Questions for the Ol Wise Buick Guys

[Guest]

Here is what I currently have: <BR>1966 2dr Skylark (300V8/ST300)<P>Here is what I am looking at swapping in:<BR>1969 430/TH400 <P>(1)-Can a ST300 bolt up to a 430? Or it isn't possible, and I should go with the TH400?<P>(2)-Will I need another driveshaft? New motor/trans mounts?<P>(3)-If I go with the 430/TH400, will my 2.78:1's be ok?<P>(4)-What kind of gains should I expect with a 430/TH400 set up? (~15.5 1/4 times currently)<P>(5)-What gas can I run the 430 with?<P>***Thank you in advance for any help/suggestions... I am currently talking with a local guy about purchasing this combo to swap in. So I want to be perfectly sure of all that will be involved before I go ahead with the deal. Again, Thankyou!!!<P>-->The New Kid<P>(4)-There will be a huge jump in power/performance for the Lark, right?

[The Old Guy]

The ST300 will not bolt up to a 430. The th400 if it is the one with the short tail shaft ,will work. You will need new motor mounts and a different drive shaft as the fron yoke for the TH400 is larger.The 430 is a high compression engine and need 93 octane or better.The 2.78 axle will work,but you will need a posi or you will melt the right rear tire.You should help your 1/4 mile time by a second or more depending on how the car hooks up

[Guest]

I did this exact swap back in the 92.<BR>Heres what I did.<BR>I took a 1970 Wildcat 4 dr for a donor car<BR>I used the 455 motor mounts and mounted to the factory 300 frame pads with metal tube spacers to prevent the motor from sliding forward. I used the long shaft 400 tranny by moving the tranny crossmember back.I had the factory wildcat driveshaft shortened and used that.This car had the 278 posi rear. great on gas and fun to drive. Total cost of conversion approx 200 dollars.

[Steve B]

The ST 300 from behind a 300 engine will bolt up to the 430 engine. I would not advise it, as I don't think it would last long. Poston and TA Performance makes frame pads to put a 400/430/455 into a 64-67 Skylark. They will line the engine up with your 300 trans and radiator. Or, you can use the 400 trans, move the crossmember back, and have your driveshaft shortened as suggested. The short 400 will provide a better pinion angle.

[The Old Guy]

Steve, thank you for catching my goof. I was thinking of the earlier trans for nail heads.

[Guest]

Well, there is some good news and some bad news...<P>Today my ST300 took a $hit on me, so it looks like I'm stuck with using the TH400 if I go through with the swap.<P>The guy that I am talking to said that I could have the 430 from carb to pan, and also the TH400 for $500... he said it should drop right in and be ok to drive regularly, but if I were to race it--well thats a given what will happen.<P>Any other comments/etc?<P>Thanks again.

[Guest]

I also did this swap<BR>The biggest problum I had is keeping the car cool The stock 300's 3 core radiator just isnt enough Ive installed a aluminum rad with 2 1 1/4' cores and it still runs on the high side Your shroud will not work with this setup you will need one from a 67 400<BR>$115 from year one <P>Jim