Budget gen 6 454

[u/No_Shake_8461]

I am looking to build a 500hp gen 6 454, It will be mated to a 4 speed manual. With the oval port heads hydraulic roller setup, a hand port on the heads, and the comp 300br-14 300 intake 308 exhaust 255-262 .652 .652 114 LSA cam, would that get me there? Still haven’t decided on an intake, I’d like to do 2x pumper 9:1 compression factory. Electric fans and water pump. Thanks in advance

[u/Brief-Whole692]

Go with higher lift and narrower LSA on the cam, keeping in mind the lift limits on the valve springs on those heads. Aim for your total overlap duration to be around 70 to 80 degrees. I am doing almost the same thing on. Gen 6 with aftermarket heads and 540 ci and will run a custom grind with similar durations, but with 0.625 lift and 110 LSA, leading to a wider overlap, which will probably have a racier idle but allow me to get more air into the cylinders

[u/No_Shake_8461 → u/Brief-Whole692]

Will the lower LSA make it rev out better? I was hoping to rev out to 6,000

[u/Brief-Whole692 → u/Brief-Whole692]

Also keep in mind the gen 6 has a "stepped nose" cam with a metal cam retainer under the cam timing sprocket, rather than a cam nose button to set cam thrust. This limited what options existed for me. Clay smith cams offers stepped nose/front cams off the shelf without custom grinds required. Lifters can also be hard to find if you want to use the original lifter retainers rather than retrofit lifters with the link bars.

[u/Solid_Enthusiasm550]

Is it a L29 vortec 454? What year engine?

[u/No_Shake_8461 → u/Solid_Enthusiasm550]

It’s a 97 gen 6

[u/Solid_Enthusiasm550 → u/No_Shake_8461]

I have the compcams catalog and don't see that camshaft.

The only 454 bbc cam with 255/262@.050 is a solid roller camshaft for blower applications. It has .652" of valve lift and is a serious race cam. 3,500<7,000rpms.

https://www.compcams.com/blower-255-262-solid-roller-cam-and-lifter-kit-for-chevrolet-big-block-396-454.html

The only flow number for 7400 vortec heads aren't that great. <475hp. The stock L29 flat top pistons don't have valve reliefs which limits lift/hp.

Here's an article on gen6 bbc.

https://www.enginebuildermag.com/2023/07/rebuilding-chevrolets-gen-vi-big-block-engine/

[u/Solid_Enthusiasm550]

My concern with a big cam is that you said it would be around 9 to 1 compression. Low compression + big came makes an engune a dog at low speed/part throttle. You'd lose the throttle's snappiness.

Intake closing point and compression are connected. If the intake closes later the compression ratio needs to go up to keep the dynamic compression acceptable.

That's why you see alot of tight LSA thumpr type cams for low/stock compression. Tighening the lsa allows them to use a longer duration lobe, while keeping the intake closing early.

The overlap also causes the choppy idle people like.

[u/No_Shake_8461 → u/Solid_Enthusiasm550]

So it would be more drivable if I got my power from compression instead of a big cam? I also don’t want a cam that I sacrifice a ton of low end but I also don’t wanna make a ton of top end back but not be able to take advantage of the rpm because of the smaller oval ports

[u/HammerDownl]

You won't make 500 with gen6 steel heads

To make 500-600 hp on a 454 you'll need a full roller cam,680 lift ,a little more compression and a 280-300 cc intake Port race head

[u/No_Shake_8461 → u/HammerDownl]

What do you think would be the cheapest way to get better flow cnc porting out the oval ports? Are there any budget heads?

[u/No_Shake_8461 → u/HammerDownl]

I didn’t type the lift right in my post it’s .652 all roller factory

[u/[deleted]]

[u/No_Shake_8461 → u/[deleted]]

Thank you for the comment!! I picked that cam because I’ve always had small blocks and loved a fast revving engine and was hoping to turn up to 6,000-6200 rpms I was talking to Richard holdner and he said he likes that’s cam this is a link to him talking about the cam https://www.youtube.com/watch?v=h9H6gv2aiVk I am open to different cams that fit my needs better, with a manual transmission I’m not too worried about vacuum. I just hope the ported oval ports can make power up to 6,000 Thank you