356 five speed trans

356 Porsche-related discussions and questions.
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Greg Bryan
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Re: 356 five speed trans

#16 Post by Greg Bryan »

I know the dogleg shift was used at least through '69, that is to say, all 912 5-speeds (with the exception of 912E) have the 901 style shift.
I liked the uniqueness of the 901 shift pattern - drove my 68 for 20 years.
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Dave Merz
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Re: 356 five speed trans

#17 Post by Dave Merz »

I've done both conversions and you don't have to chop anything up for either but unless you have deep pockets I'd go with using stock 901 set up out of early 912 or 911 donor car as all Porsche parts.
IMO, dog leg first gear is fine provided you have good syncro, shift tube guide ring, etc. Shouldn't take long to re-learn shifting if that's a concern.

Chuck Allard
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Re: 356 five speed trans

#18 Post by Chuck Allard »

I raced a 356, early 911 and later 911; each with their specific gearbox. On the track, four close ratio gears are desirable in the standard 356 H pattern. The 356 provided this with changes to gear sets
from Porsche that allowed for the use of the first gear position at racing speeds.. Vic has been providing some of these gear sets for years. The early 901 and 911 gearboxes ('65 - '71) have reverse in the same position as reverse on the 356 box and first over to the left and back (below) reverse (some refer to this as a "dogleg" box). Most racers don't use first except to move the car around and get out of the pits. On the track, this box provided the standard H pattern and various close ratio gears were available from Porsche. The 915 gearbox came out in '72 and had first through fourth in the same position as the 356. However fifth was to the right of third and requires a shift motion forward to neutral from fourth, over to the right and then forward again. Reverse on the 915 is below fifth and beside fourth gear (and has a special lock out mechanism - hint). On the track this is a rather risky pattern on an upshift to fifth and is not a standard H pattern for a usable four gears in a race box. One must pay a bit more attention (slow down) when shifting to and from fifth on the 915 box.
All my VWs and 356s had a nice H pattern four speed gearbox and I was easily able to adapt to the 901 box but the 915 pattern really screwed things up. Maybe I'm showing my age, but on the street I really like automatic transmissions and love to shift my own gears on the track.

Bob Murray
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Re: 356 five speed trans

#19 Post by Bob Murray »

Hi Guy's
Thought I would add to this thread as I just went through this
I have a 56 Outlaw with a 150++HP motor. My concern was
the 741 (rebuilt) trans in the Car would not hold up to the added HP. Also I wanted
to run at a lower RPM. I considered the taller 4th but didn't know if it would be a stronger Trans.
I researched the 901 but did not want to change the suspension
and mounts. Having a 66-911 I found the RPM in 5th gear RPM was too close to
the 356 4th not a big enough advantage (for me). I looked at the trans we are discussing
in this thread but could not justify the cost. I also researched the Gene Berg 5 speed
but would have to do some serious surgery to make it fit. I finally contacted Jacques Lefriant and
after our conversations I decided on his Cadrobbi (Sp??) conversion. He can explain it better, but I am very
happy with the result. I sourced another 741 case and sent it to Jacques he did his magic with an 8-31
R/P and stronger guts. While it was out I converted to C disk brakes. Each of the gears run at a lower RPM
less noise and higher MPG. Now @ 80MPH I run 3200 not 4100. I got more then I expected. I could not be happier.
Happy with the price, time frame and build.
He is a true gentleman to work with. ***** 5 stars
THANK YOU JACQUES

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C J Murray
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Re: 356 five speed trans

#20 Post by C J Murray »

Hi Bob. Your trans is the same as mine I think. I have 150-160hp and now have 25k miles on the engine and trans without problems. You made a good choice and you are right about Jacques. I built my own trans but Jacques supplied many of the parts. He is a great guy to do business with.
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Ron LaDow
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Re: 356 five speed trans

#21 Post by Ron LaDow »

Horses for courses.
Probably most of you who live in the Bay Area are familiar with what's known as the Sunday Morning Ride for the bikers. It leaves Tam (Tamalpias) Junction at what time I no longer know, takes Highway 1 over the coast range to the Pacific side, heads north to Point Reyes Station and then the return is your choice.
I found the run before the bikers did; in the late '60s and early '70s, the first Speedster got 'used up', being forever off the torque curve, on that run. Much later, with the RZV500, I rode with them. You can't do that anymore; the bicyclists leave stains on the front of your bike.
In the '70's, my next Speedster got that 901 'box (with a 5:31 R&P); even an average 1720 made that sucker come out of the switchbacks like jack the bear!
Yep, if good 2L engines were available at the time, I might have done otherwise, but...
Ron LaDow
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Vic Skirmants
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Re: 356 five speed trans

#22 Post by Vic Skirmants »

5:31; is that the ratio, or the tooth count?

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Ron LaDow
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Re: 356 five speed trans

#23 Post by Ron LaDow »

Vic Skirmants wrote:5:31; is that the ratio, or the tooth count?
Sorry - tooth count. 6.2:1
Ron LaDow
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Jay Broemmel
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Re: 356 five speed trans

#24 Post by Jay Broemmel »

Silly seems a bit harsh. People can spend their money however they want. My questions would be:
How much faster than 80 mph do you really want to go in a car with lap belts, and no airbags or crumple zones?
How many miles would you have to drive until the fuel savings added up to the cost of the transmission upgrade? My SC will just purr all day long at 4K r.p.m. at 80 miles an hour with a 4D gear. But, I’m half Italian, so maybe a fondness for a higher r.p.ms is in my DNA. :wink: J

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Martin Benade
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Re: 356 five speed trans

#25 Post by Martin Benade »

I would love to have a quieter cruising RPM, but I am not parting with nine thousand dollars plus, or my bad-suspension-geometry swing axles. And I don't think I could stand a huge rpm drop when shifting from third to forth if I changed 4th gear. The Dr got it right already.
Last edited by Martin Benade on Thu Nov 29, 2018 10:14 pm, edited 1 time in total.
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David Jones
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Re: 356 five speed trans

#26 Post by David Jones »

Jay, I have driven most of my life with 3 point belts except when racing and I agree that 80 mph in a car with lap belts is probably tempting fate. That is why I have 3 point inertia reel belts in my 356's and to hell with originality. Of course I stay within the speed limits so my risk factor is already low.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

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Bill Oldham
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Re: 356 five speed trans

#27 Post by Bill Oldham »

Ron, as a cyclist, as well as a 356 owner/driver, I want to ask you to show a bit more respect for us. Think about it, "stains" is kinda disrespectful way to refer to another human being, even if you don't like the way they spend their time. I know its cute, but too many of my friends have actually become "stains".
Bill

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C J Murray
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Re: 356 five speed trans

#28 Post by C J Murray »

Potential fodder for "Mildly Insulting"...
Bill Oldham wrote:"stains" is kinda disrespectful way to refer to another human being
Jay Broemmel wrote:Silly seems a bit harsh
'57 Speedster
'59 Sunroof
'60 Devin D Porsche Race Car
'63 Cabriolet "Norm"
'67 911 S Original Owner
'03 Ferrari 575M
'09 Smart Passion

Dick Weiss
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Re: 356 five speed trans

#29 Post by Dick Weiss »

And--then there's the 7-34; Need one?

Bob Murray
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Re: 356 five speed trans

#30 Post by Bob Murray »

When I acquired my outlaw the 741 trans had been rebuilt. It shifted well and was quite. My concern was how it would
hold up with the higher HP. I didn't want to ruin/blow-up the original trans. I wanted something that I would not have to worry about.
I do have a normal Cab and do enjoy driving it. But remember this is an Outlaw. It is louder :D and quicker :D . For long drives
the normal Cab is perfect. But there are days when you want to just HIT IT :D
I was able to achieve my main goal with Jacques Tranny. It is stronger, Car is quieter, no 4th gear RPM drop and as an added bonus better MPG.
Since it is a 741 Case it slid right in and at a much better $$$$$ Goal Achieved

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