“Best” all around axle ratio: ~450hp w/ A904?

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I have a suspicion that this engine makes more than 320 hp….
I had a very similar combo that on 245 street tires and with a 4-speed/3.55s went 106 in the quarter@3650 pounds. The Wallace Calculator points to 330 hp, so you might be bang-ON!, except ..... yes, I was shifting at 7000, lol.
This was a one-run deal with street tuning. It was a 2.5hr ride to the track each way so when it went 12.9 I did not care to know any more.
 
Definitely north of 320. I'd bet anything is makes north of 360.
 
I had a very similar combo that on 245 street tires and with a 4-speed/3.55s went 106 in the quarter@3650 pounds. The Wallace Calculator points to 330 hp, so you might be bang-ON!, except ..... yes, I was shifting at 7000, lol.
This was a one-run deal with street tuning. It was a 2.5hr ride to the track each way so when it went 12.9 I did not care to know any more.

Definitely north of 320. I'd bet anything is makes north of 360.
Thanks Gent’s. IF I ever get to dyno this engine (not happening) I’d hope for better than 360 hp. But IDK.
I took it to the track @ Orlando w/mderoy to dial in the car some. With 3.55’s on 26” tires and a tight converter I wasn’t expecting much. The best trap was 101 with a OE shifter that gave up the ghost after the first run. First run it fell on its face since the carb was a OOTB Summit 750. (AKA Holley 4010) Mike gave the carb pump shot a quick twist and said try that! It worked but the shifter would not go into first. I also never let the tire pressure down from the street driven 35psi. It was terribly slow but still fun. Just stab and run from idle.

I know there’s lots left in it but I have not been able to get into the track yet. Just do remember it’s a street driven car designed for easy driving and not racing the track.
 
When I leave in 2nd gear, from 1,200RPM, my car goes 11.50 vs. 10.98 leaving in 1st. I forget if it changed the MPH.
 
but still fun. Just stab and run from idle.
Like you said.
and For me, hands down the most fun and satisfying combo I ever built. Not to mention, with overdrive, made better point to point hiway fuel economy in summer, than anything I ever had before it; and only recently has it been tied by a 2.5l Direct Injected DOHC 4banger, the one in my 2012 Chebby Orlando 6speed auto.
I firmly believe that yours and mine are hands down, more engine than most streeters will ever need or want. Couple them with an extra gear for overdrive, and a re-geared back end, they make a fabulous combo. I would still be running it today since 1999, if the cam hadna lost lobes. Just one size bigger cam, cost me a lotta time and money, to get the fun back into the bottom end.
 
Go with a 2.76. Just think of how much better your gas mileage will be.
:poke:

2.76:1...don't laugh. A few years ago a fellow pulled in to our strip with a Duster running a 408. Promptly
ran an 11.76!
His rear gears were 2.76! Said his problem was traction!
 
Took the wife’s Cuda out to a car show. Besides the gaggle of disparaging remarks of how I screwed the car up royally, I was asked a host of questions on the engine.
I was told I have no clue what I’m talking about and it really makes *** hp.

I never dyno’d the engine and I really don’t care what the hp is.

.030-360 @ 11.5-1
Hyd roller at 224/230 -.573/.569-110
TF heads, rpm intake, 750, TTI headers -2-1/2 exhaust.

I’ve been given “Professional” parking lot HP ratings between 290 & 360 hp and my car can only run a 14- or up to a 12.5 in the quarter.

I did find it amazing how a few guys would rephrase that he same question 2-5 times.

How fast is it.
Never been to the track
What’s the trap speed
Aaaaa- never been to the track
What did it do for a ‘60?
So sorry, never been to the track
So how can you say it’s fast?
Ummmm, I never said it was or anything about how fast it is.
OK-OK, so what did it trap at?
(Repeat the above twice.)

Yea… actual conversation

When asked about the HP. IDK, never dyno’d it, you d guess north of 320? IDK. Then I get all the parking lot “Pro’s” giving me there vast experience…. LMAO!

I’ve been putting engines together since I’m 19/20 YO.
I stink at the guessing posts here. However I’ve been in more than just a few cars. I have a suspicion that this engine makes more than 320 hp….
But every last one said I’m nuts and full of it.

OK! Whatever…. I don’t care… but I’ll take the forums best guess…. It’s most likely better than mine!
LMAO!
Rumble, in my humble opinion, that is a solid 400+ horsepower combo.
Lots of compression, nice cam with good lift, really good cylinder heads, great intake, proper size carb.
If its not detonating, and has proper timing and fuel, that's an easy 400hp. Good if not great cylinder heads make the difference.
Care for a comparison? My 440 has less cam, less compression, way WAY worse cylinder heads, a little more top end intake, and an 850 (appropriate for its size).
It makes an honest 500 at the crank. Everything you have should make more hp/cu in.
 
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Thanks Gent’s. IF I ever get to dyno this engine (not happening) I’d hope for better than 360 hp. But IDK.
I took it to the track @ Orlando w/mderoy to dial in the car some. With 3.55’s on 26” tires and a tight converter I wasn’t expecting much. The best trap was 101 with a OE shifter that gave up the ghost after the first run. First run it fell on its face since the carb was a OOTB Summit 750. (AKA Holley 4010) Mike gave the carb pump shot a quick twist and said try that! It worked but the shifter would not go into first. I also never let the tire pressure down from the street driven 35psi. It was terribly slow but still fun. Just stab and run from idle.

I know there’s lots left in it but I have not been able to get into the track yet. Just do remember it’s a street driven car designed for easy driving and not racing the track.


You are in Florida. You should be able to swing a dead cat and hit an engine dyno.

If you’ve never been to the dyno you ought to do it once. Of course, once you do it you’ll be hooked. If the dyno is run correctly you can learn a ton in a relatively short time and for pretty cheap money.
 
Rumble, in my humble opinion, that is a solid 400+ horsepower combo.
Lots of compression, nice cam with good lift, really good cylinder heads, great intake, proper size carb.
If its not detonating, and has proper timing and fuel, that's an easy 400hp. Good if not great cylinder heads make the difference.
Care for a comparison? My 440 has less cam, less compression, way WAY worse cylinder heads, a little more top end intake, and an 850 (appropriate for its size).
It makes an honest 500 at the crank. Everything you have should make more hp/cu in.
Thanks. I have always said and here is proof, get the best cylinder head you can and since the wife was in the market for cylinder heads, she went and bought them. Spoke to B3 and she bought the PRW 1.6’s from him.

I figure, no matter the combo, if your cylinder heads are the one and only thing your going to spend money on, that’s the part hands down the best to get as bitchen as you can.

You are in Florida. You should be able to swing a dead cat and hit an engine dyno.

If you’ve never been to the dyno you ought to do it once. Of course, once you do it you’ll be hooked. If the dyno is run correctly you can learn a ton in a relatively short time and for pretty cheap money.

You sir are most correct! I have never been to a dyno.
I have found several places very close to me in the Melbourne area that have dyno’s. I would love to get a mill on one and YES! I am sure I’ll be hooked.
Well before engine masters came out in TV, I thought about my future retirement and just doing engines for fun.
 
1969 Dart
Built 318
3:55 suregrip
904/2800 stall
235/60/15 Drag Radials
50 mph/2000 rpm
 
1969 Dart
Built 318
904/2800 stall
3:55 SG
235/60/15 Drag Radials 26" tall
50 mph @ 2000 rpm
 
I like 3:23 for all around cruising. I swapped to 3:55 in my 499" in GTS but will probably swap back to 3:23, Joe
Personally I would consider the 3.23 year to keep highway RPM down. 3.55 is pretty reasonable and is a quiet gear. This will also work well with an OD trans, especially if it has a lower first gear.
The mentioned 4.56 is a bit low for a street car even with OD. Real fun when you jab the loud pedal to the radiator though.
 
I run a 2.7 gear ratio on my 4-speed 69 barracuda with a 426 SB stroker and 255 street/strip nitto tires mounted on 17 inch wheels. Currently there is no wheel spin on good traction pavement and it launches strong, at high speeds (120-140km/hr) the engine revs stay around 3k RPM. Good overall compromise I think. Even on 4th gear you slam the pedal and can leave behind modern "fast" vehicles. Have considered on maybe changing to a 3.0 ratio, but would not go higher than that, at least on my application.

Prior to the current axle I had a 3.55 ratio and driving at normal highway speeds was very annoying, RPMs were 4k and above, plenty of wheelspin when slamming the pedal on the first three gears. I had BF goodrich tires back then as well, so not the best traction rubber.
 
I currently have a modified A999 behind a 360 with 10.2 compression.
For now I'm using a 8.25 rear with 3.21 gears.
I go about 3000 rpm's at 73 mph (27 inch tires) I've gotten up to 17+ mpg's going to my in-laws in Louisville CO. (500+ miles) while keeping it at those speeds.
I know your 904 has different 1st & 2nd gears so a 3.55 might be a good if you want a decent all around gear. I don't know how much highway driving you do or want.
I do plan on getting OD eventually, but first things first I need to finish my 408 and my 8.75 489 rear which are still in pieces.
with the OD planning in mind, I'm still trying to decide between a 3.55 or 3.73.
 
Thanks for all of the opinions and thoughts. I learn plenty from the off topic gassbagging so I’m certainly not going to complain.
 
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