'68 GS 400 engine swap to 455

hello,i'm new at this.I have a '68 GS 400 and am thinking about dropping in a 455.Will it fit right in,or any mods needed ?
thanks

 

Hello Tohiggs:



Please put your name in your signature, we're all on a friendly first name base :TU:


The engine dimensions are the same for a 400 and a 455:

Click here :Smarty:

 

Hi Tohiggs welcome aboard , yes all 400/430/455 are the same animal, just different size slugs. Good luck with the swap. :TU:

 

Thanks.

 

Hi There.You may want to consider using some of your 400 pieces if your 455 is a 75-76 complete for example.The 400 heads,carb and intake would be better suited for performance than the later 455 parts.A 70-74 455 would still be a good runner in stock form also if this is what you have.Lots of past posts here on 400/430 rockers,oiling etc on 455 blocks.Good Luck.Later,Tony.

 

Use the 455 short block with your 400 heads and intake. Use the 455 rocker arms and pushrods. You also need to use 70-up lifters on whatever cam you use.