318 power?

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74 dart sport

Kameron
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Hey guys! I have a question for anybody out there. I would like to know what the net HP/ torque on my engine might be. Here's the stats: 1967 318 (gross: 230 hp, 340 tq). Hooker full tube headers( will have h pipe , 2.5 inch tubes, and flowmaster hp-2 mufflers. Edelbrock 600 cfm carb and edelbrock performer intake. Bored .20 over . Has a mild/large cam. No AC or any emissions equipment. Thanks!
 
The net hp is probably close to the stock gross power after those mods
 
I get 232.5

Of course it's bs.
But it won't be much more;unless "Has a mild/large cam", really means flippin big.

But forget the numbers. For a streeter,big numbers just means blowing through the tires sooner and harder.
Slam it in, tune it, and DRIVE that baby.

I've had an awful lot of fun, with a totally stock teener long block, with nothing more than; a TQ, headers, a 2400TC,and 3.55s, in a pig-heavy 68 Barracudafb(3850/me in it).And crazy big fun with a 3.09low/4-spd. and 3.91s.
 
What AJ said. Forget the numbers for now. Drive it, tune on it, drive it some more. You may find you got all the power you need. Amazing what non-engine mods (gears, torque converter...)can do for seat-of-the-pants fun in a well tuned street car. Save the 'big power engine' for later...
 
What is missing from your description is compression and actual cam specs. What's the duration and lift of the cam? It could be about 255 HP with bolt on's. The right cam is good for another 20 hp for a possible 275HP. The wrong cam could cost power or move more power in at a unusable rpm range.

To many variables
 
the number you are looking for on the street is Torque.
now if your going to pass the big end regularly you want a big hp
number along with a matched drivetrain for 1/4 mi..gears,converter...
 
Well, we picked up the engine from a guy on Craigslist along with a 727 TorqueFlite Tranny. The engine is in great shape (zero decked, cross hatch markings still visible.. etc..) . All we know about the cam is that its on the larger side (its all dark and has yellow on the end connecting to the distributor). The engine was run before, so at least we do know the cam works. Also, we just took in the tranny and had it fully rebuilt and a TransGo kit put in. We are using a torque, not stall converter. It has the stock 2.76 gears in the diff (peg leg). Now the question is: Should we get a Posi Sure-grip diff with 3.23/3.55 gears or just leave as is.
 
Kinda depends on what you want to do.
Since we really don't know anything about the cam, why not wait and see.
It is my opinion that if the cam is just one or two sizes over stock then you may be able to control wheelspin with larger tires.But it won't be particularly quick out of the gate with the 2.76s, and a stock TC. But if you are just gonna cruise it, then wait until you you have had a chance to drive it.But, if the cam is any bigger than that, then a rear gear change and/or a higher stall TC will very likely be desired.
- On the otherhand, if you wanna have some fun, then a 3.55SG and a 2400TC are a fun place to be with a warmed up teener. And if you really wanna wake it up a3.91SG will be a blast. - But if you need to spend significant time on the hiway, then 3.23s or less will be nice.

- Performance gears do several things, the top three being; 1) they trade away cruise comfort, for off-the-line giddy-up, and 2) they allow the engine to rev up a little quicker, which accelerates the car a little quicker, and 3) they make your engine feel bigger.
Additionally; the higher cruise rpm sometimes leads to heat,wear,noise, and vibration issues.
- As to #1) the switch point is about 3.55s. Cruising with these and 27 inch tires puts the Rs at 2867@65 locked up.I cannot say where the automatic might slip to.Some guys are ok with this, others like me, not so much. Plus it won't get any awards for fuel savings.
- As to #2) Quicker is funner.
- As to #3) 3.55s will make your engine seem 3.55/2.76 =about 28% bigger! This is a huge improvement.
- As to the SureGrip; You might be able to get away with a non-SG with 2.76s to 3.23s,the stock TC,and decent big tires. But it really depends on your driving style, and the engine output at stall. Which is very dependent on cam size, and,of course, the stall rpm. I would be adopting a wait-and-see approach. Well that's not quite right, but it's what I recommend for you.
 
Ok, Thank you AJ. Even if the cam is only a bit bigger and we stay with 2.76, it should still be a fun car to drive. It is my first car, so I know Ill be happy and excited either way. But, I think one of the best parts will be driving into the high school parking lot, opening the cut outs, and blowing the ricer's minds lol. :)
 
74 dart sport said:
Thanks so much AJ, This helps a lot. I do have one question: what do you mean by "R's at 2867@65 locked up"?
Click to expand...

Rs are Rpm. I'm a 1-finger typer, so I take shortcuts whenever I can.
So here's the Formula; MPH = Rpm x TC /1056 x R1 x R2 where TC is tire circumference,and R1 is rear gear Ratio, and R2 is transmission selected gear Ratio, and MPH is miles per hour. So a 27 inch tire is 27 x 3.1416(Pi) = 84.8TC, and the rear gear selected is 3.55, and the tranny gear for cruising is 1.00. Plugging those all in and calculating; 65mph =2867Rs(Rpm)
Now locked up means this is the rpm with Zero TC (converter) slip. At cruising speed with an automatic transmission the Rs at a set cruise Mph, can vary quite a bit,depending on all kinds of things. Like the amount of engine power put into the TC,the TC design,the wind, the road surface, the road grade, and whether or not you're towing something. With a stock TC,The Rs could be 100,200,or even 300 different from the calculated Rs.Usually lower.Cuz the TC is slipping.

Now about those cutouts.......If you have not yet ordered them, GOOD.If they're already on there,that's too bad; You coulda spent the money on better things. But if it's always been your dream to blow the ricers minds, well then, have at 'em.
 
3.55s are plenty of gear for an automatic, behind a torquey teener.
You would hate 4.56s within a few short hours.
But I assume you were kidding!

With 23.4s and the current 2.76s; your hiway Rs works out to 2973@75,locked up. At 75 the TC will very likely be locked up.For me this would be unacceptable. I would be trying to fit some 28.0s in the back, to bring the Rs down to 2485locked up.Even that is buzzy for me. But here in Manitoba the speed-limit is mostly 100kph, which is 62 mph. For me that would be 62@2054 and totally acceptable.And so that's what I got!A final drive of 2.769. And 3.55s out back; hooray for overdrive!
 
Ben Drinkin said:
What AJ said. Forget the numbers for now. Drive it, tune on it, drive it some more. You may find you got all the power you need. Amazing what non-engine mods (gears, torque converter...)can do for seat-of-the-pants fun in a well tuned street car. Save the 'big power engine' for later...
Click to expand...

Exactly.. Enjoy it for now,learn as you go. Your boredom in acceleration rates,will tell you...
 
AJ/FormS said:
Now about those cutouts.......If you have not yet ordered them, GOOD.If they're already on there,that's too bad; You coulda spent the money on better things. But if it's always been your dream to blow the ricers minds, well then, have at 'em.
Click to expand...
Absolutely. Thing is it doesn't take much to make an SBM sound fantastic to most folks. Few will ever pick up on the small cam in the lope.

AJ/FormS said:
3.55s are plenty of gear for an automatic, behind a torquey teener.
You would hate 4.56s within a few short hours.
But I assume you were kidding!

With 23.4s and the current 2.76s; your hiway Rs works out to 2973@75,locked up. At 75 the TC will very likely be locked up.For me this would be unacceptable. I would be trying to fit some 28.0s in the back, to bring the Rs down to 2485locked up.Even that is buzzy for me.
Should be able to get 26s-27s for not too much, they'll likely not fit up front (but may with the V8 bars your car has), but it should bring the RPMs down to something not out in left field. Rebuilding and swapping to an overdrive transmission from an '89-'95 truck would be a nice improvement that'd let you have your cake and eat it too. Steep 1st, steep 2nd, .69 overdrive. With 28.1s and a .67 overdrive I really liked the speeds with 3.73s in the mid-upper 70s. I think like 2250. An A500 "42RH" with 3.73s in an 8-1/4 or 8.8 would be a pretty nice setup for a cruiser. LSD- for a street car I'd let whatever you can get your hands on determine that. If a readily available axle doesn't have an LSD in it- you don't need one. If it does have it, run it.

AJ/FormS said:
But here in Manitoba the speed-limit is mostly 100kph, which is 62 mph. For me that would be 62@2054 and totally acceptable.And so that's what I got!A final drive of 2.769. And 3.55s out back; hooray for overdrive!
Click to expand...
70 for most of the roads out here. So rolling out with traffic over that shouldn't ever be obnoxious. It very much falls into the category of no overdrive- don't spend the money to lower your fuel mileage and increase your RPMs. Sure it'll be more fun but not like it'll be without compromise- just gotta know what fits best into your needs.
Click to expand...
 
My car only has 15 inch rims, so sadly, there aren't many options (most are for minivans ��). Plus, we just bought new tires . Most of the time, we cruise at 80-85 mph
 
Oh, dude, you are so screwd...

I used to have two sets of tires(three actually with the DragRadials). One set for city bombing, and then another set for the highway. Now I have overdrive.
For you, the difference from 23.8 to 28 would drop the hiway rpm to 85%. That would make 85mph, drop from 4262 locked to 3622 with 3.55s. Or with 2.76s the Rs would drop from 3314 to 2816. This 85% is about the same as 1.5 rear gear changes which in this range are about 10%.
3314 is awful buzzy. 2816 is ok for an hour or maybe two.
The faster you spin the engine the more important it is to have everything that is spinning well-balanced.Driveshaft,axles,wheels,clutch,and engine guts.Anything vibrating will soon make it's presence FELT.
The tire swap is kinda like an overdrive; which might reduce the rpm with 3.55s;from 4262 to between 3324@78%, to 2941@69%; and with 2.76s, from 3314 to between 2585 and 2287.
 
Danm head is melting from the math...errrrr ... Ugh,,, garg...
LOL
Dude! Just had an idea for real, do a graph!
 
A template you can bring up and fill in as needed. Kind of like a dyno graph except the sides would be blank to fill in with what ever is needed. Like percentages, speeds, mph, tire size on the one side, mph up top, just an idea.

It's easy to see a cam change on a dyno graph, 1 run on top of another.
The same could be done for your lessons which are really good by the way.
Just thinking out loud of course. Just teasing before with the math goofing.
 
What makes a street car fun? GEARS... 3:55 at least. 4:10 if you want a streetlight bandit.
 
rumblefish360 said:
A template you can bring up and fill in as needed. Kind of like a dyno graph except the sides would be blank to fill in with what ever is needed. Like percentages, speeds, mph, tire size on the one side, mph up top, just an idea.

It's easy to see a cam change on a dyno graph, 1 run on top of another.
The same could be done for your lessons which are really good by the way.
Just thinking out loud of course. Just teasing before with the math goofing.
Click to expand...

The material already exists, how do I get it into the forum? I'm pretty computer illiterate.

I understood the tease and I enjoy teases when they come.I really do. You guys can't hurt my feelings.
 
AJ/FormS said:
The material already exists, how do I get it into the forum? I'm pretty computer illiterate.

I understood the tease and I enjoy teases when they come.I really do. You guys can't hurt my feelings.
Click to expand...

I am computer illiterate myself. Don't know how to go about it ether.
Outside of a manual entry or use of the forums a ilty to massage replies, sorry, IDK.



needsaresto What makes a street car fun? GEARS... 3:55 at least. 4:10 if you want a streetlight bandit.
Click to expand...
Couldn't agree more. Love my street light bandit gears.
 
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