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What is the difference between a Pontiac 400 and a Pontiac 455?
Wiki User
∙ 15y ago
The Pontiac 400 has a bore of 4.12 and a stroke of 3.75. The Pontiac 455 has a bore of 4.15 and a stroke of 4.21. The 455 cylinder heads will have larger combustion chambers than the same year 400 heads to achieve comperable compression ratios on the larger engine. The blocks are physically the same size, but 455 has larger main bearings than the 400. 455=3.25 400=3.00, so crankshafts will not interchange. Cams,heads,intakes,exhaust,connecting rods,push rods,rocker arms...etc will all interchange.
Wiki User
∙ 15y ago
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What is the difference in the gm engine 400 and 455?
If you mean the difference between the Pontiac 400 and 455....the differences are the bore size, the crank stroke length, and the main bearing journals. All are bigger on the 455. However, there is also a small block Chevy 400....which has nothing the same as the other two. The Pontiac 400 has a bore of 4.12, stroke 3.75 and 3" main journals. The 455 has a bore of 4.151, stroke of 4.21, and 3.25" main journals.
You have the belt set up from a 1968 Pontiac Bonneville with a 400 engine was replaced with a 1973 Pontiac grand ville with a 455 The water pump shaft is too long and the pulleys do not line up what?
you probibly need to change the water pump to a newer year. there is no difference between the 400 and the 455 besides the year. if you use the pump for the 455 it should work or go to the salvage yard and get pully setup for the 455.
What is the horsepower rating on a 1974 Pontiac grand prix 400 engine?
# the 400 had 225 horse ..........the 455 had 250 horse.
What engine comes on 1979 Pontiac Bonneville?
301 302 305 350 400 455
What motors come in a Pontiac gto?
1964-1966: 389 CID. 1967-1969: 400 CID. 1970-1972: 400 or 455 CID.
How do you set distubitor timing on Pontiac 455?
How do you set distubitor timing on pontiac 455?
Is a Pontiac a small block?
Depends on which Pontiac engine you are referring to. Any GM engine 400 cubic inches and under are considered a small block with two exceptions. The 396 is a big block and there were certain 400's that are big blocks. Two versions of the 400 were built.WRONG. All Pontiacs from 326-455 are the same size block externally. The only major difference is that the 326, 350, 389, and 400 have a 3" main bearing size. The 421, 428, and 455 are 3.25" mains. Now...if you are talking about comparing a Pontiac block to say a Chevy block....the Pontiac is larger than a small block and slightly smaller than a big block.
What is the firing order for a 1973 Pontiac LeMans?
Answer6 cyl = 153624, clockwise rotation350 & 400 &455 = 18436572, clockwiseWRONG...All Pontiac V8 engines rotate counter clockwise.
400 firebird big block or small?
There is no "small block" , "big block" with Pontiac engines. The physical size is the same from 326ci to the 455.
Is Pontiac 455 heads exchangeable with Oldsmobile 455?
No, they are completely different.
Can a intake manifold and other parts be interchanged between a olds 455 and a olds 400?
No.
How many miles per gallon on a 1975 Pontiac Granville?
With either the 400 or 455 engine this car is a gas hog. You will be lucky to get 15 mpg.
