Cam selection for 383

[JeremyNH]

Another cam thread. I have a short block SBC bored .040 over with a 3.8" stroker crank so technically 390, 9.6:1 CR. Going into a 1998 K1500 when build is complete (will be a while, late next year most likely). I haven't yet purchased the heads but it will have AFR 912s (aluminum, high flowing, 65cc chamber, 190cc runners). Existing motor is a very well running 5.7L stock heads, marine cam, marine intake, coil-per-cylinder, Gibson shorties to 2.5" headpipes to Magnaflow muffler, single 3.5" tailpipe. 4L80e transmission.

I'll be transferring over the ignition, intake, and exhaust, likely uprating the injectors from the current 27# at FP to 42# at FP.

I am looking for DD drivability without leaving anything on the table. It's not a DD, just a project truck with sentimental value (was my dads', bought new in 98 and came to me by inheritance 4 years ago, 123k miles). I contacted Comp, Lunati, and Howards by filling out their "recommend a cam" pages. Only Howard responded. I spoke with Comp back when I was looking for a cam (settled on the 395 due to cost/availability) and have their recommendation then which I wouldn't expect to change for the build since my aims are unchanged.

With respect to the wide experience of folks on the forum I would like to keep it to just these three cams. I understand there is a legion of awesome lobes out there but these cams all have a fair volume of feedback/write-ups and getting a "go with this" recommendation on something with sparse or no reviews or articles isn't helpful because it won't be pursued. Thanks.

Howards recommendation (seems more like a car cam but positive reviews - in cars):
183215-14
Lift: 0.495/0.500
[email protected]: 217/225
ICL: 110
LSA: 114
RPM: 1300-5500

Comp Cams kinda recommendation (leaning towards, positive reviews entirely in trucks)
08-500-8
Lift: 0.480/0.488
[email protected]: 206/212
ICL: 106
LSA: 112
RPM: 1000-5000

Lunati in-the-blind (good reviews, cars and trucks, bit concerned about the power band being too high but all Lunati power bands look high)
20080720 (Voodoo but it looks to have been High Eff EFI prior to that under part #60120)
Lift: 0.507/0.515
[email protected]: 211/219
ICL: 106
LSA: 112
RPM: 1600-5600

 

[homeslice]

I"m running the 08-501-8 in '98K2500 5.7L with 24x igntion, 0411, roller rockers, upgraded comp 26918 springs, and BBK TB. The 08-500-8 was not in stock when I purchased, so went a hair bigger with the 501 which was in stock at the time. Can tell you I'm still working with BB on dialing in the tune for cold startup, but idle is smooth and quiet; and all around power is very good. I would not be afraid to install in the larger 390ci, especially with AFR heads. btw, you helped me get my injector wiring corrected during my 24x conversion - thanks again.

 

[L31MaxExpress]

Mine is 218/228 @ 0.050, 108 LSA and degreed in at a 106 ICL. Rhoads V-Max lifters. It is fairly smooth with a bit of chop at 600 rpm and dead smooth at 750. I run 1.7 rockers, the lift comes out at 0.578 on both sides.

 

[JeremyNH]

I"m running the 08-501-8 in '98K2500 5.7L with 24x igntion, 0411, roller rockers, upgraded comp 26918 springs, and BBK TB. The 08-500-8 was not in stock when I purchased, so went a hair bigger with the 501 which was in stock at the time. Can tell you I'm still working with BB on dialing in the tune for cold startup, but idle is smooth and quiet; and all around power is very good. I would not be afraid to install in the larger 390ci, especially with AFR heads. btw, you helped me get my injector wiring corrected during my 24x conversion - thanks again.

Well nothing is in stock anymore but I don't mind placing an order for delivery a few months out given that my time horizon is so far out. I know the 501 - a little more lift, a little more duration, and a 108 ICL. I think the latter part is why they say TPI since they are anticipating a more difficult computer to tune. 106 is supposedly more modern but I'm not an expert. Probably overthinking this. But I am pretty sure the Howards is for cars 110/114 ICL/LSA doesn't conform with torquey cams so probably the closest thing they have for a truck cam but not really meant for heavy vehicles. Acceptable but not purpose built.

 

[JeremyNH]

Mine is 218/228 @ 0.050, 108 LSA and degreed in at a 106 ICL. Rhoads V-Max lifters. It is fairly smooth with a bit of chop at 600 rpm and dead smooth at 750. I run 1.7 rockers, the lift comes out at 0.578 on both sides.

Thanks for the input. Duration is more than I thought would be comfortable with that LSA/ICL but looks like I'm a bit off on that. I won't be going with that much lift. I believe you use Etec 170s which like more lift but the AFR 912s see virtually no gain beyond .500 so want to keep it below .525. My rotating assembly uses the Eagle clearanced 6.00 H beams so I shouldn't have too much issue with cam clearance but why push it to no gain is my thinking. What's your TC stall? My 4L80e is stock at 1800 which is something to consider. I really don't care about revs beyond 5000 so peak HP is just a paper number to me. I'm looking for high torque and a flat curve well into the 4s. That's what I have in mind by "drivability".

 

[L31MaxExpress]

Thanks for the input. Duration is more than I thought would be comfortable with that LSA/ICL but looks like I'm a bit off on that. I won't be going with that much lift. I believe you use Etec 170s which like more lift but the AFR 912s see virtually no gain beyond .500 so want to keep it below .525. My rotating assembly uses the Eagle clearanced 6.00 H beams so I shouldn't have too much issue with cam clearance but why push it to no gain is my thinking. What's your TC stall? My 4L80e is stock at 1800 which is something to consider. I really don't care about revs beyond 5000 so peak HP is just a paper number to me. I'm looking for high torque and a flat curve well into the 4s. That's what I have in mind by "drivability".

I had Etec170s. I have Assault castings that were ported by Lloyd Elliot. 215cc roughly and nearly 300 cfm at 0.600. My stock 80E converter stalled nearly 2,300 behind my old 350. The one I had built for the 383 is about 2,800. Tighter LSA closes the intake valve sooner, trapping more cylinder pressure, giving more torque. I am also at 11:1 compression with 6" rods.

 

[L31MaxExpress]

My buddy had a 6" rod 200cc skip white head 383 in his 98 K1500 mud truck with a SAS swap. He ran a Comp 08-412-8. Nice running little cam. His truck had a built 4L60E, 4.10s and 44s. We can all guess what part of the driveline decided the 383 had too many beans.

 

[Erik the Awful]

I'm running the Lunati 20080720 in my truck. The Vortec fuel injection system with MPFI in my '99 Suburban handled the cam okay, but needed a tune. When I swapped the engine into my '89 Stepside, the TBI couldn't handle it. I'm running a Holley Sniper on it now.

When I ordered the cam, I initially ordered a different cam that was a complete mismatch. I realized it and in a panic called Lunati's tech line direct. The dude on the other end spec'ed this cam. It is very much a truck cam, and it won't disappoint. It really makes me wish I'd done some serious porting on my Vortec heads.

 

[L31MaxExpress]

Thanks for the input. Duration is more than I thought would be comfortable with that LSA/ICL but looks like I'm a bit off on that. I won't be going with that much lift. I believe you use Etec 170s which like more lift but the AFR 912s see virtually no gain beyond .500 so want to keep it below .525. My rotating assembly uses the Eagle clearanced 6.00 H beams so I shouldn't have too much issue with cam clearance but why push it to no gain is my thinking. What's your TC stall? My 4L80e is stock at 1800 which is something to consider. I really don't care about revs beyond 5000 so peak HP is just a paper number to me. I'm looking for high torque and a flat curve well into the 4s. That's what I have in mind by "drivability".

Just thought I would throw up a mew exhaust clip of that cam idling with a new quiet exhaust system. Really hard to tell it has anything but the stock cam.

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