Summit or JEGS Vortec heads?

Slade88

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Hi everyone, so the heads I wanted to initially get for my truck were the summit heads (linked here)


These heads are out of stock and I’ve had them ordered since May!, it’s estimated they’ll ship in November and I don’t plan on waiting that long.

I found these new heads on jegs and am curious how they size up power wise.


I know the summit heads have more room for valve lift but I bought some Z28 springs that I could put on the jegs heads to give me some more lift, could I run a comp 480 magnum with the jegs heads? Thanks!
 

Hipster

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There's really not a whole lot of information on either but you're looking at stock replacement type heads that are going to be similar to stock performance levels so no magic is going to happen with either. Another couple hundred on heads you can get into 185cc runner heads.

Comp 280 can be a poor cam choice for quite a few reasons and is probably a bit much for Z28 springs. Different springs don't necessarily give you more retainer to guide clearance. It needs to be measured and verified along with coil bind. It's a case where the catalog is correct in saying more torque converter is needed also. A Comp270 with 1.6's, Rhoads lifters, low 220's at .050, 500 lift is much more streetable, and there are better choices than that these days.

You asked a couple questions without stating what your goals are, what the overall plan is, or what you're working with. Flat tappet block with Vortec heads?
 
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Hipster

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Didn't realize you were starting multiple threads about the same subject matter.

being a tbi engine there are better choices that make more sense than Vortec heads if purchasing a set. Alot of the cost savings of the cheap heads may be negated by what's required for induction.
 
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Erik the Awful

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Installing your TBI on a Vortec intake manifold will take a bit of trickery. There was a Vortec TBI manifold, but I think they're over $500. I put a Vortec square-bore carb manifold on top of my heads, put a square-to-spread-bore adapter on that, and then put a TBI adapter on top of that. Then I ditched the TBI and went with a Holley Sniper and was happier. The factory TBI can't support a big cam without some serious upgrades and re-tuning, and by the time you get the parts and tools to do that, you're near the cost of buying a Sniper.
 

Hipster

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Installing your TBI on a Vortec intake manifold will take a bit of trickery. There was a Vortec TBI manifold, but I think they're over $500. I put a Vortec square-bore carb manifold on top of my heads, put a square-to-spread-bore adapter on that, and then put a TBI adapter on top of that. Then I ditched the TBI and went with a Holley Sniper and was happier. The factory TBI can't support a big cam without some serious upgrades and re-tuning, and by the time you get the parts and tools to do that, you're near the cost of buying a Sniper.
yep
 

Slade88

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I’d like to get close to 400 HP. I already have a Vortec intake purchased and plan on ditching tbi for a 4 barrel carb. I’m just curious how much bang for my buck I’ll get with these heads and how much of an improvement they’ll be over the TBI heads already on the truck.

I want a big lopey cam as well, would a comp flat profile 270 be a good choice? It says it can handle .475, 470 should be fine I’d imagine?

I will take a look at those profilers if you really think they are worth it
 

The_Family_Tahoe

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I've run the comp 280 a couple of times, the reality is there are better cams on the market today. The magnum line of cams is dated. It's been proven multiple times over the push rod motors need more exhaust duration (magnum cams have intake duration=exhaust duration), and flat tapped camshafts are old tech. I dont think the OEMs have mass produced a flat tappet since the f150 in 1994. Flat tappets have their place, but power under the curve, driveability, and reliability are better with a hydraulic roller vs a flat tappet. A given combination can make the same or more power with a roller camshaft using 10-15 degrees less duration than a flat tappet. This means with good springs a 215 degree intake duration roller will compete with an old school flat tapped cam with 230 degrees intake duration. The roller option gives a smoother idle, more off idle power, more total power, and more reliability using off-the-shelf oil.

All the components in the build need to work together. It's more fun to drive a stock motor around town stoplight-to-stoplight with a mild stall and 4.11 gears than a built 350 with a stock torque converter and 2.73 gears. The second scenario will make more numbers on a dyno but will be an absolute dog between stoplights relative to the first example which will be more responsive to throttle input. If you're looking for performance and driveability the combination needs more gear and converter in either scenario.
 

L31MaxExpress

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I've run the comp 280 a couple of times, the reality is there are better cams on the market today. The magnum line of cams is dated. It's been proven multiple times over the push rod motors need more exhaust duration (magnum cams have intake duration=exhaust duration), and flat tapped camshafts are old tech. I dont think the OEMs have mass produced a flat tappet since the f150 in 1994. Flat tappets have their place, but power under the curve, driveability, and reliability are better with a hydraulic roller vs a flat tappet. A given combination can make the same or more power with a roller camshaft using 10-15 degrees less duration than a flat tappet. This means with good springs a 215 degree intake duration roller will compete with an old school flat tapped cam with 230 degrees intake duration. The roller option gives a smoother idle, more off idle power, more total power, and more reliability using off-the-shelf oil.

All the components in the build need to work together. It's more fun to drive a stock motor around town stoplight-to-stoplight with a mild stall and 4.11 gears than a built 350 with a stock torque converter and 2.73 gears. The second scenario will make more numbers on a dyno but will be an absolute dog between stoplights relative to the first example which will be more responsive to throttle input. If you're looking for performance and driveability the combination needs more gear and converter in either scenario.
I personally would not run any newer cam lobes for a street engine. My 383 has Magnum High Lift Roller lobes and no shortage of power. Also dual pattern cams are a crutch, single patterns often perform better.

Flat tappets are alive and well in almost every DOHC engine.

My mom's 2019 Titan has a flat tappet kind of valvetrain with actual clearence specs.

The 2011 Pathfinder and 2007 G35 sedan have the same style valvetrain. An offset lifter bucket rides directly on the cam lobe, spinning the bucket that rotates on top of and pushes on the valve tip.

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These sit under the cam lobes, on top of the valve tips. Springs, Retainers, and Locks sit under them.

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The_Family_Tahoe

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I personally would not run any newer cam lobes for a street engine. My 383 has Magnum High Lift Roller lobes and no shortage of power. Also dual pattern cams are a crutch, single patterns often perform better.

Flat tappets are alive and well in almost every DOHC
Dual pattern cams are a crutch. Is there an example you can share of a single patter cam performing better than a dual pattern cam with the same intake lobe? I'm thinking about this from an intake lobe point of view, where the intake lobe is static between the two comparisons.
 
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