72 340 pass side manifold
really good thread - old but very relevant, and I'd like to hop on this 'musical manifolds' train with another manifold question, but regarding 'truck engines'.
I'm building an 02 Magnum 360 - stock long block save for a Comp Cams cam (#20-745-9: 212-218 (264/270), .480/.480, on a 114* LSA), Eddy 7577 intake and Sniper 2300 2bbl. I'm building it for 'off-roading and camping', not racing. The cam will be 'done' at 4500 rpm, and I'm only concerned with low end torque and efficiency - no cares for how well the manifolds will flow above 4500 rpm - I'll just be adding gears.
The nature of my chassis (02 Dakota, about 6000 lbs) hugely appreciates center dump manifolds - much easier to maintain and a ton less heat around critical components than the OE 'rear exit', and a friend of mine has a pair of the '71 p-side 340 manifolds (623s with the 1-7/8" outlets) I can likely get fairly cheap.
My other option is a pair of the 70's era pre-smog truck manifolds (3830684), also with the 1-7/8 outlets. These appear to have bigger 'insides' than the 623s...but not sure these would perform any better than the 623s...for me. The other fine point is there generally seems to be more 'meat' around the mounting bolts with these later 70's manifolds, but the 623s I'm looking at look to have a good amount there (1st pic), and I'm leaning towards the 340 manifolds for my truck.
Interesting note - both sides of the 02 magnum manifolds also have 1-7/8" outlets, just like the 623s and 684s, and I have to believe that...for my 'truck' application...the 623's will flow equally as well as the OE magnum manifolds up to 4500 rpm...maybe even higher, and I gain all of the benefits of the center dump setup that I would very much like to achieve.
I am not concerned about losing 10 hp, but from a low-end torque/efficiency standpoint, can anyone think of any reason(s) the 623s or 684s would be a poor choice? Thanks all
623s (71 340 p-side) - my leading choice for both sides of my 360 -
684s (mid-late 70's truck, pre-smog) - other than 'internal space' and more cooling fins there doesn't appear to be much different from these and the 340 units...? -
02 Magnum 318/360 -
- Sam
really good thread - old but very relevant, and I'd like to hop on this 'musical manifolds' train with another manifold question, but regarding 'truck engines'.
I'm building an 02 Magnum 360 - stock long block save for a Comp Cams cam (#20-745-9: 212-218 (264/270), .480/.480, on a 114* LSA), Eddy 7577 intake and Sniper 2300 2bbl. I'm building it for 'off-roading and camping', not racing. The cam will be 'done' at 4500 rpm, and I'm only concerned with low end torque and efficiency - no cares for how well the manifolds will flow above 4500 rpm - I'll just be adding gears.
The nature of my chassis (02 Dakota, about 6000 lbs) hugely appreciates center dump manifolds - much easier to maintain and a ton less heat around critical components than the OE 'rear exit', and a friend of mine has a pair of the '71 p-side 340 manifolds (623s with the 1-7/8" outlets) I can likely get fairly cheap.
My other option is a pair of the 70's era pre-smog truck manifolds (3830684), also with the 1-7/8 outlets. These appear to have bigger 'insides' than the 623s...but not sure these would perform any better than the 623s...for me. The other fine point is there generally seems to be more 'meat' around the mounting bolts with these later 70's manifolds, but the 623s I'm looking at look to have a good amount there (1st pic), and I'm leaning towards the 340 manifolds for my truck.
Interesting note - both sides of the 02 magnum manifolds also have 1-7/8" outlets, just like the 623s and 684s, and I have to believe that...for my 'truck' application...the 623's will flow equally as well as the OE magnum manifolds up to 4500 rpm...maybe even higher, and I gain all of the benefits of the center dump setup that I would very much like to achieve.
I am not concerned about losing 10 hp, but from a low-end torque/efficiency standpoint, can anyone think of any reason(s) the 623s or 684s would be a poor choice? Thanks all
623s (71 340 p-side) - my leading choice for both sides of my 360 -
684s (mid-late 70's truck, pre-smog) - other than 'internal space' and more cooling fins there doesn't appear to be much different from these and the 340 units...? -
02 Magnum 318/360 -
- Sam