4 speed comound tranny for a five speed transmission

Hi everyone:
I have a chevy c10 69 with a 350 engine and four speed manual transmission but I want to know if is possible upgrade it with a newest 5 speed manual.
Can you tell me if there are 5 speed trannys for full size trucks (silverado,cheyene,gmc)I know minitrucks have 5 speed but I don´t.
Can you please give ideas, I wouldn´t like make the
converssion to automatic.I know would be more confortable.
   

Classic Chevy 5-Speed has a conversion kit (the tech story is on here somewhere. Google Classic Chevy 5-Speed  Custom Classic Trucks)if you want to use new parts. With a little research you can figure out how to adapt junkyard parts if price is a problem. Either way you won't believe how much better your truck will perform.  

The best source is to look in junkyards for a wide ratio 5 or 6 speed manual transmission out of a truck that has an engine with at least as much torque as yours. If you get one out of a truck that has a small block Chevy, then you know where to get a bellhousing, etc that will bolt right up (your present bellhousing might not work).

I don't recommend using a transmission that has an overdrive as its highest gear. The overdrive has at least a 6% power loss, compared with a direct drive high gear which has less than 1% power loss in high gear. If performance is important, then your top speed is affected by this. If mileage is important, tehn this is the difference between getting 20 miles per gallon with an overdrive and 21 with a direct drive transmission, assuming that you use an axle ratio to give the same overall final drive ratio in both cases. In other words using a 4.0 axle and a .7 overdrive will give 20 miles per gallon and where a transmission with a direct drive high gear with a 2.8 axle will give 21.

To make this work on the other end of the scale (low gear) you have to have the same overall reduction in first gear as you had with your 4 speed. Using the example above a 4 speed with 3.00 reduction in first combined with a 4.00 axle ratio gives 12.00 in low gear. With a 2.8 axle ratio a 5 speed would need to have a low gear of at least 4.28 to give the same performance in low gear.

The best way to proceed is to find out your present axle ratio, teh ration in each of your 4 speed (most probably direct drive if it was built in 1969) and multiply out the overall final drive ratio in each gear.

Look at your tire size and determine which axle ratio would allow you to cruise at torque peak in direct drive at highway speeds. Pick the axle ratio, and tehn look for a 5 speed wit the right ratios to give the performance you need in low gear (and not burn that clutch up).

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