Porsche 356

[Mark Sabbann]

Would you consider a "Tall 4th Gear' as long as your transmission needs to be rebuilt?

Mine is a little winny and I'm considering getting a taller gear when it come time to rebuild the transmission. Does anyone have an RPM plot for it? And does a 65C have enough torque that I wouldn't have to switch to a very high revving 3rd gear to get up a slight hill?

My red C (Ruby) has a tall 4th gear. For longer distances and open road driving it's great but for more 'technical' driving on hilly and winding roads, I end up shifting back into 3rd more often than I like in those conditions. So, like a racer might change gearing for a specific track, the gearing that works best depends on the course/road at hand. I don't know the true final gear ratio or if there is more than one 'tall 4th gear' available, but at typical highway speeds I see roughly a 500 rpm reduction over the stock gearing I had in my previous C. When I drove Ruby back to MN from Wayne Baker's shop, he told me that the engine was happiest at 3500 rpm under load and to make sure I was at that rpm when tackling some of the long uphills in SE California, i.e. I-8. That put me at close to 80 mph. I was flyin' but Ruby was happy and running strong!

[DonCichocki]

My "C" came with BBBD gears in the trans. While I had it apart for a new 2nd gear syncro I changed 4th gear to a C 4th gear set, which is only 1 tooth taller gearing, it dropped the rpm's while in 4th gear by about 180 rpm. At the time my car had the stock "C" cam and a 1720cc kit and it pulled it fine, I would not go back. It also made the shift from 3rd to 4th more in line with the rpm drop in the 1st 3 gears, if that makes sense. Look in the workshop manual and check out the graphs for rpm in each gear and you'll see what I mean.

[Roger Shapiro]

Dick, My SC, 1720cc, WR58 cam, has had a tall 4th for a number of years. I’ve travelled from Banff to Boerne TX. Love that gear. Living in CO (5k ft) has not really been a problem. 3rd gear around town. Tall 4th on the hiway.
You should have a strong engine, maybe 100hp. At sea level you could probably get by with a 1720cc C.

[Ashley James]

The owners manual shows the effect of the different top gear ratios. It’s not great.

[DonCichocki]

We should clarify what we mean by tall 4th gear. I'm using the Porsche "C" gear set (27:22) where the stock gear set was "D" (27:23). Vic Skirmants has a tall 4th (28:21??) that drops 600rpm at 80mph to 3,600rpm.

[Jim Liberty]

Porsche produced a "Tall" fourth gear, but I believe they are all gone. Try Vic S., I think he has produced them.

That said, I put one in one of my cars with a 125HP motor, and it was a pain in the #*@ around town. Just too high, and needed to be in 3rd. most of the time. If your driving is all freeway, (NOT IN CA.) it is OK.