Trans swap

['69 2 door]

Greetings. What is the best 5 speed to swap into my 510? I am running an L20b. Thank you.

[datzenmike]

It's usual to introduce yourself and bring us up to speed on yourself and your Datsun. Pictures are most welcome.

 

Your question is somewhat like asking what's the best length of a piece of string. More info, again, would help. How will you be using your 510? Full race?  Weekend runs? Daily driver? (has to be low maintenance and reliable) if so, in town or mostly on highway? because 5th is only an over drive gear for highway cruising and won't be any faster than a 4 speed in town or the highway. Have you swapped a transmission before or just seen it on You Tube? Do you have tools and a safe place to work on it? Some modifications to the car and some fabricating may be required. Do you have money to pay for the work or doing it yourself?

 

There are at least four L series 5 speeds out there besides the Nismo competition boxes. Here goes for the most common....

 

Easiest... the FS5W63A 5 speed from a first gen 200sx.  As close to 'drop in' as there is. Exact same 1 to 4 gears as your 510 but with a 0.854 over drive. Same length so no drive shaft shortening, speedo on same side, in and out splines the same, shifter location the same, was used with the L20B so is adequately strong enough. May need trans mount mods. Has unique reverse above first gear and takes some getting used to. Not that common, few made and well used.

 

Stronger... the FS5W71B 5 speed that was introduced in '77 from the 620 truck, '80 720 truck,  810/Maxima, 280z and 280zx. Will fit the trans tunnel and bolt to your L20B but that's about it. Comes in wide, mid and close ratio gear sets and several over drive ratios. Designed for the L series six cylinder and used on trucks, very tough. Needs drive shaft shortening and balance,  it's almost 6" longer and speedo on other side so may need a longer speedo cable, transmission mount mods for sure, shifter is slightly to the rear of your 510's 4 speed. Very common, lots of trucks and cars had them. Four speed shift pattern with extra over drive far right at up