350-454

[dank4569]

I have a 71 chevelle with a 350 in it. I want to replace the 350 with the 454. Will the 454 drop right in or will i have to move the mounts?

[68chevelle]

the mounts should actualy be the same. i know for my 68 the motor mounts are the same for small blocks and big blocks. you will run into other problems with other things though. if you have power brakes you might run into problems with the booster clearing the valve cover depending on the booster and valve covers you have, and also the brackets for alot of the things on the front of the engine are different, and mount different.

[dank4569]

thanks for your help. One of my friends told me that the mounts would have to be moved, and then the radiator would get in the way. Thats why i was asking.

[68chevelle]

as far as that the answer is no for sure. the only posible thing is that the mounts might need to be moved, but the engine will not move front to back at all. it will bolt right up to your tranny and will sit just about the same distance forward as the small block if not the edzact distance, i dont remmeber if the big blocks casting is any longer or not, but anyway it would be much at all. so nothign to worry about there. i would probably sugjest getting new mount even if your old ones will work. just because they are worn and the big block will have mroe torque.

[DGB454]

My 72 originally came with a 454. I blew up the original and dropped in a 350 for a while. It bolted right in. The only thing I had to change was the radiator shroud. The fan wasn't close enough to keep it cool. I am back to a 454 from a 71 Chevelle and it also just bolted right in. The only thing that needed changing was again the radiator shroud. I did replace the motor mounts but only for the reasons 68Chevelle gave.

[dank4569]

What was involved in moving the radiator shroud?

[DGB454]

I didn't actually move it I bought a new shroud that was longer for the 350. When I went back to the 454 I put the stock shroud back on.
The shroud is the plastic circular shaped piece that that sits between your fan and the radiator. It helps to draw in the air from the fan. It bolts in very easily with just a few bolts. The only thing you might have to do is remove the fan so it can slide in. Very easy job.