vk 308 transplant into vc 253

[Hoc66]

G'day im just looking for some advice,i have a vc sedan L,its a factory 253 4 speed m20 box 3.08 diff,its got just under 220,000ks,has power steering,cruise control,4 wheel disc brakes and air con (all appear factory fitted) it also has a brock body kit simmons 15x10 and 15x8 on it (have original owners book listing engine number and diff pinion and crown gear numbers etc).....is it worth taking the 253 + plus diff and box out and put in a vk 308 i have sitting in the garage +m21 box + diff (need to buy,from what ive read on here the diff and box may not be strong enough for a 308), and put the 253 etc in the corner of the garage to be able to put back to original motor + running gear back in. Or would it be better to just do the swap and sell the original motor,box and diff,.Is there any value in keeping a base model fairly original although the boat has sailed a bit with body kit and wheels,any help appreciated

 

[Smitty]

.. its non-standard now so another change?
no worries go for it I reckon

oh .. and yes you will need the bigger diff behind the 308

 

[Hoc66]

.. its non-standard now so another change?
no worries go for it I reckon

oh .. and yes you will need the bigger diff behind the 308

No worries smitty,how about the box ? im not going to build a bruiser only going to put new rings and bearings etc in the 308 and just freshen up,i drive the car a lot between where i live and civilization over 100ks return,so id want a diff ratio suitable for highway ks,which i think is well covered on forums here,thanks for your input mate i appreciate it,cheers

 

[Smitty]

No worries smitty,how about the box ? im not going to build a bruiser only going to put new rings and bearings etc in the 308 and just freshen up,i drive the car a lot between where i live and civilization over 100ks return,so id want a diff ratio suitable for highway ks,which i think is well covered on forums here,thanks for your input mate i appreciate it,cheers

Box??...M21 is fine behind the 308.
everyone goes.. they are **** coz I have busted (name your qty) of them. But ....

Properly built with a properly adjusted shifter (and NO drag racing, that is what kills them) they last for years.
I know coz i am running one in my VK race car. Very carefully built (by me) with a few mods to assist it on the
track (mainly oiling and lubrication), I am still running the ORIGINAL gear box that was in the VK when i got it.
Yeah, it has some new gears, cluster and synchros but that box is handling some mumbo (over 220 rwkw)
and even with 140w Competition oil in it, it is sweet on the track

 

[Hoc66]

nah mate no drag racing for me,a v6 would teach the old slug a lesson and the vk motor going in is fairly stock,ill follow your advice and use the m21 ,i dont have the knowledge you have Smitty(seen a few of the tips and mods you helped with on here)...if i was to try and build a gear box it would not be pretty!!and if it can handle what you give it in a race car im sure some gentle highway ks wont worry 1 at all,thanks again for the input