Mopar 273 Commando projet, Mopar Magnum valves, Stroker sleeper, Mopar 920 heads

[PRH]

I’m sure there have been some really mild iterations built here since the Ede SMB heads have been on the scene(the OG aluminum replacement head), but I don’t recall any specifics.

I do recall a few of the “Hotter” SS/bracket race builds though.
My experience is that without any type of extraordinary efforts or exotic parts, power levels of 525hp+ are pretty easily achieved.
No bigger than supplied valves, no Herculean porting efforts, no tubes…….. just a decent vj and enough porting to get into the 265-270cfm range(which is way way less work on these heads than any factory iron head).

The easy button for ported iron heads in an application like what Charles customer is building, is to start out with some x/j style heads and have them cnc ported by Dave at KG Engines.
30+cfm more than the 920’s in this thread.

 

[273]

I don't agree with it, because it's misleading. Guys trust this **** and copy it, spend lots of time and money, only to get **** results.

Just calling a turd a turd.

Why should anyone run stock SBM heads:

I see what your saying but I never said they should, I just find it interesting what people can do with them, I'm in the more information the better camp. As for it leading people astray unfortunately that's up to them to work through, even good info leads people astray they can become over focus on one or two or so bits of info and are blinded by it like Torque, CR, velocity etc.. Velocity I find funny because people warn of it's importance but generally have zero idea of how much you have or should be shooting for, just smaller is better.

 

[PRH]

To help illustrate how far behind you’re starting out by using the 920 vs the x/j heads……..

-Untouched J head from the factory, used valve job and factory tulip style 2.02 valve is typically in the 200cfm range.

-Installed 11/32 guides and tested using a 2.02” SBC valve………. Seat machined and added a 75* bowl cut…….. leaving this as a starting point for porting.

Even this flows 215cfm-

-Basic clean up of entire port, no guide boat-tailing, no chamber mods…….. 250+

 

[junkyardhero]

I'm in the more information the better camp.

at what point does information just become noise?

 

[Newbomb Turk]

at what point does information just become noise?

It’s only noise to those who ignore it.

 

[junkyardhero]

It’s only noise to those who ignore it.

i'm sorry what were you saying? i wasn't paying attention...

 

[Newbomb Turk]

i'm sorry what were you saying? i wasn't paying attention...

lol. I see you are starting the new year off full of piss AND vinegar!

 

[junkyardhero]

lol. I see you are starting the new year off full of piss AND vinegar!

every great journey begins with the first step!

besides, i learned from the best! ;D

 

[273]

at what point does information just become noise?

I'd say it depends on the individual, even good information can be noise if you could careless about it and bad information can be valuable in not what to do and some information don't become valuable until you learn something else.

 

[stroker402]

last winter when I was building another 273 I worked the 920 heads over with just cleaning up on the ports rough surfaces and flashing and gasket match and I picked up alot more hp just by doing those steps... no valve job either. enough power to take on my buddies and come out ahead in a street race ... we were even before. those were abodies 67cuda and 70duster 70 swinger. cuda has built 340 with x heads , built 360 in a 70 dart swinger and a stock magnum 380 hp 70duster 3500 stall headers 391 gear flows. no one has beat my 65 barracuda formula S 273 so far. it's a 273 screamer ! read my post "273 command build" . You just can't tell me that 273's have NO POWER. most people here have no clue what a 273 is capable of doing. all they do it cut them down. AND I ONLY BUZZ IT TO 58OO RPM SHIFTS.

 

[Mean416]

To help illustrate how far behind you’re starting out by using the 920 vs the x/j heads……..

-Untouched J head from the factory, used valve job and factory tulip style 2.02 valve is typically in the 200cfm range.

-Installed 11/32 guides and tested using a 2.02” SBC valve………. Seat machined and added a 75* bowl cut…….. leaving this as a starting point for porting.

Even this flows 215cfm-

View attachment 1716494758

-Basic clean up of entire port, no guide boat-tailing, no chamber mods…….. 250+

View attachment 1716494759

And you think, if I pick up a die grinder myself, I'll be able to reproduce these results? And how many hours involved? (I know the answer - no. And I also know I'd have 30-40 hours wrapped up in the deal.)

Better to go with speed master or the like.

 

[stroker402]

And you think, if I pick up a die grinder myself, I'll be able to reproduce these results? And how many hours involved? (I know the answer - no. And I also know I'd have 30-40 hours wrapped up in the deal.)

Better to go with speed master or the like.

that was my winter project .. it took me months , a little each day . and did a lot searching on the internet what to do and Not to do to get it right . big improvement !

 

[Mean416]

To each his own. I couldn't afford to devote that kind of time to something like that

 

[273]

 

[PRH]

I’ll give it to Charlie for having the patience to chase 1’s and 2’s.
For me that seemed to always turn into me putting in time I didn’t get paid for.

I’ve said it before, and will continue to……..
I like the most gain for the least work.
I’m not chasing any 1’s, 2’s, 3’s.

My post above about choosing the J head over the 920 was in no way a recommendation for people to port their own heads.
The people who are going to go down that path will do it regardless of what they see here.
It was more of a message about making your efforts yield better results with less labor by starting out with something that’s closer to the desired finished results to begin with.
“Work smarter……. Not harder”

For those that aren’t sure if they want to try it or not……..basically my answer is “don’t do it”.
If you want to determine which side of the fence your porting desires land, get a scrap head similar to what you’re planning to build, and start grinding.
A few hours grinding time should provide some clarity.

 

[Newbomb Turk]

I’ll give it to Charlie for having the patience to chase 1’s and 2’s.
For me that seemed to always turn into me putting in time I didn’t get paid for.

I’ve said it before, and will continue to……..
I like the most gain for the least work.
I’m not chasing any 1’s, 2’s, 3’s.

My post above about choosing the J head over the 920 was in no way a recommendation for people to port their own heads.
The people who are going to go down that path will do it regardless of what they see here.
It was more of a message about making your efforts yield better results with less labor by starting out with something that’s closer to the desired finished results to begin with.
“Work smarter……. Not harder”

For those that aren’t sure if they want to try it or not……..basically my answer is “don’t do it”.
If you want to determine which side of the fence your porting desires land, get a scrap head similar to what you’re planning to build, and start grinding.
A few hours grinding time should provide some clarity.

Yup. And it may not even take a few hours lol.

 

[PRH]

Probably would depend on how close the expectations are to exactly how much fun they’re actually having and/or how well they’re set up to get the job done.

I’ll add this……..
I watched Charlie’s new Die Grinder evaluation video.
If I had to use a big cumbersome thing like that do do porting, I never would have gone down this path.
I’m spoiled with my air mini-die grinders.
Yes, you need a fairly big noisy air compressor……. But I have one of those.
Been using that style from the start. Too late to change now.

 

[Newbomb Turk]

Probably would depend on how close the expectations are to exactly how much fun they’re actually having and/or how well they’re set up to get the job done.

I’ll add this……..
I watched Charlie’s new Die Grinder evaluation video.
If I had to use a big cumbersome thing like that do do porting, I never would have gone down this path.
I’m spoiled with my air mini-die grinders.
Yes, you need a fairly big noisy air compressor……. But I have one of those.
Been using that style from the start. Too late to change now.

Yep. I can’t swing that big grinder for hours on end either.

 

[stroker402]

Yep. I can’t swing that big grinder for hours on end either.

yeah that big gaudy electric grinder is toooo big.. I used a tiny little electric dremmel tool... worked just fine no issues. 1/4" bits. to each his own.

 

[PRH]

I don’t even own an electric die grinder.

For me, it’s about finding the balance between something with enough power to do some amount of “hogging”, vs being small enough for easy control to do detail work vs light enough for fairly long term use.