Grrrr...torque converter options options and various rantings and ravings...

[flyinbrick68]

I'm trying to sort out my combo for the converter and the cam for the stroker for the fury... I've got it down to two cams and I'll probably go with the smaller camshaft that's rated 225@.050 duration .510 is lift. The larger being a 232@.050 duration .525is lift. I've had about ten different answers from ten different trans guys anything about converters. Maybe i'm asking to much from the build? I was told with a 28.8" tire which is the 235/75r15's on it that a stall converter with a set of 3.23 gears would just burn up a 727 trans cruising at 60mph ect. I know its not a small tire but its on a 15" rim for Christ's sake. I've had suggestions anywhere from a 2000 stall 12" converter with the 3.23's to a 9 1/2 3400 stall with the swapping to the 3.91's at the track. I'm trying to figure out how to have my cake and eat it too. It'll be a weekend only fun car yet I want to be able to cruise it down the road occasionally without running much over 3000 rpm. Plus i'd like to get it to the track a few times a year for kicks which is when the 3.91's will come in handy. I'll admit that it gets old after a while hearing a motor scream at over 3400 rpm going down the road at 70 plus. It's what I put up with in my 68 d100 with in the slow churning ow compression rv 440 at the moment. Love the acceleration hate the short term cruise factor on long trips. An overdrive with the 3.91's would solve my problem but its not in the cards or the funds so here's my dilemma. I'm stuck with a decision between a short cruise, brutal pavement pounder with the 3.91's and a higher stall which makes the kid im scream yippiee!!:busted:.

Or a leisurely long cruise low stall 3.23 geared all show no go fury which make the enjoy the slow relaxed side of life of me say yup, that'll do. ccasion14:
Choices, choices... It's about enough to drive a guy insane and make him rip out his hair. Oh if only the guy off of craigslist had been honest about the car the motor hadn't have blown and I could just enjoy it in stock form!!! GGGRRRRRrrrrrrrrrrrrrrrrrr.

 

[Badvert65]

Only reason I would vary from the stock converter would be the cam choice. With the more radical cam, you would chose a higher stall. With a higher stall, you might want lower gears (higher numerically).
I have a 3000 stall and have been running 3.91 gears on the street with 15 inch rims (p275 50-r15 tires) and haven't had any problems. (This setup has been in the car since around 1985.)
I originally had the Mopar "509" cam and it was great. I later put a 'milder' cam in and left the gear/converter setup alone. Never had any grief. I'll keep the same trans/converter in it when I switch to my stroker-supercharged engine later this year. I may switch to 3.55 gears but I am not really certain of that just yet.

 

[Badvert65]

With your combo, I would run anywhere from a 2600 to 3200 stall converter just to make the engine easier to tune with that big cam. You shouldn't have much grief cruising at 60 mph with the 3.23 gears. those gears might not be best for your acceleration if the engine (cam) doesn't come in until 2500+ rpm, but it should be streetable.
A big cam engine w/ stock converter is just not as easy to 'street' tune as one with a higher stall converter (in my experience). Your gear choice should just be to help the car accelerate inside of the engine's power band (torque).
Again, just my two cents worth.

 

[flyinbrick68]

Thank you very much for the details and the response. I'm trying to get ahold of my cam grinder to hammer out some of the details so I can get that narrowed down then ill decide on what set of gears to run from there. I was kinda thinking something around 2800 but the guy from ati I guess thought id be better off with a 2400 stall. well see I guess. either way I don't think ill be too disappointed. I live in Nebraska and the majority of the roads are 65 and interstate is 75 doubt I'll be taking many long trips that way though some day id love to make it to carlisle.

 

[tdenkler]

Gee. Thats why i like 4 speeds!

 

[flyinbrick68]

If I had the budget to put a modern 5spd in my fury id do it in a heartbeat lol. But decided i'd better be conservative and listen to people who know much more than I do. I'm going with the 225 duration cam most likely which sound very similar to an engle k56. Probably end up with a 10" converter with a 2400 to 2800 stall from ati. I think id prefer it at 2800 but that's me, and I'm not an expert so i'll let them do the deciding.

 

[commando1]

2800 will be the best compromise.
There never will be the perfect compromise.

 

[flyinbrick68]

All else being perfect with 3.91 gears it ought to be able to get up to a decent speed. If my heads flow well enough should be good for a sub 13 second quarter. I'll be happy with that and compromise

 

[Badvert65]

Running in the thirteens is almost a given (depending on traction). I went a 1/4 mile best, 12.35 @ 108 with the bigger cam (440) in my 65 fury (single carb too).

 

[bajajoaquin]

I don't think that 225 degrees is that big a cam. 230-odd is starting to get up there a bit, in my opinion. I had a small-block with 246 degrees of duration, and it was really fun when it came on the cam, but it was too much, and in all reality slower than a smaller cam would have been.

Which isn't your question.

At 70 mph, you're going to be turning about 2900 rpm with 3.23 gears and about 3500 with 3.91s. On the flip side, if you run 3.23s, at 70 mph, you can still have it kick down to second gear, which would be 4200 rpm. That doesn't address your concern about running at the track, but it might ease your mind about being over-cammed on the street.

These numbers were calculated with 235/75R15s, and assuming 5% torque converter slip and a rolling diameter of 27.4 inches.

Looking at it another way, what if you just got a second set of wheels with tires better suited for the track? 245/60R15 has a rolling diameter of 25.2" which brings your revs up to 3200 at 70mph, a change of 10%. For comparison, the difference between 3.23 and 3.91 is 17.5%. So you get more than half way to the gearing difference with a tire change. BFG makes a drag radial in 235/60R15 which gets you a few more RPM.

You could run white walls on the street, and get something stickier for the track. You would hook up better, and have lower gears, for a lot less money than an overdrive.

So I'd go for the smaller cam, a torque converter on the smaller end of the range (2200-2400) and get a second set of wheels and tires.

 

[flyinbrick68]

That's why I love this site, so many people with different points of views and different ways to look at a situation thank you for the insight. I did overestimate the weight of the fury though. I was thinking it weighs in at around 4200lbs. and everything I've found so far say's it should weigh in at around 3800. That is a hell of a difference and I might just mention that to the cam grinder. If nothing else it might be amusing to him and it may change the way the tq manufacturer looks at the stall on the converter also. Doubtful but hey you never know its worth a shot. I'm not real fond of the stock steelies that are on it really but they'll do for now. Thank you!

 

[bajajoaquin]

3800! That's 400lb less than a new Dodge Nitro. I mean, my car is a huge boat, but it's fun to remember that these cars are heavy compared to '60s VWs and '70s Toyotas, but modern cars are heavy.

A quick search shows a new Camaro at between 3800 and 4100 pounds. A Honda Accord weighs about the same as your car.

 

[70bigblockdodge]

Neither cam is big, I have a Hughes lumpy idle muscle car cam, it has approx. same as the smaller of the two you have listed but ground advanced by 3 degrees and my keyway is off by 2 retarded which made it a wash cam idles good and has 13" of vacuum in drive and that's in a 383. Remember lift is free except for valve spring and guide wear. Duration is what gives quality or poor drivability also if a mopar cam doesn't have 85% of duration at .050 compared with advertised it is a chevy regrind or slow ramps not the end of the world just something to keep in mind. Converter needs to be below your expected highway rpm or else you will need like two trans coolers or a really big one to dump the heat using the 70 mph and 2900 rpm you should be fine with a 2800. bajajoaquin's points are good reduce the tire dia to effectively lower gear ratio.

 

[Badvert65]

FYI, I had my 65 Fury convertible weighed at the track. 4190 lbs, steel wheels, no spare, 1/2 tank of gas. Body all steel, no driver. This was basically stock. complete with heater and radio, 440 automatic, power steering, manual disc brakes.

 

[65sporty]

I think you may be happier with the smaller cam and a stall around 2500, but the more torque you make the higher it will stall. the same converter behind a high winding small block will stall at a different speed then behind a high torque big block.

 

[flyinbrick68]

Yeah Im going to go with the smaller cam and I wont even have to use roller rockers if I don't want the lift if reasonable. My heads are prepped for larger lift so if i wanted I could swallow the .544 id get with 1.6 rockers. If i stay with the 3.23's for cruising and a 26" or 27" tire I could manage a 2600 stall crunching the numbers. For the track swapping the gears and theoretically if I had the grunt I could almost run a 12.40! That my friends is exciting!:car flipper:

 

[70bigblockdodge]

I think that a good combo and if runs mid thirteens with 323 that's bad ***.

 

[flyinbrick68]

I'm optimistic, learning and may make mistakes, but im going to enjoy driving the hell out of this car when I get it going. I'll put in the 3.91's for the track if I get the chance to hit it up so I can take full advantage of the cam. I don't see much of a difference using that virtual engines software from plugging in the numbers between the cams. Decided id better keep the torque down low rather than gain an odd 10 hp or so in the upper rpms by going with the bigger cam. I do plan on strapping the car to a dyno to get it dialed in later on. If I had that cash id compare both cams itd be interesting.

 

[flyinbrick68]

Now to hunt down a set of 8" rims get my measurements for the backspacing ill need figure out what axle I can run and get the rest of the parts for the motor gathered up.

 

[moper]

What size is the engine? B or RB based stroker? What heads are you running? I've got 505s, 496s, 470s, and 451s running around and IMO neither of those cams would be great in anything bigger than a 3.75 stroke. In terms of what might work best - run a convertor that will be at it's stall speed or above at your cruise rpm for 50mph. That should be around 1900rpm. So lower is better. The "en vogue" deals are 9.5 inch "tight" units that will be tight at lower rpm, but will flash higher when needed. But - the heavier the car the harder it is to get it properly matched. Your car's heavy. I would go with a 10" custom from PTC or Ultimate Convertors that is rated at 2200 brake stall behind the engine you're building. And you should have chosen the camshaft well before talking to the convertor guy. When you want to race, swap gears. A convertor that runs good with 3.23s will still work decent with 3.91s. But a convertor that works well with 3.91s will feel sluggish and may run hot with 3.23s.