Cam Swap Help

[L31MaxExpress]

Read any of his posts, the guy has had every Chevy V8 imaginable with every aftermarket cam and they all made great power. I'm pretty sure he spends all of his time swapping out engines. He also thinks a cam swap is a minor job and no engine will ever beat a big block. Cool story, bro.

I have had ALOT of GM V8s and a lot of V8s over the years I have been playing with cars and trucks. Some made great power. Some ran like crap. To me the Marine cam falls into one of those areas where personally I would not waste my time swapping it in. FWIW all these people claiming it runs fine on the stock tune. I had to bump the idle and desensitize the misfire monitoring to keep it from continually throwing P0300 codes at idle. However that being said I have had to do that on every cammed L31 or LS engine I have messed with anyway.

 

[slowburb]

Funny. The '395 cam in my 0.040" over/decked block L31 with 0.028 GM head gaskets ran without a single misfire on the stock tune for thousands of miles; at idle, part throttle, tip in, or WOT. Maybe I'm doing it wrong.

 

[L31MaxExpress]

Funny. The '395 cam in my 0.040" over/decked block L31 with 0.028 GM head gaskets ran without a single misfire on the stock tune for thousands of miles; at idle, part throttle, tip in, or WOT. Maybe I'm doing it wrong.

Maybe my 0411 is just more sensitive when it comes to misfire detection than the black box? Keep in mind I also ran mine with 1.7 rockers and my 906 heads had 2.02/1.60 valves. I also had headers and a full exhaust. Mine had a very noticeably choppy idle at the stock 550 rpm idle. I ended up raising it up to 750 because I have a looser than stock converter and underdrive pulleys.

I also know the fuel trims were all over the place with the 395' cam. Idle and Off-idle were rich and part-throttle midrange above 1,500 rpm were very lean. I had +10% fuel trims in some places and -15% in others.

 

[slowburb]

Headers and full exhaust here also, and catless, and without EGR. And an S10 converter. Still no misfires.

 

[Awest623]

Maybe my 0411 is just more sensitive when it comes to misfire detection than the black box? Keep in mind I also ran mine with 1.7 rockers and my 906 heads had 2.02/1.60 valves. I also had headers and a full exhaust. Mine had a very noticeably choppy idle at the stock 550 rpm idle. I ended up raising it up to 750 because I have a looser than stock converter and underdrive pulleys.

I also know the fuel trims were all over the place with the 395' cam. Idle and Off-idle were rich and part-throttle midrange above 1,500 rpm were very lean. I had +10% fuel trims in some places and -15% in others.

Listen man. If you're telling the truth, I appreciate it. But I've already decided what components Imma use and how Imma go about this. Now I'd appreciate if everything regarding that would end here. I don't want this thread getting derailed with arguments for and against certain setups. Thank you. Now if y'all have any installation tips that'd be nice. Since I'm going for low end power should I pretension the rocker arms 1 turn past zero slack (I don't remember the correct term for that)

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[94burbk1500]

Listen man. If you're telling the truth, I appreciate it. But I've already decided what components Imma use and how Imma go about this. Now I'd appreciate if everything regarding that would end here. I don't want this thread getting derailed with arguments for and against certain setups. Thank you. Now if y'all have any installation tips that'd be nice. Since I'm going for low end power should I pretension the rocker arms 1 turn past zero slack (I don't remember the correct term for that)

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Sorry fro the derail

 

[Awest623]

Sorry fro the derail

It's ok. I enjoyed it a little. Just don't want it to go too far and screw up the thread

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[L31MaxExpress]

Headers and full exhaust here also, and catless, and without EGR. And an S10 converter. Still no misfires.

Also without EGR here. Might as well be catless too with the thunderbolt spun race cats I run.

The F-car LT1 cam and 1.6 rocker setup I put in my brothers 1999 Suburban also set P0300 codes at idle.

I also always set my valves with the engine running and give them 1/2 turn lash. I have played with the lash anywhere between 1/4 and 1 full turn. 1/2 just seems to run the best. The OEM specified 1 turn seems to limit rpm potential and also seems to make less torque.

 

[L31MaxExpress]

It's ok. I enjoyed it a little. Just don't want it to go too far and screw up the thread

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Sorry for the derail as well. Just sharing my knowledge of what happened and what I thought about the setup while I was running it.

 

[Awest623]

Also without EGR here. Might as well be catless too with the thunderbolt spun race cats I run.

The F-car LT1 cam and 1.6 rocker setup I put in my brothers 1999 Suburban also set P0300 codes at idle.

I also always set my valves with the engine running and give them 1/2 turn lash. I have played with the lash anywhere between 1/4 and 1 full turn. 1/2 just seems to run the best. The OEM specified 1 turn seems to limit rpm potential and also seems to make less torque.

I've heard anywhere from 1/4 to 1 turn just depending on someone's preference. So I should shoot for half or a smidge over?

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