11-08-2009, 03:23 PM
The table below should give you an idea of the similarities and differences in chamber volume and valve diameters. You will be able to see how the 351C stacks up against the 302, 351W and 390 and why the 351C is capable of huge performance. Some comparisons appear after the table.
Let's look at some comparisons. If you have any doubt about the Cleveland heads breathing well, compare the valve diameters to the 390, 427, 428 and even the 460 Police Interceptor. The Cleveland 4V has a bigger intake valve than any of the other engines except the 460 Police Interceptor! The 351C 4V exhaust valve is only 0.020" smaller diameter than the 460 PI, and only 0.010" smaller than the high performance 427. Even the lowly 351C 2V has intake valves larger than the high performance 390's and 428's, and the exhausts are larger than all 390's and some 427's, 428's and 460's.
Looking at the Intake Port of the 351C 2V, you will see that it is larger than the 390, 428 and some 427's and 460's (multiply the two dimensions). So, while the displacement in the 351C is obviously less than the 390, 427, 428 and 460, it is designed to breathe better than the others and it has fewer cubic inches to breathe (fill and empty). This is why the Clevelands Rock!
If you want to compare the 351W to the 351C, you will see that the 351W looks more like a 302 head and the 351C looks more like a standard 427 or 428 head!
So how do you identify the different Cleveland heads?
Windsor heads have the valves in a nice straight line.
These are 69 Windsor heads.
The basic 351C 2V has staggered valves.
The 351C 4V has staggered valves and HUGE ports with closed chambers.
The Aussie heads have closed chambers, like the 4V,
and the 2V sized ports.
You can identify the 2V, 4V and M heads while the engine is still in the car. Cast into the head (raised) is either a "2", a "4" or an "M". These are located on the valve-side of the head (not the block side) near the intake (not the exhaust ports) in the upper left corner. This means that as you stand on the driver's side of the engine (US steering) and look at the head through the AC crapola, just above the valve cover on the left end of the head, you will see the marking.
Let's look at some comparisons. If you have any doubt about the Cleveland heads breathing well, compare the valve diameters to the 390, 427, 428 and even the 460 Police Interceptor. The Cleveland 4V has a bigger intake valve than any of the other engines except the 460 Police Interceptor! The 351C 4V exhaust valve is only 0.020" smaller diameter than the 460 PI, and only 0.010" smaller than the high performance 427. Even the lowly 351C 2V has intake valves larger than the high performance 390's and 428's, and the exhausts are larger than all 390's and some 427's, 428's and 460's.
Looking at the Intake Port of the 351C 2V, you will see that it is larger than the 390, 428 and some 427's and 460's (multiply the two dimensions). So, while the displacement in the 351C is obviously less than the 390, 427, 428 and 460, it is designed to breathe better than the others and it has fewer cubic inches to breathe (fill and empty). This is why the Clevelands Rock!
If you want to compare the 351W to the 351C, you will see that the 351W looks more like a 302 head and the 351C looks more like a standard 427 or 428 head!
So how do you identify the different Cleveland heads?
Windsor heads have the valves in a nice straight line.
These are 69 Windsor heads.
The basic 351C 2V has staggered valves.
The 351C 4V has staggered valves and HUGE ports with closed chambers.
The Aussie heads have closed chambers, like the 4V,
and the 2V sized ports.
You can identify the 2V, 4V and M heads while the engine is still in the car. Cast into the head (raised) is either a "2", a "4" or an "M". These are located on the valve-side of the head (not the block side) near the intake (not the exhaust ports) in the upper left corner. This means that as you stand on the driver's side of the engine (US steering) and look at the head through the AC crapola, just above the valve cover on the left end of the head, you will see the marking.
C.L.
JTS 71 Mach1
![[-]](https://mach1club.com/images/collapse.png "[-]")
