I'm planning on putting a 455 into my 70 Cutlass, currently a small block car. I plan on aluminum heads and intake, and was curious if I would still require the heavier duty big block springs in the front. Not sure what the weight difference is between stock and aftermarket. Might be a dumb question, just trying to save a few bucks! Thanks

 

With the aluminum heads and manifold you shoud be fine, I think it's an 80# difference between a SBO and a BBO. Try it and see, you can always do it down the road some.

 

x2 Eric's recommendation. Might not be any weight difference by the time you have aluminum heads and manifold.
Jerry

 

The difference between a stock 350 and a stock 455 is about 50 lbs. I've done this swap several times and never changed the springs - in fact, I've had to cut the springs to get the nose down to where I wanted it.

 

Thanks guys! Very helpfull and exactly what i wanted to hear!