How to get a 5.0L to spin to 7k RPM?

Nobody · Apr 3, 2006

I think this is expensive territory but since I am putting 4.10 gears in, I would like to consider the idea of spinning the motor to 7k. What parts (metal and electronic) does it take to do this with a reasonable level of reliability? How much of the stock motor can you keep to do this?

Thanks,
Gabe

Zero Signal · Apr 3, 2006

Safely AND make power? A $2000+ valve train setup, 331 long rod, heads that flow 250+ int/exh, and a full aftermarket ECU.

The Green GT · Apr 3, 2006

Just keep your foot on the gas and hope it holds.

No.. wait... thats a BAD idea.

Nobody · Apr 3, 2006

So why can't the 5.0L rev that high? Why is a long rod 331 the weapon of choice? Don't you want a shorter stroke to rev?

Zero Signal · Apr 3, 2006

You want to keep your piston speed down, so the long rod will do that. The inherit problem with wanting to rev that high is our valve train. For every hundred rpm, the required spring seat and open force increases at an increasing rate. So when you get up to 7k, it gets more and more expensive to support it. You're getting into a territory where the combination of a heavy spring and high rpms will bleed your lifters like crazy. BUT if you have the money, then it's not an issue.

Nobody · Apr 3, 2006

Wow those Mod Cobra motors are built pretty well then. So what is the realistic upper limit for the 5.0L?

blksn955.o · Apr 3, 2006

you fogot aftermarket block as the rpm plus a good stroker will be a killer.

most stroker kits (I have never seen one but one may be out there) come with a 5.40 rod or whatever compared to our 5.090 rod so they will be "long rod" already for the most part.

its sounds cool but you realy wont have any streetability out of it. I would just try to build a combo that works up to the stock 6250 rev. limit or just under it at say 5,800-6k.

Nobody · Apr 3, 2006

Awe man what a piece of junk our motors are!!

Just Kidding. So all the HCI cars are making their 300rwhp under 6k rpm? What's the realistic hp numbers for a smog legal $6-8k 374?

final5-0 · Apr 3, 2006

Everything that has been said is true
but
The 5.0 valve train is so heavy with those big ole roller lifters

By the time you spring it up and all that other stuff .........
you've done what you said you did not want to do.

Gone beyond simple and cost effective

Grady

final5-0 · Apr 3, 2006

Nobody said:
So all the HCI cars are making their 300rwhp under 6k rpm? What's the realistic hp numbers for a smog legal $6-8k 374?

I would say that is not necessarily so

I have no reservations of taking my combo to 6K
and
From time to time it sees 6100 to 6200.

At 6K, I'm still pulling hard, so those instances are not intended but an occasional slight over rev does not make me loose any sleep at night

I would think most other peeps would have a similar feeling
but
I guess we can wait and see

Grady

Nobody · Apr 3, 2006

final5-0 said:
I would say that is not necessarily so

I have no reservations of taking my combo to 6K
and
From time to time it sees 6100 to 6200.

At 6K, I'm still pulling hard, so those instances are not intended but an occasional slight over rev does not make me loose any sleep at night

I would think most other peeps would have a similar feeling
but
I guess we can wait and see

Grady

So are you saying that the dyno sheets of the HCI combos are usually going uphill all the way to 6k? I don't look at a lot of N/A dyno sheets so I have no idea. Help me out here guys.

zenboy99 · Apr 3, 2006

I think you guys are really uneducated about the Pure Street combo's that are running in the NMRA on hydraulic lifters. Some guys have told me that they're turning over 8,000 rpm. If you don't believe me, go to a race and talk to them.

Last year I was 90% sure I was going to build a pure street combo, but....I bought a house (damn spouses). I really looked into this issue, and it really made me wonder why aren't we all reving our 302's higher? All my friends BMW's and Honda's have hardly nothing in low-end torque compared to my car.

I think the issue, from what I've been told, is high rpm on a stock block. But going NA on a 302 with a 7k redline shouldn't be a problem, many guys in the NMRA have been doing it.

Its not nearly as expensive as you think. Shoot Ed Curtis at FTI an e-mail and he can lay out a combo for you. Troy Carters stock 302 bottom end was reving pretty high, he was running mid 11's and drove the car to the track. I know because I saw it run many times.

These are just observations that I've made.

wytstang · Apr 3, 2006

As long as your valvetrain is up to the task there really isn't a problem taking it up to 7k. The only thing you will have to do is "if" you see 7k often is check your valve lash periodiclly(sp?) to keep everything on par. Also match your induction and exhaust to handle the volume of air coming in/out.

final5-0 · Apr 4, 2006

You are not gonna get to the kinds or rpms you guys are talking about and stay within Gabe's intent in his original post.

then again

Maybe I'm staying too basic with my understanding of his question.

I am sure there is nothing inexpensive about a Pure Street combo.

As for a stock block, iron headed combo, which is the most inexpensive way to go and what he now has .............

Even if you only beefed up the spring pressure to turn 7k, you are not gonna be all that reliable as that pressure will put quicker wear and tear on everything

I'm not saying you can't turn the rpm

just not in an inexpensive, reliable way

Grady

Joes95GT · Apr 4, 2006

Revving to 7k RPM ain't nothin' if you've got the scratch to do it.

You need:
1) A less aggressive, more "square" cam lobe, compared to most OTS street cams.
2) A factory set of Ford lifters will work just fine.
3) Light(er)weight, expensive springs with tons of open pressure.
4) Titanium retainers.

Cylinder head flow doesn't make a bit of difference in making power in the higher RPM - it's all in the cam timing. If you REALLY wanted to, you could zing a set of E7's to 7000 RPM in unported form.

You don't need long rods to make anything work. A BBC can turn to 7k if set up properly and they have a rod ratio into the high 1.4's or low 1.5's.

302 motors are built to rev. Replace the rod bolts and everything else will spin if its set up properly.

Joe

Pokageek · Apr 4, 2006

final5-0 said:
I would say that is not necessarily so

I have no reservations of taking my combo to 6K
and
From time to time it sees 6100 to 6200.

At 6K, I'm still pulling hard, so those instances are not intended but an occasional slight over rev does not make me loose any sleep at night

I would think most other peeps would have a similar feeling
but
I guess we can wait and see

Grady

Hang on..somebody said that I am pegging my stock MAF at higher RPM. Grady aren't you running a stock MAF?

final5-0 · Apr 4, 2006

Pokageek said:
Hang on..somebody said that I am pegging my stock MAF at higher RPM. Grady aren't you running a stock MAF?

No Sir

I moved up to a ProM 80 a good while back

Grady

5spd GT · Apr 4, 2006

To go along with Joe's post and you want to spend a bit more and are able. Get a lightweight rotating assembly along with a good balance and balancer.

BlackVert · Apr 4, 2006

Joes95GT said:
Revving to 7k RPM ain't nothin' if you've got the scratch to do it.

You need:
1) A less aggressive, more "square" cam lobe, compared to most OTS street cams.
2) A factory set of Ford lifters will work just fine.
3) Light(er)weight, expensive springs with tons of open pressure.
4) Titanium retainers.

Cylinder head flow doesn't make a bit of difference in making power in the higher RPM - it's all in the cam timing. If you REALLY wanted to, you could zing a set of E7's to 7000 RPM in unported form.

You don't need long rods to make anything work. A BBC can turn to 7k if set up properly and they have a rod ratio into the high 1.4's or low 1.5's.

302 motors are built to rev. Replace the rod bolts and everything else will spin if its set up properly.

Joe

subscribing because my goal is also to spin to 7000 someday.

i will definately want to to with the lightest rotating assembly i can afford.

would a 306 be easier to spin to 7000 than a 331 because of the shorter distance the pistons are moving?

joe, what springs do you have in mind here?

blksn955.o · Apr 4, 2006

Joes95GT said:
Revving to 7k RPM ain't nothin' if you've got the scratch to do it.

You need:
1) A less aggressive, more "square" cam lobe, compared to most OTS street cams.
2) A factory set of Ford lifters will work just fine.
3) Light(er)weight, expensive springs with tons of open pressure.
4) Titanium retainers.

Cylinder head flow doesn't make a bit of difference in making power in the higher RPM - it's all in the cam timing. If you REALLY wanted to, you could zing a set of E7's to 7000 RPM in unported form.

You don't need long rods to make anything work. A BBC can turn to 7k if set up properly and they have a rod ratio into the high 1.4's or low 1.5's.

302 motors are built to rev. Replace the rod bolts and everything else will spin if its set up properly.

Joe

like you said its gonna need scratch to do.

A buddy of mine has a B.O.P. 400 with stiegy (apten blower guy)ported ram air III heads and a custom ultradyne cam. His problem is that the combo can make power at the 7k mark but the BIG B.O.P stuff (I would think the BBC would be close) is also REALY friggan heavy and he stops around 5800-6k. I has since put on a 160 shot on cast pistons to try and melt the moter to give him a reason to build a lightweight alum. headed turbo setup...the rotating assembly is not cheap like 8k for the crank alone.

yes bitchin about rod ratio has been posted about alot on harcore with the end result being very low on the "list" as far as what it will do in reality.

How to get a 5.0L to spin to 7k RPM?

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