350 lt9 mcode cam

[16slt6.2]

I got an 84 c20 with the heavy emissions mcode 350. I know there are some differences between it and a normal 350. Just wondering what a good mild cam would be to give it a bit more grunt. If someone could point me in the right direction that would be great. Thanks

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[1987 GMC Jimmy]

I think it would help you for sure. I feel bad that you're subject to the scrutiny of CA emissions regulations. A Comp 12-300-4 sounds like it'd be just what you're looking for. What else would you be allowed to do? A more modern catalytic converter and headers would help if they're approved, and a new intake would be nice if it was also approved. Do you have a smog pump on it, and are you running the E4ME Quadrajet? I'm not sure what's different between a half ton and a 3/4.

 

[16slt6.2]

I dont live in cali thats just where the truck is from so I can do whatever i want. Just dont know much about this engine

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[HotRodPC]

Being an 84 and a 3/4 ton with a higher GVWR, he's got a little liberty in CA too. He can still go mild and still pass tailpipe emissions. The older a vehicle is, and the heavier the GVWR is, the smoggier it can be.

Did 84 3/4 ton Cali trucks even have Cat Converters yet? I know the 1/2 tons did and the 1/2 tons were CCC by 84 too, but the 3/4 tons may not have been yet. I know 49 State Federal, 3/4 tons didn't get Cats until about 87 and I think that's cuz they went TBI. My 86 3/4 came factory with true dual exhaust and no cats, no unleaded fuel stickers and no unleaded fuel only on the gas gauge.

 

[1987 GMC Jimmy]

Oh, well no California likely means more liberty with your setup. Are there emissions regulations in your county/state? HRPC makes good points. Being a 3/4 ton may indicate a default reduction in the emissions junk that the 1/2 tons had.

 

[16slt6.2]

I live in Canada so im not to worried about emmisions. There is no cats on the truck it has an aftermarket system that was put on before i bought it.

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[75gmck25]

Just to give you an idea, look at the specs of the Summit Racing SBC Cams:

1101 - 194/204 @ .050 very similar to your stock cam.
1102 - 204/214 @ .050 . Similar to typical RV cams. Increased power, but still good economy.
1103 - 214/224 @ .050 . Still workable, but your low compression engine, stock heads, (and probably high gears) will limit its power.

If you are not making other changes I would probably use something in the 204/214 range.

Bruce

 

[16slt6.2]

I dont know much about these engines but would changing the heads be enough to run 214/224

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