A small port like that flowing 233 cfm must of had fairly high average velocity.
Mopar 273 Commando projet, Mopar Magnum valves, Stroker sleeper, Mopar 920 heads
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PRH
Well-Known Member
When that job is all said and done, I’d love to know how many hours he invested in it………. And what the bill was 
When that job is all said and done, I’d love to know how many hours he invested in it………. And what the bill was
Whatever he’s charging it’s probably not enough
PRH
Well-Known Member
I agree.
It’s one of those situations where his overhead is pretty low, so he could charge well below market value……… but does he?
PRH
Well-Known Member
I’m pretty sure it is indeed a “side hustle”.
Crazy how many man hours have been poured into projects like this. Not just the guy porting these heads, but all the copycat misinformed guys that will be working their *** off only to get - at best - marginal improvements.
Some myths need to laid to rest. One is that 302 heads - and really - any LA heads - are worth messing with beyond the most basic cleanup work. Sure...debur the rough spots, do a rough port match, get the valve job sorted out correctly. That'll get the average joe results.
Another myth is that anything beyond really basic port work, done by the average joe, will yield good results. If I've learned anything at all on this forum it's that porting these heads really requires a flow bench, lots of experimentation, and experience.
Some myths need to laid to rest. One is that 302 heads - and really - any LA heads - are worth messing with beyond the most basic cleanup work. Sure...debur the rough spots, do a rough port match, get the valve job sorted out correctly. That'll get the average joe results.
Another myth is that anything beyond really basic port work, done by the average joe, will yield good results. If I've learned anything at all on this forum it's that porting these heads really requires a flow bench, lots of experimentation, and experience.
NC Engine Builder
Grumpy Old Man
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I did a set of "302" heads a few years ago for a FABO member, and I did flow them when I was done, but the numbers were quite disappointing, I threw my notes away on those.
You don't need much more than a little common sense porting for improvements.
This: but all the copycat misinformed guys that will be working their *** off only to get - at best - marginal improvements.
ValiantRacing
Well-Known Member
I have been working to get my 273 with all stock parts to run the best it can for the last 10 years, it has not been easy, but i did get it to run a low 12s
How high in the rpm's do you have to turn to do low 12's with a 273 ?
all of them
if you've been following along, it's a dedicated track car with something like a 4.5K converter and 4.88's backing up a damn stout motor.
ValiantRacing
Well-Known Member
Not as high as you would think, stock heads do not support high RPM's I shift at 6700 and go through the lights at 7300.
Nice. That’s street rpm right there.
It’s 2026 and people still haven’t learned that rpm is your friend.
6700 and 7300 is perfect for a bracket car that wants lots of runs and maximum TBO.
Engines that peak 6,500-7,000 rpm's on the dyno always seemed to have an ideal power curve to me for a performance street strip engine, but a lot say they will have a terrible bottom end torque (hp) even though I don't usually see that in the dyno results.
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:
1. You're just building a basic street cruiser or a restoration - you want a stock appearance. Your regular 300-350 hp budget build. Not a damn thing wrong with it. And doesn't require anything beyond good valve job.
2. You're in some kind of spec racing class. In which case you're spending mega bucks on old iron. This stuff is actually cool because people get wild results. But it's not something a normal dude can replicate.
There's no other reasons to mess with the iron heads. Go speed master black Friday deal and move on.
I would argue (but I can’t say definitely because of extenuating circumstances) that I can make at least the same power with a 587 casting as I can with any chicom head. I think more.
The chicom head has an assbackwards chamber. I consider it a big step back from what Chrysler did with their “open” chamber that everyone hates. IMO the chamber in these chicom heads is borderline garbage for making power.
Without doing a serious amount of welding and the handwork to get the chamber back in shape, the chamber cant be fixed.
Same with the ports. You’d need to knock the guides out, slide in some consumable aluminum “guides” with a pilot hole in the top so you can find your center again without dialing everything in on a mill and weld up the short turn and all around the guide boss, which is damn near nonexistent.
I have a set on my engine now and to say I hate them is a gross understatement.
It is looking like I’ll be working my *** off to make the power I thought would be the floor for my iron head with the speed master head.
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