pleadingbark Posted November 14, 2011 Share Posted November 14, 2011 This past weekend I picked up a set of triple weber DCOE 40's for my car (stock 70 240z L24 motor). They came off an L28 motor that made 150hp and were jetted as such. I have a few questions, first off I do have the jet sizes written down at home and will post them when I do get home. What type of ill effects will I see if I just slap the carbs on the car? The motor was a stock bottom end with an N42 head with Web Cam Grind #155 with 0.488 lift and 230 duration at 0.50. The head was worked a bit and decked and shaved, and the compression ratio went from 8.2 to 8.9 with that head. Would it be beneficial to keep the E31 head on, or would I just be better off snatching it off and putting this N42 on? I also have a Mallory 6al ignition that I need to figure out how to wire in (if anyone has a diy or anything I would appreciate it). Im not looking to really yank the motor due to the car being a 70 that just rolled to 70k miles yesterday and 1 previous owner. I also have a 6-1 header and will have an exhaust fabricated, if anyone has any size recommendations that would be awesome. Dont plan on taking the car to a race track, just something fun for the streets on the weekend. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted November 14, 2011 Share Posted November 14, 2011 (edited) So you have a stock e31 head? It should be fine if you just put them on. You may need to mess with the idle a bit because it was set to idle with a "hotter" cam and you have a stock one. You don't need to yank your motor out. Just run a 2.5in exhaust. I would recommend upgrading your dizzy to an electronic one from a 280zx before putting in the 6al unit. I believe that there are wiring diagrams online for how it should be wired up, maybe even on the Mallory site. If not call them, or ask the guy you bought it from. Edited November 14, 2011 by BluDestiny Quote Link to comment Share on other sites More sharing options...
madkaw Posted November 14, 2011 Share Posted November 14, 2011 If it were me, I would do one step at a time. I would bolt on the head with your carbs now-assuming that they are SU's and in good working order. You start changing things around too much at one time and if you have problems it is harder to diagnose.The n42 is a good head, but do you really know if it's ready to go and in running condition. I would just get rid of that lousy e31 head and give it to me-its no good for anything As far as weber stuff, posting the jet sizes would help the members see where you are at with the sizing. Quote Link to comment Share on other sites More sharing options...
pleadingbark Posted November 14, 2011 Author Share Posted November 14, 2011 So you have a stock e31 head? It should be fine if you just put them on. You may need to mess with the idle a bit because it was set to idle with a "hotter" cam and you have a stock one. You don't need to yank your motor out. Just run a 2.5in exhaust. I would recommend upgrading your dizzy to an electronic one from a 280zx before putting in the 6al unit. I believe that there are wiring diagrams online for how it should be wired up, maybe even on the Mallory site. If not call them, or ask the guy you bought it from. I forgot to mention its got a pertronix unit on it already with a flame thrower 3ohm coil and 7mm bosch plug wires. The plugs are gaped at .044 and are those NGK's that were recommended with that set up. Timing is also at about 15-16 degrees. Will going from a 2.8l to a 2.4l be a huge difference? Quote Link to comment Share on other sites More sharing options...
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