RyanisBRUTAL

I blew the original 350 small block in my '74 c3 and a friend wants to sell me a chevy 400 small block from his el camino for $400.. a lot less than I could get a new 350 for. I'm just wondering if there's anything big I should be aware of in making this swap. Bigger engine more power right?

jackson

400's generate a bit more heat ... and they need a cooling system in tip-top shape. If possible do a real good system cleaning on BOTH el camino & vette ... BEFORE you swap. GM P/N 12346500 cleaner at some GM dealers is best there is. Get a canister for each car.

Gordonm

A stock 400 does not produce much power. Bad heads and low compression and a small cam. Give it a bigger cam with good heads and some compression and good exhaust and it will make some good power. The only thing I find useful on a 400 is the block. The rest is not high performance.

RyanisBRUTAL

Ok thanks for the advice. In that case, what can I take from my 350 to use on the 400 that will give me more power? The 350 has a blown rod.

73VetteKS

All the 350 parts, heads, intake, cam, exhaust, etc... will work on the 400.
Couple of things to be aware of.
1). Be sure to drill the steam holes in the heads.
2) If you have power steering on the Vette, be sure to check the front of the block to be sure the threaded holes are there for the PS mount. Most if not all 400's are not tapped/threaded. If it is not, you will want to drill and tap before you install the motor in the Vett.
-Jim

L Holmes

Can someone elaborate more on "drilling steam holes" Im assuming this is a difference in the heads the 400 uses?

lan dannon

400's have steam holes between the cylinder bores with corespondings holes in the heads. The holes have to be drilled in the water jackets of the heads without these holes. One hole is straight in and the other is at an angle. The holes are very important. You will have overheating problems without them.