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  1. #1
    Fuel Injected!
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    As a quick pick, I'd expect something like the Comp Cams 08-423-8 to be a better cam.

  2. #2
    Fuel Injected! brian617's Avatar
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    Quote Originally Posted by lionelhutz View Post
    As a quick pick, I'd expect something like the Comp Cams 08-423-8 to be a better cam.
    Isn't the lobe sep a little tight for that much duration for good strong idle vacuum?
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
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  3. #3
    Fuel Injected! Engine07's Avatar
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    I was thinking that but I'm not familiar with tuning these things yet with mods lol. I know the cam I chose would def not be my choice if I was going carb or max power but I was thinking great torque, good power, and being done by 5500. Oh and being able to tune lol. I wouldn't mind stepping up a bit if I don't lose much torque and I'm still able to tune. As of now I'm looking at 454 tb with 454 injectors for fueling. I think around 670cfm should be plenty for this engine or do you recommend a bored out 454 tb?

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    Fuel Injected! Roadknee's Avatar
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    You won't need a lot of cam to meet your goals. Take a look at this 383 with Vortec heads.

    http://www.superchevy.com/how-to/578...e-engine-test/

    With the "Hot" cam

    http://www.superchevy.com/how-to/148...-engine-build/

    I think something in between the two would be ideal such as

    http://www.compcams.com/Company/CC/c...?csid=186&sb=2

    I'd run 1.6 rockers on the intake and 1.5 on the exhaust, and step up to the premium beehive springs and retainers. Even with the 110 lobe separation this cam would be compatible with your TBI.

    I think the larger comp cam Lionel mentioned would be challenging to tune with TBI. I have a TBI 383 with a 223/228@0.050" mild hydraulic flat tappet and it needs 13:1 afr at idle and less than 14.7 below 1,500 rpm to run well. I've tuned a port injected 406 SBC with a Lunati 219/227 efi hydraulic roller cam. It's on the edge of being able to run closed loop idle. It runs smoother at 13.5:1 idle, but can get by at 14.7:1. Port injected can handle more cam because fuel distribution is better.

  5. #5
    Fuel Injected! BLG355's Avatar
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    I am running an Isky 211252/257 cam. Ton's of bottom end and pulls hard through the top end too. it's a great all around cam for street use, specially in my heavy pickup. it will idles super smooth too. I run 1.6 rockers and I am very happy with it. I had my shift points as high as 5800, still pulled good but was pretty much done.

    http://iskycams.com/timingchart.php?...ber=210252/257
    My Build: 95 K1500, 355ci w/ OEM roller setup - zero decked, Eagle steel crank, Scat bushed H-beam rods, Speed Pro 2V flat top pistons - Rotating assembly balanced. Dart 165cc Iron Eagle S/S heads - 72cc chambers - 1.94 / 1.50 valves. Isky roller cam - 204/209 dur @ .050 - .480/.496 lift with Comp Magnum 1.6 rockers, Edelbrock 3704 intake - Bored to 52mm - 454 throttle body, Delco EP381 fuel pump @ 18 psi running through 80# 454 injectors. Hedman Headers into 3" Dynomax exhaust.

  6. #6
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    Quote Originally Posted by Roadknee View Post
    You won't need a lot of cam to meet your goals. Take a look at this 383 with Vortec heads.

    http://www.superchevy.com/how-to/578...e-engine-test/

    With the "Hot" cam

    http://www.superchevy.com/how-to/148...-engine-build/

    I think something in between the two would be ideal such as

    http://www.compcams.com/Company/CC/c...?csid=186&sb=2

    I'd run 1.6 rockers on the intake and 1.5 on the exhaust, and step up to the premium beehive springs and retainers. Even with the 110 lobe separation this cam would be compatible with your TBI.

    I think the larger comp cam Lionel mentioned would be challenging to tune with TBI. I have a TBI 383 with a 223/228@0.050" mild hydraulic flat tappet and it needs 13:1 afr at idle and less than 14.7 below 1,500 rpm to run well. I've tuned a port injected 406 SBC with a Lunati 219/227 efi hydraulic roller cam. It's on the edge of being able to run closed loop idle. It runs smoother at 13.5:1 idle, but can get by at 14.7:1. Port injected can handle more cam because fuel distribution is better.
    I had 232/240 @ .050 on a 110* LSA in a 10.5:1 Vortec head 383 with a highly modified TPI setup on it. Never had an issue getting it to idle in closed loop. Had to adjust the o2 windows and what not to get a clean idle, but it would run in closed loop at about 14:1 air/fuel ratio. The more overlap you have the lower your target o2 voltages need to be set to get the same air/fuel mixture.

  7. #7
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    I think Roadknee picked the better Comp cam. Your initial Lunati pick should be good too.

    You'd probably find the XR276HR is too much in the truck. I was suggesting that as a Hot cam replacement but looking again, I now think the XR270HR is a more comparable but better replacement for the Hot cam.

    Just to throw another cam out there. What does everyone think of the Comp 266HR-14? - http://www.compcams.com/Company/CC/c...?csid=213&sb=2
    Last edited by lionelhutz; 02-22-2015 at 12:41 AM.

  8. #8
    Fuel Injected! Roadknee's Avatar
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    Quote Originally Posted by lionelhutz View Post

    Just to throw another cam out there. What does everyone think of the Comp 266HR-14? - http://www.compcams.com/Company/CC/c...?csid=213&sb=2
    i think either of the comps, the lunati, and the hot would all work well. I like the shorter duration and tighter lsa of the comp for better low and mid range. Should pull strong well past 5k and have great drivability.

  9. #9
    Fuel Injected! Engine07's Avatar
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    I appreciate all of you guys help on here, especially with what can and can't be tuned. I'm thinking whenever I get the engine finished, having it dyno'd so we can put the results up here for what can be achieved with tbi vs carb and maybe coming up with a list for guys like me that aren't very familiar with tbi tuning such as what duration and lsa can be tuned on tbi vs the engine displacement that makes them seem smaller. I'll update with specs and pictures on the engine build too so anyone who searches and finds this in the future will have all the specs and final hp, tq, and driveability. Just got finished running the final pattern on my rear gears and getting it buttoned up so the shop is about to get cleaned in prep to start the engine. Crank and pistons should be here Wednesday!!

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