I have recently bought a 1970 malibu,I was told it was a 350ci, but to my suprise or
demize it was a 400 small block original motor.I have heard some bad things about
over heating,can any body tell me if I was
Consider yourself lucky. 400's are getting scarce. I just built a 70 400 for my 69. It is street legal and runs low 12s on pump gas. Never runs over 190 degrees. If you don't want the engine, you have excellent trading material. It should bring a good price. BTW only 70 400s have 4 bolt mains.
It is universally agreed that there were NOT any SB400s in the Chevelles, just the Montes. Buuuuuuuuuuuuuut-----------------, strange things have been known to happen. This car would have to be documented with a build sheet and the VIN stamped on the block (but then it would still have to be notorized by God).
Although it really doesn't matter if it is original or not. As mentioned, SB400s are getting scarce. When properly built, with heads that have the extra cooling holes for steam and a good cooling system, you should have no problems with overheating. They make an excellent performance or daily driver engine.
The 70-72 SB400s, all, without exception, were 4bolt. Then the 73-later 400s were 2bolt ONLY. I promise.
I have a 400 in my 71 chevelle. I yanked the original 350 and stuffed it in the corner of the garage! As mentioned you should have no cooling problems if you have a well set up cooling system. Some guys recomend big block 4 core radiators and such, I feel this is overkill. I got a brand new 3 core radiator and it cools fine. I have air conditioning on the car and have drove it in 95 degree heat all day long on road trips with no overheating problems. They do overheat faster if your cooling system is not up to par because they have siameased cylinder walls. A 350 allows coolant between the cylinder walls and the 400 does not. This is why 400 heads must have the "steam holes" in them to allow coolant to pass better between the heads and block. If your running a small block I think the 400 is the only way to go. A 350 will never touch the torque of a 400. It can produce big-block type power numbers without the extra weight a big block gives you. Sure a built big block will still produce more power than any small block but I would run my 400 small block against a stock 375 horse big block any day.
There is also a VERY easy cooling system modification that can be done to early 400's. (later 400's have it from the factory) that involves drilling one hole in each deck, and a matching hole in each head, and head gasket. Lohn Lingenfelter's small block Chevy book has details on Pg. 20.
I used to have a strong 400. Never had any real cooling problems after I put a Good water pump on it. 180 to 190 no matter how hot it was out side. I even had the steam holes plugged with lead so any type of head could be used. We figured that if it got hot enough to melt the lead it was already junk! It never got hot and it ran and ran and ran. It is now sitting in the corner of the garage tore down and it is still in great shape. Just my $.02.
Coppertop it turns out you are right, the the back seat where I found my build sheet Half eaten was probably A seat from a monte.. <BLOCKQUOTE>quote:</font><HR>Originally posted by Coppertop: THERE IS NO SUCH THING AS AN ORIGINAL 1970 MALIBU WITH A 400 SMALL BLOCK!!!
A 400 small block was only available in the '70 Monte Carlos.
There is such a thing as a 400 Malibu though, check out my page:
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