3800 converter too much ?

[44070dart]

Thinking of buying a '73 Duster 360/380 crate, 3:70 rear gear, built 904 with a 3800 stall ..
Going to see it next week. The 3800 has me concerned. I sort of understand how the converters work, my concern is streetablity of this high stall. This is a street car for me, maybe a run down the track, but mostly street driven. I like to drive them so it will get used to cruise around. I've looked at video and looked at different site for some answers, but the guys that respond seem to be racers who run 4500 converters on the street. My question, is 3800 to much for a street car with limited track time.

 

[Mtrhead]

Borderline

 

[Rat Bastid]

It will be fine. I have guys running converters that are 5300-5500 on the street, and as of yet they haven’t seen the strip. Drive it. And when you drive it leave your preconceived bias at the curb. I’m not saying that to offend you, I’m saying that because that bias can sway your thinking without giving something a fair chance. I would ask what brand of converter it is. Just so you know.

 

[12many]

It depends on the quality and if it’s considered tight or loose. Do you know if it has an auxiliary trans fluid cooler? Only way to know if it’s fine or too much (to you as it is very subjective as to what is acceptable or too much based on personal preferences etc) is to test drive it in varying scenarios. What you’re concerned with is how much heat, how hot the trans will be driving around from it possibly being a looser 3800 stall. It’ll still move from idle on up the rpm’s but it’ll generate more heat being that it’s loose. If it’s a tight style 3800 I wouldn’t worry. If it’s a quality converter you likely wouldn’t even know it is a 3800 until you flash it, or floor it from an idle when stopped. Test drive it, or have the seller take you for a spin. And have him demonstrate around town stop and go along with at stop, slow roll wot runs.

 

[Dana67Dart]

I think so BUT I always get shot down by the racers out there. (Fire away!)

at least it is not a terrible difficult thing to change if you want to down the road.

 

[abodyjoe]

Thinking of buying a '73 Duster 360/380 crate, 3:70 rear gear, built 904 with a 3800 stall ..
Going to see it next week. The 3800 has me concerned. I sort of understand how the converters work, my concern is streetablity of this high stall. This is a street car for me, maybe a run down the track, but mostly street driven. I like to drive them so it will get used to cruise around. I've looked at video and looked at different site for some answers, but the guys that respond seem to be racers who run 4500 converters on the street. My question, is 3800 to much for a street car with limited track time.

depends on the converter. if its some 30 year old crap then yes too much. if its a good (not that cheap **** on the market) modern say 9.5" then as long as the guy who ordered it was 100% honest about the combo and intended use it should be fine. these good modern converters are incredible.. can drive around all day and it feels almost like a stock converter, mash the pedal down and its like you were shot out of a freaking cannon..

 

[12many]

I think so BUT I always get shot down by the racers out there. (Fire away!)

Personal preferences, no incorrect answer. I like manual steering, brakes, window cranks, locks, loud exhaust, no stereo as I want to hear the engine....



although I’m not much for fumes!!!

 

[44070dart]

Yeah I need to drive to see, but I was wondering if other non-racing types use them. I figured it would generate heat and it does have a extra trans cooler. The combo is new so I'll check with him to see the brand and size. I do some highway driving and was thinking this thing is slipping until 3800 ?? .. is that the case

 

[Rat Bastid]

Yeah I need to drive to see, but I was wondering if other non-racing types use them. I figured it would generate heat and it does have a extra trans cooler. The combo is new so I'll check with him to see the brand and size. I do some highway driving and was thinking this thing is slipping until 3800 ?? .. is that the case

They don’t slip to 3800. The good ones don’t anyway. That 3800 is the flash stall speed so you have to hit the converter will all torque you can make to get it to flash that high. Where you will make loads of heat is cruising through town in 3rd gear (drive) and the rpm is low for your road speed. At that point you’ll be slipping the converter and making heat. At that point, grab the shift handle and put it in 2nd. That will raise your rpm enough to get it above slipping. I prefer to shift everything so I use manual valve bodies or at least a shift kit that makes it manual shift. You can use kick down linkage and let the transmission shift on its own with a converter like that. It just depends on what you like.

 

[K.O. SWINGER]

If your car is a toy I say go for it, if it's a daily driver probably too much converter in my opinion you're getting into the realm of race converters at that point but if that is your goal then go for it. To me it's sort of like running 430 or 456 gears on the street can you do it absolutely is it a good fit for traffic and other situations you will encounter in normal driving? Not so much.

 

[abodyjoe]

I do some highway driving and was thinking this thing is slipping until 3800 ?? .. is that the case

again it depends on the converter. the cheap **** or 30 year old crap then yes it may slip and create heat. a good modern converter spec'd correctly for the car, combo and intended use it will be fine and act like a stock converter on the street... when dynamic built my first 9.5" converter they said it was going to flash to 3800.. i said are you nuts? lol.. he assured me that it will be just what i wanted.. boy was he right... that was a mp short block, eddy heads 508 cam, 904 and 3.91 gear...
our current dart has a little more mild 360 in it (higher compression and bigger cam then stock) but i still had a 9.5" converter built for it.. this one is a 360,904 and 3.23 gears... i told them it was going to be 99% street driving. may see the track once every few years.. the receipt even says customer wants the converter tight.. runs awesome ion the car.. no extra trans cooler on it. only uses the stock radiator cooler and we drive it all over the place, around town, stop and go traffic, 3 hours on the highway..etc.. when i ordered my converters i was 100% honest about the cars combination and just as important the intended use of the vehicle.. if you aren't honest with those two things when ordering chances are you won't be happy... so again it really depends on the converter and who ordered it.


why are you even looking at this car. seems so far away from what you want. you sound like you would be happier with basically stock 360 and 3.23 gears..




.

 

[Ottmundr]

It will be fine. I have guys running converters that are 5300-5500 on the street, and as of yet they haven’t seen the strip. Drive it. And when you drive it leave your preconceived bias at the curb. I’m not saying that to offend you, I’m saying that because that bias can sway your thinking without giving something a fair chance. I would ask what brand of converter it is. Just so you know.

Agreed, leave those pre-conceived bias-ply polyglass tires at the curb.

 

[44070dart]

" why are you even looking at this car. seems so far away from what you want. you sound like you would be happier with basically stock 360 and 3.23 gears."

I have a '68 Charger 383 2 bbl / auto and that drive train is fine with me because of the car it's in, and I can cruise around all day.. I have had muscle cars forever and just sold a '66 427/ 5 speed Biscayne, so I'm pretty familiar with quick cars. I just don't want a race car for the street, and thought this car would be great, but the high stall converter concerned me as I'm not use to them. Driving it will give me some answers, but wanted to ask non race guys that have lived with them for a while.

 

[abodyjoe]

find out if the owner knows whats in it.

 

[Rat Bastid]

The biggest problem is how one defines a “race” car. By my definition, what you are looking at is far from a race car. To that end, one may ask how do I tell the difference between a race car and a street car? The short answer is there is no definition, but I know a race car when I see it. And it’s only you who can determine what a race car is by your definition. What you see as a race car I see as maybe a day 2 car. Maybe. And that’s why there is all the confusion. By further explanation, I say that the definition of a street car is pretty narrow. And the definition of a race car is pretty narrow. That leaves a gigantic middle are where both are blended. That big middle area is what defines what you think you have or want. You have to be honest with you about what you want. Otherwise, you build or buy something you hate. Just my opinion on how these definitions get sideways and cause confusion.

 

[44070dart]

Sometimes I think the difference is someone over 55 opinion of a street car and a guy in his 20's I'll get to drive it next week and get info on the converter, we'll see then.

 

[CudaFactHackJob]

What's the big deal? If you don't like it then just change it. I don't understand how this could be a deal breaker.

 

[33IMP]

If it truly has a 3.73 gear, and maybe a cam that needs a loose converter to idle in gear, I wouldn't worry about the converter. 2.76 or 2.94, or even 3.23, I would say no, too much.
(This from a guy with a 5500 and a brake behind a 408 in a light, street driven car, with 4.57s)
Edit: 3.70? gear? What rear? 8 1/4, 8 3/4, or something else?( 9"?)

 

[fishmens67]

To me a vintage Mopar street car is anything with 4.30 or higher rear axle ratio.

 

[1969383S]

I have one "3800". It has tightened up over the years though.

They always do! When first installed 4.56 rear and today 3.55! Still a bit loose but not at all like when freshly built! 8.5 inch custom unit!

It has survived Heavy strip and street!

 

[RustyRatRod]

It will be fine. I have guys running converters that are 5300-5500 on the street, and as of yet they haven’t seen the strip. Drive it. And when you drive it leave your preconceived bias at the curb. I’m not saying that to offend you, I’m saying that because that bias can sway your thinking without giving something a fair chance. I would ask what brand of converter it is. Just so you know.

This ^^^^^^^

This ain't the 1970s anymore. You can have a 5000 stall and drive it around on the street just fine. I agree too about asking what brand converter.

For a hot street car, I consider 3500-4200 a starting point. Much less than that and you get into stock stall territory.

 

[RustyRatRod]

The biggest problem is how one defines a “race” car. By my definition, what you are looking at is far from a race car. To that end, one may ask how do I tell the difference between a race car and a street car? The short answer is there is no definition, but I know a race car when I see it. And it’s only you who can determine what a race car is by your definition. What you see as a race car I see as maybe a day 2 car. Maybe. And that’s why there is all the confusion. By further explanation, I say that the definition of a street car is pretty narrow. And the definition of a race car is pretty narrow. That leaves a gigantic middle are where both are blended. That big middle area is what defines what you think you have or want. You have to be honest with you about what you want. Otherwise, you build or buy something you hate. Just my opinion on how these definitions get sideways and cause confusion.

If one cannot tell the difference between a street car and race car, they need to take up tiddly winks instead.

 

[12many]

If one cannot tell the difference between a street car and race car, they need to take up tiddly winks instead.

If it’s got a roll bar or cage, an 8” converter if auto , 4.xx and up gears, single plane intake, big *** carb, 260+.050” duration it’s a race car being run on the street. Yup it’s a street car

 

[33IMP]

Let's see.....
Roll cage, check.
8" converter, check.
Transbrake, check.
4.57 gears in a nine inch, check
Victor intake, check.
850 dp, check.
265° solid roller, check.
2" small block header, 3 1/2 exhaust, check.
That's my street (driven race) car.
P.S. there are lots more radical and fast than mine.

 

[AJ/FormS]

Thinking of buying a '73 Duster 360/380 crate, 3:70 rear gear, built 904 with a 3800 stall

Since it's all ready installed, just drive it;
that 380 crate engine is pretty tame, and the 3.70s are an in-between gear, so it'll be fine..
====================
Is it what I would build? No. But so what. You have the perfect opportunity here to find out what you do or do not like, and swapping convertors at a later date, is relatively painless.
The thing is this; in First gear, with street tires and no traction aid, that
380/3800/3.73 combo will spin the tires at WOT, all the way to shift rpm........... but it will probably do that with a 2800 as well.
Where the 3800 will earn it's keep is in second gear, at a roadspeed that would stall the 2800...... like say 38 mph.
Cruising in Second with 3.73s and 27s, might get you 2600 at zero slip. If you nail the gas with a 2800 she might flash to say 2900, and the engine is way off the cam, so to get into "Rapid Transit", you would need to downshift.
But with the 3800, she might flash to over 3800, no matter, and that puts your crate-engine right around peak torque. If you downshift into first at 38mph, the rpm will flash to maybe 5000...... and the tires will spin up, driving the rpm to well past the power peak and you will want to shift right back into Second. This is where the 3800 earns it's keep; Not on the starting line; unless you can figure out how to keep the tires from spinning.
The other thing is 38 mph with 3.55s,lol . In second gear, this is 2450@ zero slip. perfect for cruising around and sneaking up on Chevies. A quick downshift gets you 4100@ zero slip, say 4700 coupled, and ready to rock. Your roadgear will be 3.55 x 2.45=8.70. Whereas with 3.73s it will be 3.73 x 1.45=5.41

with the crate engine, the torque;
at 38mph/3.55s in First @4100 might be 440ftlbs, whereas
at 38mph/3.73s in Second @2900 might be 403ftlbs
Sounds not bad right?
Except with the above roadgears ;
the 3.55s get you 8.7 x 440=3828 ftlbs, whereas
the 3.73s get you 5.51 x 403=2221
Here is a case of less actually being more.
On the street TM (Torque Multiplication is King.)
But hang on;
I picked 38 mph for a reason, it illustrates my point. The advantage to 3.55s is not across the board at all roadspeeds. It only favors 3.55s, when the 3.73s are in the next higher gear. The advantage that 3.55s have will only be , until you gotta grab Second, then the advantage will go to 3.73s. However, that stinking 380 makes decent power all the way to 6000, which with 3.55s and 27s comes to ..... about 50mph in First gear.
AND
you can give the advantage back to the 3.73s with more stall. So, IMO, someone has given your combo some serious thought.


Dyno Results/Superflow 901/Tested at Westech
Mopar Performance 360 cid 380 hp rated

RPM TQ HP
2500 380.6 181
3000 402.9 230
3500 415.1 277
4000 437.8 333
4100 439.5 343
4500 437.1 375
5000 416.3 396
5400 398.6 409
5500 388.6 407
6000 343.9 395