Well this may seem dumb :0 but the one thing that comes to my mind is different suspension up front. A big block carries more weight than that little 283. Beef up the front end or else try to look cool with the front end dragging on the 'ol two-lane.
[This message has been edited by Coppertop (edited 07-11-99).]
Don, Coppertop has a point. The fat motor is going to put a hurtin on the small block springs. Either swap in big block springs or find a way to lighten up the front end, ie, alum. heads, glass hood, etc,. If you can knock off about 125-150 pounds you can leave the springs alone. The motor mounts you have will work but you going to have to shim up the motor mounts on the block. Use good quality machined flat washers between the block and the motor mount. shim the mounts about 1/4 to 3/8 inch away from the block. Understand that by doing this your raising the engine slightly and hood clearance is already at a premium, so watch that air cleaner stud!! As for the tranny, your bell housing will bolt right up.
I've done this swap with great success without changing springs or shimming the small block mounts. Get someone to stand on the bumper who weighs 130 to 150 pounds, this will let you know if you can get by with your original springs. If they haven't collapsed from a zillion miles you'll probably be ok. The one part you will need is a dedicated Chevelle oil pan.It is different from the Impala, Camaro, Nova, Truck pans as they will not clear the crossmember or inner tie rod ends.
I have to agree with 68396, I recently pulled my small block for the big. The springs didn't seem to mind the extra weight.But, I'll be keeping my eye on them to make sure they don't start to get saggy. Also,I used the mounts right off the small block. No shims were nessisary between the engine and mount. I will admit I am fairly new to swapping small blocks for big blocks but, Should I be shimming the motor mounts? It seems to fit in nicely. Or should the engine be raised up 1/4 inch?
I've investigated this mission and spoke to a couple of people that did this - Oil pan for a Chevelle OR a Monte Carlo of the same year. Motor mounts OK. New radiator shroud. And REALLY GOOD, Hi-Quality headers. Why? They have to fit the first time or you wil GO NUTS getting them in. As for springs. You'll have peace of mind with proper springs so your header collectors aren't subject to hits on speed bumps and rolling roads.
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