Mr.FT
Well-Known Member
Just curious on if there is any advantage to putting 360 heads on a 340 with J heads? Juet curious as someone told me that the 360 heads breath better. Any truth to this?
340-360 Head Question?
- Thread starter Mr.FT
- Start date
-
No truth to the breathing..... in fact, your "J" heads would be the better breathing head.
Any advantage for the 360 heads?? Well, if they are not the 1st year 360 head, they most likely will have hardened seats for todays fuels.
Unless they are talking about the magnum heads.... then it's a whole different ball game, including the installation.
Any advantage for the 360 heads?? Well, if they are not the 1st year 360 head, they most likely will have hardened seats for todays fuels.
Unless they are talking about the magnum heads.... then it's a whole different ball game, including the installation.
Same valve size, no real difference in performance. Later heads would have hardened seats for unleaded fuel.
Only way it could be better would be to take a 1.88 head, have a good valve job, throat cut for a 2.02. That would work better than any factory installed 340/360 shaft mount head.
Only way it could be better would be to take a 1.88 head, have a good valve job, throat cut for a 2.02. That would work better than any factory installed 340/360 shaft mount head.
In some years, the 340 and 360 heads were the same...
Early 340's had 2.02" intakes, where the 360 and later 340 had 1.88" valves...
You can have a machinist put the 2.02" intakes in and they will be just like the old 340 heads... Not much difference...
Early 340's had 2.02" intakes, where the 360 and later 340 had 1.88" valves...
You can have a machinist put the 2.02" intakes in and they will be just like the old 340 heads... Not much difference...
Locomotion
Well-Known Member
J heads came with 1.88" (340 & 360) or 2.02" (340 only) intake valves. Later 360 heads (i.e.: 587, 051, 974) all had 1.88" intakes with very similar and flow numbers. Flow would likely be influenced more by the quality of the valve job than the OEM port shape. Some people like the much later 308/576 heads, which is often debated. There are flow # charts online, but often they were not done on the same flow bench, or there may be other unknown influences involved. But they are an interesting reference.
New seats in worn heads or opening up a 1.88" head to 2.02" with a fresh, high valve seat will help, as will stainless nail-head intakes. Exhaust valves are said to like a tulip style head. In my opinion, smoothing out the bowl area and port touch-up would offer the most benefit for least amount of labor after a good valve job.
New seats in worn heads or opening up a 1.88" head to 2.02" with a fresh, high valve seat will help, as will stainless nail-head intakes. Exhaust valves are said to like a tulip style head. In my opinion, smoothing out the bowl area and port touch-up would offer the most benefit for least amount of labor after a good valve job.
^^^^^ I had a set of "J" heads I took off a 340 and it had 2.02's. I also agree that working the bowl area is huge.
-
