Jump to content

Recommended Posts

post-103816-0-91319500-1464929475_thumb.jpgHello other z nuts.

I have a 1977 260z 2+2 which, after some work, has now been my daily driver a while.

I am not keeping it stock but am making it more comfortable, reliable, economical etc a bit at a time.


I've been driving it every day for nearly two years and have scored a rebuilt RB30 out of an R31 to go into it, along with both a manual box and a Jatco auto including computers for each. It is currently running a HM reconditioned (some time prior to 1992) L26 with twin SU's and a five speed manual and a 3.545.


Before I ask let me say that I've been trawling the forums for some time and have found brief references to the following but nothing definitive or from someone who has actually done it so that's why I'm asking here - hopefully one of you has been as strange as me or worse.



1. Will the yoke off a stock 260z tailshaft fit either a manual (5 speed) or auto (4 speed jatco) box out of an r31


2. Am I likely to face length issues. e.g. will i need to have the tailshaft cut and pasted?


3. If I need the yoke off the R31 tailshaft is it likely to fit the 260z shaft or is there too big a difference in uni sizes?


4. I scored a Castlemaine Rod Shop set of engine mounts and there's this weird wishbone thing which others seem to say is for the transmission. Can anyone please explain it cause it seems unnecessary at this point - or is there a massive difference in the weight or fitment between gearboxes which the stock mounts wont cope with or cannot be adapted to fit?


5. I have the chance to fit a single downdraft intake manifold off an old GQ RB30 - has anyone run an RB30 Carby in a Z and had good results or is EFI always superior?


6. Am I likely to damage my R200 or the stock tailshaft by putting an NA RB30 in front of it?


7. Am I likely to have shifter placement issues with either the Manual or Auto on the RB30?


8. Will I need to change the shape of my trans tunnel to fit the gearbox, or to add holes to the firewall to have access to bell housing bolts?


9. If you or anyone you know has done this mod and thinks there's other stuff I may have missed (I know about the sump and pickup mods needed) please chip in.





Share this post

Link to post
Share on other sites

I'm using a mobile, so this'll be brief:


1. Yes your Z tailshaft yoke will fit either R31 transmission.


2. The Z tailshaft will fit without needing to change its length.


3. See above.


4. Your Z Cross member wont fit the r31 gearbox as it's mounting face is 50mm further rearwards. Hence the fabricated CRS cross member.


5. Stick with the EFi.


6. No, those components are more than up to the task.


7. No. Same position.


8. No. The r31 gearbox does not require any extra room.


9. Sump & pickup are in the wrong place, so you'll either have to flip the bowl in the sump rearwards & mod the pickup to OR find a 200ZR sump & pickup (getting rare & expensive).


At the end of the day, you need to ask yourself if you want to do all this work for only a small gain in hp & trq, and a marginal gain in economy.


IMHO, change your diff ratio to a 3.9 & enjoy the better acceleration it provides.

You'll probably get better economy too...

Edited by Lurch ™

Share this post

Link to post
Share on other sites

Cheers very much for the info Lurch. I appreciate that swapping in a stock RB30 would not be vastly superior to a fresh L26.

I'm doing the swap because the L26 is very tired and the money I would have to throw at it to either do a 3.1 or even just a good reco would give much better bang for buck on an RB.

The RB is recently reco'd (less than 5K)

I also have access to an RB25 head.


My Z has been through the wars a bit with damage and old repairs on all four corners as well as a non original bonnet which was previously red and previous to that green, as well as non original headlight surrounds etc.


I saved it from becoming a parts donor for another Z and the engine is also not it's original - which is also why I'm not precious about modernizing some parts. 


I did see a link a while ago in Japanese I think where someone had modded an RB25 or 26 head onto an L26? That would be fun to drive but a nightmare to work on I imagine.

Share this post

Link to post
Share on other sites



I understand the desire to move to an RB powerplant, there is a lot to be said for modern EFI etc.


However do not underestimate the true cost of fitting and getting engineering approval for the swap.

You could get a lot of L series magic for the same money.


Just my 2 cents worth.





Edited by PB260Z

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now