid roller cam and lifters
Lots better parts today to make way more power"

 

[Syleng1]

You wouldn't happen to have a video of that sweet thing pulling 8k on the dyno? I'd love to see it!

Let’s see if this works. I’m not sure of what pull this is. But it was one of the pulls at the machine shop- Larry’s machine in Groton Connecticut. Gary the owner is a good guy. Top notch crew. Most old school Mopar guys.

 

[Syleng1]

Seems I cannot get video to load. Let me see if my son tomorrow can upload to boobtube and then I can attach the link.
I think toolmanmike saw the video a few months back- maybe he can share it and if he has a copy.

 

[oldkimmer]

I seem to remember an old article in one of the Mopar rags of a 1967 Dart convertible. Running a 273 with X heads. Don't remember cam or intake. Want to say damn thing was in the 10's. Do remember that they specifically talked about the bore notch.

I have that article. That darn dart. Kim

 

[66fs]

Let’s see if this works. I’m not sure of what pull this is. But it was one of the pulls at the machine shop- Larry’s machine in Groton Connecticut. Gary the owner is a good guy. Top notch crew. Most old school Mopar guys...

What intake are you running?

 

[66fs]

An oldie but goodie.

67' Barracuda 273 (Camshaft Results at the Track)

 

[66fs]

There was also a early Barracuda vintage road racer with a serious 273 in the 400-500hp range. EQ heads and 13:1 compression and a custom racer Brown cam? From OZ?

 

[gagembassett]

So basically, a uber expensive custom build, which makes less torque than a junkyard 360 magnum, and a soft soggy power curve that would be miserable on the street.

why are you acting like this is the first time someone has made a full-on race engine? Not every build has to be done with logic, feasibility, expense savviness, and made to drive on the street..........

 

[replicaracer43]

why are you acting like this is the first time someone has made a full-on race engine? Not every build has to be done with logic, feasibility, expense savviness, and made to drive on the street..........

I never said it was the first time anyone built a race engine. I am just pointing out it has poor return for the investment is all.

 

[RustyRatRod]

I hear that he's having a rough time and recovering from the virus...

Is that what it was? I do hope he's ok. He ain't no spring chicken no more. I do hope he recovers completely.

You just caint even get sick and even in the hospital and people still don't give you a break.

 

[RustyRatRod]

I never said it was the first time anyone built a race engine. I am just pointing out it has poor return for the investment is all.

It doesn't sound like something I'd build but I'm not knockin it. Maybe he wants something with peak power at 7500 plus. Some people like to rev things. Ain't everybody stroker lovers.

 

[273]

So basically, a uber expensive custom build, which makes less torque than a junkyard 360 magnum, and a soft soggy power curve that would be miserable on the street.

I feel a lot of people would be happy with 473hp out of a 360 with EQ's and a roller cam, don't forget it's torque to the ground not at the crank a 273 is gonna need about two full ratio's deeper than a similar 360. Only real kind of trick thing would be 8 sleeves which could do similar without. Yes a 360 or 408 would make a better street machine, I think this engine in a early A body heavily gutted road race street machine with four gear and some really deep rear gears like 5.13 plus would be a fun car. I bet most people building a built 273 would be happy with a 100-200 hp less.

As for the 2.02, most would have a hard time using up what 1.78 valve could do, If I was gonna do 273 probably would use a pocket ported replacement magnum head.

 

[dibbons]

Impressive!

 

[Charrlie_S]

I don't remember all the specs, but Back in the '80's I had a 65 Valiant 4 door sdn with a 273/904/8 inch conveter/ 8 3/4 rear. Ran 12.8's about 104 mph. Tried the 360 heads. As someone else stated the loss of compression, offset the better breathing. Times were almost identical. If doing it today, I think I could have been better with the 360 head, as I would have done other work to get a better gain with the 360 head.
PS: The cam I was running was a Crane flat tappet, somewhere around 520 lift.

 

[66fs]

Everyone thinks I'm some kind of 273/318 hater, but that's simply not true. I have built numerous combinations of both, BUT the bottom line for MOST people is bang for the buck. So as a example, here is one I built back in 2017, and it has major restrictions. But for the sake of discussion, it is a .005 over 360, stock stroke, flat top piston, EQ heads very well prepared, but UNPORTED, with a 1.94 intake valve and a .420!!! Lift hydraulic flat tappet cam, a untouched performer 318/360 intake, with a holley 500 2 barrel carb. It cost my customer right at 6k at that time, parts, labor and dyno time. And unlike the 273 in the discussion which I think failed after a few pulls, this one is STILL running to this day.

I still don't know why you guys always "have" to add the 360 to every small block conversation. Like we have not heard it a million times before. 12 second quarters are 12 second quarters, or 10 second for that matter. I've had all the small blocks in HP form. Did not save one 360, and I had early ones and police ones with all the good stuff. If you can't contribute to the discussion, don't feel the need to add "the 360 is the best and only engine to build". Not everyone feels that way.

 

[toolmanmike]

I don't remember all the specs, but Back in the '80's I had a 65 Valiant 4 door sdn with a 273/904/8 inch conveter/ 8 3/4 rear. Ran 12.8's about 104 mph. Tried the 360 heads. As someone else stated the loss of compression, offset the better breathing. Times were almost identical. If doing it today, I think I could have been better with the 360 head, as I would have done other work to get a better gain with the 360 head.
PS: The cam I was running was a Crane flat tappet, somewhere around 520 lift.

I was curious so I ran your numbers on the Wallace Calculator. That car should weigh around 2600#. 104 mph @ 2600# =225.6 hp.
Now the other way around, 12.8 sec. @ 2600# = 245.4 hp. I would think the 245.4 is the more accurate of the two.

 

[66fs]

First of all, you obviously didn't read what I posted. And my post is there for comparisons sake, to give a example of the difference between a high RPM race type engine, and a engine designed to be a everyday driver. It's simply data, and without data, all you have is a opinion. I am a professional engine builder, I build every imaginable combination, and you wont be able to quote where I ever said that a 360 is the best and only engine to build. What have YOU contributed to this discussion?

I did read it and I did get what you said. Over and over and over again... I have built enough engines in my day, so what.

 

[Charrlie_S]

I was curious so I ran your numbers on the Wallace Calculator. That car should weigh around 2600#. 104 mph @ 2600# =225.6 hp.
Now the other way around, 12.8 sec. @ 2600# = 245.4 hp. I would think the 245.4 is the more accurate of the two.

Actually the car was heavier, I think about 2700 (model 200, 4 dr sdn) and I weighed about 170lbs. Also I'm not sure of the MPH. I do remember the ET though. Your talking about 40 years, ago. Also, if I remember correctly, I was geared too deep (I think that's why I tried the bigger valve heads, to get a little more RPM), and it might have been 108mph, but not sure.

 

[EdsWelding]

I remember a guy that raced at Quaker City Dragway near Salem Oh. by the name of Dave Baker with a 68 Dart stick shift that had a 277 winding motor in it that ran well into the 9's. Him & his Dad had an engine shop out that way somewhere, I think his Dad passed away. Smart guys both of them.

 

[pishta]

I've built a 1.88 valve J head 273. Worked great, no proof, no time slips. 1972 340 J heads milled .040 and .038 in the intake side of the head, competition valve job, gasket matched on top and sides, cleaned up the bowls, chambers equalized to 64.8 cc. No bore notches, 10.5:1 TRW forged pistons, Speed Pro file to fit rings, bored and honed with torque plates, windage tray, HV 65 psi oil pump, Cloyes True roller timing chain, stock 340 cam, valve springs, shimmed rocker shafts, 71 340 intake and 4 speed TQ. Direct Connection electronic distributor and a chrome box. 340 flywheel and bellhousing, HP 440 10.95 scalloped clutch and pressure plate. 8 3/4 rear with choice of gears from 2.76 to 4.10. Shifted at 3,000 rpm minimum and 6,500 rpm regularly. All in a nondescript 1964 Barracuda. Most favorite car and engine ever!

there is your recipe, right there! 340 auto or manual cam?

 

[pishta]

Lets just assume for this thread that your running in a stock class drag with a 'small' motor CID limit of 292 for the .010 over Ford guys....3xx need not apply.

 

[replicaracer43]

Ok, I deleted my comments, and my comparison, never intended for anyone to get triggered, the world has enough drama. Now, back to the high rpm 273! Peace out