I cannot recommend Crower custom designed solid rollers with more enthusiasm They need the flow numbers on the heads from .100 - .700 in .100 increments - provide with gear ratios car weight etc and you will be VERY HAPPY.
I had a .020 over 302 in my 69 Z with 12.5/1 compression, the cam was a .636 gross lift with 278in 282exh duration- BRUTAL out of the hole and easy to drive PLUS made 15" vacuum at 1000rpm idle.

 

What is the Crower part number, I couldn't figure out which cam might be yours online.

 

The issue with hyd lifters collapsing at RPM is the bleed down rate under the pressure they’re being exposed to (when more oil is being forced out than can be forced in given the time available at rpm the lifter collapses). Higher quality lifters that have tighter tolerances allow for lower bleed down rates which means more ability to resist bleeding down faster than the fill rate.

Higher pressure springs, more aggressive cam lobes (accel rate), heavier valve trains (especially on the valve side), and more RPM exposes the lifter plungers and internal oil to more pressure which bleeds them down sooner.

The LS beehive springs mean smaller and lighter retainers AND lower spring PSI requirements. Those hollow stem intakes and thin valve stems also help and are a part of the LS, high rpm capable hyd roller “recipe” but good lifters are critical.

I was told that if I went with beehive springs on my cam I could get away with a spring rate 340lbs / inch or I’d need double springs with 433 lbs per inch to control the valve; the total weight of the beehive spring and retainers and keepers was considerably less and about 100# less open pressure all means considerably less pressure on those hyd lifter plungers/ oil chambers. -Beehive springs are attacking the “dynamic pressure on the lifter plungers” problem from two different approaches simultaneously- they’re reducing the valve train weight AND reducing spring pressures.

(They also reduce the spring harmonics, but not as much as the fancy fully conical springs.)


Adam

 

What I learned over decades of performance combustion is that for anything other than a true all out race car, I want the lightest spring possible, the lowest lift, and the slowest ramp rate on the lobe of the camshaft. This is how we can preserve the valvetrain reliability, control the valve well at high rpm.

It doesn't take big lift or powerful springs to make power. For example I am using a PAC-1218 valve spring and a cam with .520 to .550 lift ranges using a turbocharger and the slowest ramp cam lobe I can find. A turbo makes an engine more reliable as high exhaust gas pressure protects the rod cap/rod bolts allowing the engine to make serious power up top with factory bolts and rod hardware without damaging the engine bearings or pulling apart the connecting rod.

Here is TFS-30602001 which is a very slow ramp camshaft and fairly low lift couple summers ago on a 200,000 miles 5.3L w/ 4l80e


14psi of boost using 93 octane gasoline, no meth no E85. Just back to back dyno runs in the Florida summer heat, it was the hottest day possible.
5.3L free(low cost engine) from any junkyard with Stock lifters, stock pushrods, stock head, stock piston/rod/etc... Didn't open the bottom end. I put 40,000 miles on it since 2017 still driving it, reaching 220k miles this year total on the motor.
The high mileage helps the engine handle the power, everything is a bit looser and the compression is down a bit making it safe to spin and boost
I bet its close to 620rwhp now, I doubled the injectors since 2020 so I can raise the boost to max the turbo out. I am planning a return to the dyno, perhaps July again 2022 to see the difference.

Good results with a cheap engine from 2002 with 200,000 miles can be extremely reliable and make significant power using a small cam and light spring, gasoline.
It seems crazy to push the limits of cam and spring- using lift specc'd out to generate power is unnecessary if we are shooting for just 500 to 1000hp. What you really want is the turbocharger and a very low lift, a lazy cam. Hyd or solid roller, either will work great, just keep the lift down mainly. This way you can drive the engine like a normal car and it will last like a normal car and make decent power. And as a bonus, the engine is disposable, no investment, no problems no matter what happens to it.

 

Different build mentality all together, no doubt it works.
Tried all the fast ramp stuff with FT and roller cams its just not worth it.
Losing valve control esp at higher rpm is a recipe for expensive noises, shortened valvetrain life etc.

Talon...on an engine that may have a worn bore do you find theres a point where xx amount of boost slips by the rings and causes issues wtih crankcase pressure? (Never built a turbo car)
Seeing more and more guys putting them on Gen 1 engines, even big blocks. Chevelle forum has a few examples my god do they make crazy power.

 

Funny you should ask. I post on multiple forums about controlling crankcase pressure. It is a constant discussion topic, and honestly- I feel that PCV is the most important aspect of combustion engine tuning. It must be carefully controlled because of it's influence on engine health and lifespan. To answer your question in a short sentence: There is no issue with crankcase pressure when using the correct PCV setup for a turbo engine. I model my PCV after the famous Skyline/Supra engines. Crankcase pressure is a set number, like fuel pressure or oil pressure. You monitor the pressure, then adjust as needed.

Here is a write up which can be applied to any engine. The key is to monitor crankcase pressure and adjust as needed.
https://www.supraforums.com/threads/.../post-13980010

another with the same question and more details above and below
https://www.supraforums.com/threads/.../post-13987501

A GM powertrain engineer approval and additional details above
https://www.thirdgen.org/forums/powe...ml#post6466928

This is my 'short list' of how you can maintain a reliable high output stock LS engine up to 1200rwhp
https://www.corvetteforum.com/forums...post1605161725

Tuning the engine for fuel economy
https://forum.hptuners.com/showthrea...l=1#post686802

More details about my setup and how to care for the engine
https://www.theturboforums.com/threa...ynojet.387535/

 

Wow...lots of good reading.
Cant imagine running over 1k to the ground.
Driven a few TT cars that were in the 6-700rwhp range you couldnt get into the throttle unless you were in a higher gear and eased into it. Id be in a casket too soon with that much.
Ca is the wrong place to do higher speed runs, fwy pulls...0-120 and back is good enough for me.

 

Hah well. We get used to it after a while and it starts to feel normal again. Although I will say I've been pretty damn happy with 500 where it is for the last couple years, basically able to spin the tires anytime is a pleasure not a curse when your objective isn't top speed and winning races, power number alone doesn't matter, its just for having fun and at 3000lbs fun starts around 500rwhp once we have to spend extra $$ for reduced economy compared to a 2 or 3L turbo engine which can 500rwhp with 30mpg easier. 1000 is a bit much unnecessary with normal tires which is all I could ever afford to use anyways. $90 rear tires that last 2 or 3 years - It's a daily not a race car. Basic transportation with a spice flavor. What more can I ask for as a homeless person using garbage to make 500rhp? Only reason I would push my garbage/junkyard setup to a limit is for science, I do love experiments and collecting data, especially when its affordable for college students. If we actually want to drive a car we love without worrying too much about the engine then near stock lifts with long durations plus turbocharger is a vetted option for any engine. There is somebody on youtube called 'sloppy mechanics' who has hundreds of dyno videos showing turbo V8, but at 3000-3800lbs vehicle honestly I've seen the 3L sufficiently move a Toyota Supra enough to say displacement isn't a factor when selecting the engine, choose the most reliable engine not the largest displacement. 4.8L > 5.3L Don't be afraid to build a 287 or 327 SBC instead of 383 all the time. Let every machine shop squeeze every drop of life from every SBC , at least let them try to save it, just remember to add the turbo and control PCV properly and go with the most reliable components, an SBC won't leak because of the details I posted above its all about crankcase pressure monitoring, put a 1-bar map sensor on it and dial down, I was pulling SBC since 16 years old, before youtube was invented in 1996 taking videos I was already header fingers hands ruined from modding SBC college drop out focusing solely on the car to become a mechanic and fast car builder. The only thing I learned from 20 years of doing this that nobody else seems to want to share is crankcase pressure monitoring, for some reason it has become esoteric. And I will probably stop posting about it shortly because I think I overdid it and broke the internet in a few places already. Maybe its something people have to come to over time on their own to grow as diagnosticians. At least now I am getting questions about blow-by, many people are learning but there are so many people the only way to make an idea become well known is when everybody sees it at once.... Did I ever tell you guys I'm really just an actor playing a role here? I'm just fulfill some roles better than the actual mechanic/programmer. Acting is more accurate than the real thing when I write more efficient code. I'm getting tired of the word efficiency.

The numerically lower gear ratios and large diameter tires can make torque manageable. Boost control ramping in properly and exhaust flow control is another helpful aspect. For example with the cutout closed high exhaust gas pressure slows the spool of the turbo, making it manageable and gradual with regular tires. If using slicks and racing, open the cutout, rapid spool the turbo is fine. The best part about turbo is the power is an adjustable dial in the glove box, more or less power is the turn of a ****. It can manage any situation. Many modern ECU even the gen3 like mine have torque management which is able to pull torque/timing for shifts so the car doesn't get sideways and try to run off the road like I've seen so many do with powerful transmission shifting. It is by far my favorite feature.

 

IT was custom designed by Dave Crower. I have the card somewhere around.
THE LSA was 112 and the ramps let the valve touch the seats VERY slowly so as not to pound the original seats into the heads.