MILO
Well-Known Member
Im all set for my next project just need to find the correct car or truck I have a 273 that I rebuilt all ready for the road its still on the stand
64 barracuda 273
- Thread starter Shippy
- Start date
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Why ?
Dan the man
Well-Known Member
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 24,917
- Reaction score
- 12,269
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 24,917
- Reaction score
- 12,269
With the Commando A833 and 3.55s; my speed at 2800, in each gear is ;
20/33/45/63/81 in overdrive.
When I shift 1-2-3-3od-4od; the
Rpm drops are about 1060/760/620/1340 into 4-od, so, sometimes I carry First a lil longer, but mostly not.
I just like that 2000>2800 pull; the engine is just getting on the timing, and humming a happy tune thru the dual 3" pipes..
Ignition Timing is 28@2800 on the mechanical plus initial, and the VA is adding 22, so long as the vacuum is up over 10/12 inches IIRC. So by 2800, all sources in, that totals 50*, she pulls like a tractor down there.
And sometimes, I mightta forgot to dial out the Timing Module, in which case, that thing adds another, up to 6* the way I have it set. And it/the Dial-Back, adds to the mechanical, so she'd be running 34* at 2800, plus up to 22VA=56*................. and there's 6 more still in the Second stage mechanical, that slowly comes in, from 2800 to 3400. When that's all in, and the Opto-timer is out, then, again, total is 34* after 3400, with up to 22 in the VA and up to 6 more for cruising which then totals
28 + 6 + 6 + 22VA= 62* available. Badaboom!
and there have been times that I have used it all, and wondered if it was enough.......
That's the way I roll.
Did I mention that my little 367 pulls like a tractor down there? I meant; pulls like a tractor with the throttle barely open.
That's how I marry Power, Torque, and Fuel Economy, all in the same engine, Normally Aspirated. Well that and up to 195 psi cylinder pressure with as little as .028 Quench........ and lots of amps coming out the SuperCoil.
ohhhhhhhhhhhhhhhhhhhh but you know, it ain't a 340, so a lotta carshow folks ***** and moaned about that, until I told 'em it has a bore of 4.04, and 3.58 crank in it, so technically, it's the same as a stroked 340, and suddenly I stopped hearing "you shouldda built a 340."
Not to forget to mention, that KB107s scale at 502 grams, versus the 340 forged slugs at 745 IIRC...........
So you wanna talk throttle response?
20/33/45/63/81 in overdrive.
When I shift 1-2-3-3od-4od; the
Rpm drops are about 1060/760/620/1340 into 4-od, so, sometimes I carry First a lil longer, but mostly not.
I just like that 2000>2800 pull; the engine is just getting on the timing, and humming a happy tune thru the dual 3" pipes..
Ignition Timing is 28@2800 on the mechanical plus initial, and the VA is adding 22, so long as the vacuum is up over 10/12 inches IIRC. So by 2800, all sources in, that totals 50*, she pulls like a tractor down there.
And sometimes, I mightta forgot to dial out the Timing Module, in which case, that thing adds another, up to 6* the way I have it set. And it/the Dial-Back, adds to the mechanical, so she'd be running 34* at 2800, plus up to 22VA=56*................. and there's 6 more still in the Second stage mechanical, that slowly comes in, from 2800 to 3400. When that's all in, and the Opto-timer is out, then, again, total is 34* after 3400, with up to 22 in the VA and up to 6 more for cruising which then totals
28 + 6 + 6 + 22VA= 62* available. Badaboom!
and there have been times that I have used it all, and wondered if it was enough.......
That's the way I roll.
Did I mention that my little 367 pulls like a tractor down there? I meant; pulls like a tractor with the throttle barely open.
That's how I marry Power, Torque, and Fuel Economy, all in the same engine, Normally Aspirated. Well that and up to 195 psi cylinder pressure with as little as .028 Quench........ and lots of amps coming out the SuperCoil.
ohhhhhhhhhhhhhhhhhhhh but you know, it ain't a 340, so a lotta carshow folks ***** and moaned about that, until I told 'em it has a bore of 4.04, and 3.58 crank in it, so technically, it's the same as a stroked 340, and suddenly I stopped hearing "you shouldda built a 340."
Not to forget to mention, that KB107s scale at 502 grams, versus the 340 forged slugs at 745 IIRC...........
So you wanna talk throttle response?
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 24,917
- Reaction score
- 12,269
Throttle response;
as to the bad stuff;
>If you got a low-stall 727, forget throttle response, there is so much flywheel there, a 273 can barely turn it.
>If you got small-port heads and a 2-bbl, forget throttle response. the air just can't get in.
>If you got a tiny low-lift cam, or yur running a hot underhood air intake; you'll be measuring rpm rise with a sundial.
>If your throttle is too far open at idle, or your flywheel is off a truck, the rpm will take forever to come down.
>If your crank is running in the oil, holy cow that thing will rev slow and suck power.
> if you got so much blow-by, that the PCV can't deal with it, the pistons have to pump it around.
>If your engine can't get the old air out, cuz the exhaust is wheezing thru an old collapsed-baffle, 3-pass muffler, or a pinched pipe or worse somebody did a horrible job on the Y-pipe when converting to dual exhaust, well then, the fresh air can't get in either, and so, your throttle response is abysmal.
> if your distributor has a long-slow timing curve, as the smoggers do, well, there goes your cylinder pressure, without which, the engine is a slug.
As to the Good stuff.
>A light reciprocating weight is great, but as the engines get bigger, too light leads to broken parts. For a streeter their are other alternatives.
> For a streeter, that drives his car on the street, NOT a street-Racer; or a DD, the number one thing to consider, is that she's a two-gear car, and with street gears plus auto-trans, a lousy Second Gear is the Result. So throttle response is like, what? who cares.....
> just make everything big, get a deep-sump oilpan a tray, and feed her fresh air;
get a Manual trans with a lightweight Flywheel, race gears in the back, and yur done.
> and when you get tired of stalling the engine all the time, just put the Factory tank-flywheel back in.
> oh, and run a double-pumper carb.
> then razor tune the thing.
other
the KB107 360 pistons are about as lightweight as you can get, that's where I'd start. Except for the 273/early 318 rods, the rest of the factory rods are all made from the same castings.
If you have to have an automatic, use the A904, the parts are absolutely petite compared to the 727, and the small 904 convertor, hardly weighs anything.
After that, headers and true duals, gets the bad air out, while Bigport heads, and a modest cam, with fresh cold air, gets the good air in.
Then consider your gearing .
After that, the rest is in the tune.
As to gearing;
why do people install 6000+rpm cams in cars that can't legally get to 6000rpm in Second gear, in a streeter? Hmm? If the speed limit is 65, and you want to cruise longer than a short hop, then 3.23s are the gear of choice for most of us.
Well, with 3.23s and 27" tires, 65= 2700@3% slip. But
65 in Second gear is only 4200 @WOT. Which is just barely getting on the Torque curve. You see the problem?
In first gear, with a decent stall, anything bigger than a modest 318 is gonna smoke the tires if not nearly right thru First gear, then a good ways into it ...... soooooo why install a 6000 rpm cam?
So far, that HotRod cam;
is not needed in First gear,
cannot be used in Second gear, and,
on the 1-2 shift, the rpm is gonna drop into the basement at 59%. So if you did rev it to 6000 in first, the Rs are gonna drop to 3540, and your convertor can't help you pull out of that hole,
and 6000 in first gear get you to 55mph anyway.......
while 6000 in Second will go to 93mph, and you better have picked a cop-free zone, cuz if not, and you get caught, then you may be walking for a very long-time.
So then, IMO, Either the 6000 rpm cam goes, or the 3.23s gotta go.
If the 3.23s go, this 6000 rpm combo really wants 4.88s to 5.13s so yur looking at getting an overdrive.
But if you cut the rpm back to 5000, with a cam peaking at 4700, now yur looking at 3.91s, to hit 65@ 5100. Now you just have to figure out how to make enough power with a 4700rpm cam, to satisfy your ChitsnGiggles-meter. Of-course cruising with 3.91s is still a PITA, so the overdrive is back on the table.
Is it any wonder that strokers have become so popular? I mean, 440 plus ftlbs at 4000, makes 3.73s instantly possible, which means 3.55s are only a kiss away. So now, you no longer need an overdrive. So then, what you don't need to budget for an overdrive, that will about pay for the stroker kit.
I mean, for the guy who wants it all, and has the means, a stroker is clearly the way to go.
Course if you have a manual-trans, that's a whole nuther conversation.
as to the bad stuff;
>If you got a low-stall 727, forget throttle response, there is so much flywheel there, a 273 can barely turn it.
>If you got small-port heads and a 2-bbl, forget throttle response. the air just can't get in.
>If you got a tiny low-lift cam, or yur running a hot underhood air intake; you'll be measuring rpm rise with a sundial.
>If your throttle is too far open at idle, or your flywheel is off a truck, the rpm will take forever to come down.
>If your crank is running in the oil, holy cow that thing will rev slow and suck power.
> if you got so much blow-by, that the PCV can't deal with it, the pistons have to pump it around.
>If your engine can't get the old air out, cuz the exhaust is wheezing thru an old collapsed-baffle, 3-pass muffler, or a pinched pipe or worse somebody did a horrible job on the Y-pipe when converting to dual exhaust, well then, the fresh air can't get in either, and so, your throttle response is abysmal.
> if your distributor has a long-slow timing curve, as the smoggers do, well, there goes your cylinder pressure, without which, the engine is a slug.
As to the Good stuff.
>A light reciprocating weight is great, but as the engines get bigger, too light leads to broken parts. For a streeter their are other alternatives.
> For a streeter, that drives his car on the street, NOT a street-Racer; or a DD, the number one thing to consider, is that she's a two-gear car, and with street gears plus auto-trans, a lousy Second Gear is the Result. So throttle response is like, what? who cares.....
> just make everything big, get a deep-sump oilpan a tray, and feed her fresh air;
get a Manual trans with a lightweight Flywheel, race gears in the back, and yur done.
> and when you get tired of stalling the engine all the time, just put the Factory tank-flywheel back in.
> oh, and run a double-pumper carb.
> then razor tune the thing.
other
the KB107 360 pistons are about as lightweight as you can get, that's where I'd start. Except for the 273/early 318 rods, the rest of the factory rods are all made from the same castings.
If you have to have an automatic, use the A904, the parts are absolutely petite compared to the 727, and the small 904 convertor, hardly weighs anything.
After that, headers and true duals, gets the bad air out, while Bigport heads, and a modest cam, with fresh cold air, gets the good air in.
Then consider your gearing .
After that, the rest is in the tune.
As to gearing;
why do people install 6000+rpm cams in cars that can't legally get to 6000rpm in Second gear, in a streeter? Hmm? If the speed limit is 65, and you want to cruise longer than a short hop, then 3.23s are the gear of choice for most of us.
Well, with 3.23s and 27" tires, 65= 2700@3% slip. But
65 in Second gear is only 4200 @WOT. Which is just barely getting on the Torque curve. You see the problem?
In first gear, with a decent stall, anything bigger than a modest 318 is gonna smoke the tires if not nearly right thru First gear, then a good ways into it ...... soooooo why install a 6000 rpm cam?
So far, that HotRod cam;
is not needed in First gear,
cannot be used in Second gear, and,
on the 1-2 shift, the rpm is gonna drop into the basement at 59%. So if you did rev it to 6000 in first, the Rs are gonna drop to 3540, and your convertor can't help you pull out of that hole,
and 6000 in first gear get you to 55mph anyway.......
while 6000 in Second will go to 93mph, and you better have picked a cop-free zone, cuz if not, and you get caught, then you may be walking for a very long-time.
So then, IMO, Either the 6000 rpm cam goes, or the 3.23s gotta go.
If the 3.23s go, this 6000 rpm combo really wants 4.88s to 5.13s so yur looking at getting an overdrive.
But if you cut the rpm back to 5000, with a cam peaking at 4700, now yur looking at 3.91s, to hit 65@ 5100. Now you just have to figure out how to make enough power with a 4700rpm cam, to satisfy your ChitsnGiggles-meter. Of-course cruising with 3.91s is still a PITA, so the overdrive is back on the table.
Is it any wonder that strokers have become so popular? I mean, 440 plus ftlbs at 4000, makes 3.73s instantly possible, which means 3.55s are only a kiss away. So now, you no longer need an overdrive. So then, what you don't need to budget for an overdrive, that will about pay for the stroker kit.
I mean, for the guy who wants it all, and has the means, a stroker is clearly the way to go.
Course if you have a manual-trans, that's a whole nuther conversation.
Last edited:
What would a Stroker Crank in a 273 be? A Slug or a Compression Happy motor that didn't want to Rev anymore?
Why? It would be a 336 with 4" not overly huge, wouldn't be ideal but bet you could still get enough air in there to spin it fairly high.
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