'66 chassis manual question

[Nemo]

Hi to everybody
newbie here.
Searching documentation to resolve my 'lark problem i've found the '66 chassis manual in "reference".
By what i've read the transmission st 400 were used on gs 340 and cars equiped with 400,401,425,430,455.
But also st 300 were used on cars equiped with 340 motors.
So by what i understand the st 300 and st 400 can be interchanged.
This mean also i can put a 400 engine on a st 300 trans.
All this considerations i've done only reading the manual and caused by
the necessity to put a new engine in the car ('lark 67 with st300).
So i'm asking to have the confirmation of more expert people.
Hoping in your help

[Dr. Frankenbuick]

Nemo,

Your best bet is a 340 or 350 Buick engine. They will bolt in place of the 300 engine with the same motor mounts and accessory drives. You will have to change the exhaust manifolds and exhaust, but it is a very easy swap. There were a lot of 350s made for many years while the 340 was a two year deal. Some of the big block Buick engines you mentioned will fit the ST 300, but they will make short work of it. The ST 300 was not intended for the big block (other then the 65-66 GS Skylark with a 401 nailhead and ST 300 that had extra clutches and only fits the nailhead engine).

[gag67sky]

Hi Nemo,

Don't know what you can find in Italy, but here in France find a 300 or 340 motor is not easy but can be done if you have time to spend....

It would keep your car close to original instead of the 350 that was issued since 68' only... and is not easier to find here though.

If you want and ask me, I can look for one in France....

Therefore do you realy need a new motor or maybe yours can be rebuilt???

Ciao, JC

[Nemo]

Thank you all for help and info.If i can put a 350 with my actual trans i believe i'll do it.Here in Italy there are some buicks enthusiasts but is not easy to find replacement parts.I think i will buy it in USA.Nice to see buick enthusiasts also in France JC,hope we can meet in some event dedicated to USA cars.

[gag67sky]

Hi, who knows ? It would be nice....

Ciao, JC

[Iceyviking]

Hi guys,

I have a 67 4 drht Skylark originally equipped with a 340 4bbl and a st300 tranny. I am currently in the process of swapping in a 350 since the 340 was gone beyond repair. The 350 is a direct swap, but you have to remove the valvecovers and the starter to get it in without too much hassle. My 350 is a -73. Not the best year performancewise, but hey, beggars can't be chosers, and here in Norway Buick engines are hard to come by, whatever size or year.

I did get a set of headers for it, so I expect it'll put out at least the same as the 340. I ran into a little problem with the motor mounts; they don't line up 100%, so I may have to massage them a little, but it is close enough that I am sure that they'll fit if I mount them loosely to allow for some minor adjustments.

My car has been stationary for two years now, so I can't wait to get it out again.

Let me know how the your projects are coming along. Looking at your -67 was like looking at mine which is also white. Nice.

[Nemo]

At the end i bebuilt the old 300 motor,is better to say refreshened because i have not remachined the cylinders and i conserved pistons.
Next week i have to do the cam break in and all tests and measurements about oil pressure and water temperature vacuum...i hope will be all right.