1985 Caprice
djames
02-17-2004, 05:23 PM
I will be purchasing an 85 in a few months from my father that is in great condition. Everything is stock right down to the 305 and 4brl carb. The carb has been rebuilt but I'm wondering about a whole new intake and what is compatible with these cars without pulling the engine for a larger cam. I want to do as much as possible while leaving the engine in the car.
I haven't been under one of these cars in a while and also want to know about dual exhaust.
Is it possible to run a true dual from the stock exhaust manifold and not have to worry about smog?
I haven't been under one of these cars in a while and also want to know about dual exhaust.
Is it possible to run a true dual from the stock exhaust manifold and not have to worry about smog?
quaddriver
02-18-2004, 03:08 PM
I will be purchasing an 85 in a few months from my father that is in great condition. Everything is stock right down to the 305 and 4brl carb. The carb has been rebuilt but I'm wondering about a whole new intake and what is compatible with these cars without pulling the engine for a larger cam. I want to do as much as possible while leaving the engine in the car.
I haven't been under one of these cars in a while and also want to know about dual exhaust.
Is it possible to run a true dual from the stock exhaust manifold and not have to worry about smog?
You should be able to find a plethora of SBC intakes that will accept the Qjet carb and have all the funny passages drilled. Hood clearance is really your only issue. The 85 is the first year using a KS and as a result, has half a point more compression and slightly larger intake valves giving it the 165hp rating...you can help this a little with a true dual setup but the problem there is no 'double bump' tranny crossmember....rather than fight this, just goto a slightly larger Y pipe (goto advance and autozone and spec the Y pipe, cat, and exhaust from the same year police 350 - which was also single) I did this on my 85 wagon (yes, some cops ran wagons for DOT stuff) and it made a satisfying difference...leave the cat in, todays cats are so unrestrictive that cleaning up the environment is free and keeps you out of trouble should anyone peek underneath.
Another free 5hp at WOT is to ditch the single snorkel intake for a dual....either cut and weld another snorke or find a car that had duals, however the effectivness of this is diminished if you dont change the cam - the stock 85 H code cam is made for power up to 4000, it falls off rapidly over 4000 and this is where the dual snorkle would help. just increase the grind a WEE bit, or cheaper yet, install 1.6 ratio rockers on the heads, this has the net effect of more valve lift and the 5.0G block will take it.
Leave the emissions intact, my 85 just passed MD emissions to the person I just sold it to...not bad considering age and mileage.
I haven't been under one of these cars in a while and also want to know about dual exhaust.
Is it possible to run a true dual from the stock exhaust manifold and not have to worry about smog?
You should be able to find a plethora of SBC intakes that will accept the Qjet carb and have all the funny passages drilled. Hood clearance is really your only issue. The 85 is the first year using a KS and as a result, has half a point more compression and slightly larger intake valves giving it the 165hp rating...you can help this a little with a true dual setup but the problem there is no 'double bump' tranny crossmember....rather than fight this, just goto a slightly larger Y pipe (goto advance and autozone and spec the Y pipe, cat, and exhaust from the same year police 350 - which was also single) I did this on my 85 wagon (yes, some cops ran wagons for DOT stuff) and it made a satisfying difference...leave the cat in, todays cats are so unrestrictive that cleaning up the environment is free and keeps you out of trouble should anyone peek underneath.
Another free 5hp at WOT is to ditch the single snorkel intake for a dual....either cut and weld another snorke or find a car that had duals, however the effectivness of this is diminished if you dont change the cam - the stock 85 H code cam is made for power up to 4000, it falls off rapidly over 4000 and this is where the dual snorkle would help. just increase the grind a WEE bit, or cheaper yet, install 1.6 ratio rockers on the heads, this has the net effect of more valve lift and the 5.0G block will take it.
Leave the emissions intact, my 85 just passed MD emissions to the person I just sold it to...not bad considering age and mileage.
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