This morning I was thinking about V8 engines, and....

[dodgedude37]

A 400 Cid is too much for a small block. I had a 400 in chevy & there was not enough water jackets to accommodate that much cubic in. As the bore got bigger the water jackets get smaller. Back in the day mopar was known for engineering so they new what no one else new.

 

[nutz]

Yup had bleed holes in the head
Had one in my supperburban..
78 suburban with a 400sbc with a 142 weinand blew the head gaskets and 6lb of boost ....she did run though and adv 14mpg

 

[65 Cuda 340]

A 400 Cid is too much for a small block. I had a 400 in chevy & there was not enough water jackets to accommodate that much cubic in. As the bore got bigger the water jackets get smaller. Back in the day mopar was known for engineering so they new what no one else new.

400 inch Chevy had siamesed bores, no way for coolant to get between the cylinders.

400 plus cubes in a Mopar small block do not present that problem.

 

[Jim Lusk]

Many of the other make displacements started in the 1950s when each Chrysler division had their own V8s in both hemi and poly head configurations. From 241 to 392 ci displacements. As the 1950s were coming to a close there was a need to simplify the offerings so it was settled on the Plymouth poly being the corporate small block (318) and the big block wedge being the corporate big block starting with the 350. When the LA 273 came out it didn't take long for the 318 to get a wedge head and then came the 340 followed by the 360. There never was a need to have all the other displacements and by the time 1974 rolled around there were four V8s (318, 360, 400, 440). Then the big blocks were dropped after 1978. The 318 and 360 served Chrysler well for a lot of years.

 

[Kern Dog]

400 inch Chevy had siamesed bores, no way for coolant to get between the cylinders.

400 plus cubes in a Mopar small block do not present that problem.

All you needed was a 4 inch stroke crank in a Mopar LA block. There was plenty of room, no clearancing of the block was needed.

 

[RustyRatRod]

A 400 Cid is too much for a small block. I had a 400 in chevy & there was not enough water jackets to accommodate that much cubic in. As the bore got bigger the water jackets get smaller. Back in the day mopar was known for engineering so they new what no one else new.

Not in Ford's case. The 351M and 400 are both large physically for small blocks. They have plenty of water jacket area.

 

[polyjohn]

Well, well, Mother Mopar got away with the LA series as it was a 318 Poly Block design.
Incorrect lifter angles for the LA wedge head and millions were made!

Mother Mopar could have done a head re-design on the 318 Poly head but didn't.
But us Poly lovers know the potential in 'iron' Poly heads and are happy to go 402 cubes.

4 inch bore and a 4 inch throw and 500 horsepower is possible.
They can also be 390 cubes but that sounds like a Ford number to me...