Cam advice

[GMCBurb99]

First off I’ve been on here for a while now and have gathered some great info, but have a question and this is my first post.
I have a 99 GMC Burb 2wd and I’m planning on heads, cam, 36lb injectors from AUS Injection, and dynotune later this winter. Was planning on going with NKB 200cc heads with PRW 1.6 rockers, but having trouble deciding on a cam. I was planning on sticking with the factory stall, but a higher stall isn’t out of the question. I’ve looked at the LT4 hot cam, the SP350/357, Lunati Voodoo, Howards cam part#181145-12, and a few others. Just trying to figure out one that’s going to work well with the heads, keep power down low, but also have good power up through 5800. Also would those heads be too much? Should I drop to something like 180cc? Hope these aren’t stupid questions, but just wanting the right combo and especially for the weight of this suburban. Thanks in advance.

 

[L31MaxExpress]

The NKB 200s flow very well. Similarly to the Assault 200cc head castings I built with good parts, did minimal cleanup and a good valve job to. I had those on the old L31 350 in my van. 200cc port works well on a 350 provided you do not over cam it. I have messed with several different cam setups. Having run a variety of setups, dual pattern cams are practically pointless. Many cam manufactures go 6-10* bigger on the exhaust lobes. That is absolutely a waste of time on a 5,500 rpm truck engine. Go single pattern and tighten the LSA a bit. Most cam manufactures will spec you something around 204/214 or 206/212 or 212/218 on a 112 LSA. Something like a 206/206 on a 108 or 212/212 on a 110 will make more average torque. On Comp Cams HORRIBLE advice and recomendation, I have a 218/228 on a 108 in the 383 in my van currently. It is completely wrong for what I want myself. I have a custom grind Erson 219/219 on a 112 to replace it with that Lloyd Elliot and I conversed and decided on would be a much better fit. The Erson should have a nice smooth, near stock idle, pull low rpm without bucking and surging and deliver better mileage. The Comp Cam has too much overlap and the IVC is too early making it octane sensitive and it has a misfire induced shudder under 1,500 rpm when it is under load. I end up cruising around with an unlocked torque converter under 50-60 mph because of it.

 

[L31MaxExpress]

Are you running headers on this?

 

[GMCBurb99]

The NKB 200s flow very well. Similarly to the Assault 200cc head castings I built with good parts, did minimal cleanup and a good valve job to. I had those on the old L31 350 in my van. 200cc port works well on a 350 provided you do not over cam it. I have messed with several different cam setups. Having run a variety of setups, dual pattern cams are practically pointless. Many cam manufactures go 6-10* bigger on the exhaust lobes. That is absolutely a waste of time on a 5,500 rpm truck engine. Go single pattern and tighten the LSA a bit. Most cam manufactures will spec you something around 204/214 or 206/212 or 212/218 on a 112 LSA. Something like a 206/206 on a 108 or 212/212 on a 110 will make more average torque. On Comp Cams HORRIBLE advice and recomendation, I have a 218/228 on a 108 in the 383 in my van currently. It is completely wrong for what I want myself. I have a custom grind Erson 219/219 on a 112 to replace it with that Lloyd Elliot and I conversed and decided on would be a much better fit. The Erson should have a nice smooth, near stock idle, pull low rpm without bucking and surging and deliver better mileage. The Comp Cam has too much overlap and the IVC is too early making it octane sensitive and it has a misfire induced shudder under 1,500 rpm when it is under load. I end up cruising around with an unlocked torque converter under 50-60 mph because of it.

L31Max I’ve seen some of your threads and replies on here and was hoping you’d reply with some info.
I was wondering about single vs dual pattern and read a couple motor trend articles about it on a couple their 350 builds and a single pattern seems to work better, although I’ve read some other articles saying the opposite.
I was looking at a cam not long ago from Howards that is a single pattern, but can’t remember the specs. Now if I was to go with something around a 219 duration like you mentioned, but with a 110 lsa would that be too much for the factory converter? Would like something in that would give it a little bit of a lopey idle.

 

[L31MaxExpress]

L31Max I’ve seen some of your threads and replies on here and was hoping you’d reply with some info.
I was wondering about single vs dual pattern and read a couple motor trend articles about it on a couple their 350 builds and a single pattern seems to work better, although I’ve read some other articles saying the opposite.
I was looking at a cam not long ago from Howards that is a single pattern, but can’t remember the specs. Now if I was to go with something around a 219 duration like you mentioned, but with a 110 lsa would that be too much for the factory converter? Would like something in that would give it a little bit of a lopey idle.

Well this might answer your question. I do not like the stock torque converter with the stock camshaft. If the transmission comes out it atleast gets a factory 4.3 W converter for that year model transmission that has the 2025 rpm K-factor. It stalls about 2,500-2,800 behind a V8. The converter makes more of a difference than a mild cam does.

 

[Komet]

I was wondering about single vs dual pattern and read a couple motor trend articles about it on a couple their 350 builds and a single pattern seems to work better, although I’ve read some other articles saying the opposite.
I was looking at a cam not long ago from Howards that is a single pattern, but can’t remember the specs. Now if I was to go with something around a 219 duration like you mentioned, but with a 110 lsa would that be too much for the factory converter? Would like something in that would give it a little bit of a lopey idle.

More duration on the exhaust tends to favor higher rpm HP production, and will give gains when the exhaust is a choke point but a lot of builds are targeted towards high rpm street/strip cars where you want that kind of action.

The single pattern tends to favor torque production down low where trucks want it. I'm sure there's a head and exhaust combo that contradicts these tendencies, how well your specific heads flow on the intake vs exhaust is a factor. In general I think you'll do well with a cam under 220ish @ .050 and 110-112 LSA.

 

[GMCBurb99]

Are you running headers on this?

Are you running headers on this?

Just seen your question and yes I’m running shorties into 2.5” stainless catless pipes with bungs for the O2’s, then into dual magnaflow’s. Also I’ve put in a msd distributor, MPFI upgrade, and egr delete. Transmission has been gutted and rebuilt with all sonnax interals as well.