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

[mootang]

I pressed the skinny pedal on the right and that seemed to do the trick

 

[Black95GTS]

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?

Not easier, more safe. The pistons move faster in the a stroker motor, because you have increased their stroke. So you have given them more distance to travel, and less time to do it in, so therefor they have to speed up accordingly.

The lower your piston speed, the lower fatigue is experienced in your engine.

In terms of springs, what kind of heads are you running? You'd probly be looking at something like 140 closed and 380 open.

Joe, you think he needs Titanium? Isn't that more of a 8000 plus rpm thing?

Adam

 

[WhiteDevil]

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

RPM doesnt matter when pegging a MAF its how much air is passing through it. If you had a bad set up i bet you could rev to 7k and not peg a MAF. I still have my Pro-M 80mm calibrated for 19#s and im juuuust peggin it at around 5,800rpm. Im gonna get it recalibrated soon, i hope.

 

[Grn92LX]

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

I'm pretty much with my buddy Joe here.

I spin my junk to around 6,700. What I did to my engine to do so was a GOOD valve spring package from FTI (ps 3 springs with installed height set), probe ultralight I beam rods with arp 7/16" cap screws (not 3/8" like typical) an aluminum flywheel and a romac light weight balancer with a 28oz balance. If I could change anything I would have done titanium retainers and 7/16" rocker studs. 7000 rpm would be nothing for my shortblock but i'm not sure if there would be too much useable power there. If I had a 302/306, this combo would need to be shifted around 7200-7300 rpm. Cam timing plays a big role like Joe said.

Don't forget a good clutch set up to shift at higher rpm's. My clutch is modified to be shifted at high rpm's w/o worrying about negative centrifugal vacuum.

 

[gustang818]

How about a non-roller 302 with a solid cam, a good set of heads and a carb? Back in the 70's I had a solid lifter 350 Chevy (3.48" stroke) with stock rotating assembly that I shifted at 7000 and it would rev to 8k.

 

[final5-0]

How about a non-roller 302 with a solid cam, a good set of heads and a carb? Back in the 70's I had a solid lifter 350 Chevy (3.48" stroke) with stock rotating assembly that I shifted at 7000 and it would rev to 8k.

No Brainer

Solid flat tappit lifters are nice and light

Grady

 

[Blackened302]

hehehe, i should ask the guy at the local advance--he's always talking about how he builds 454's that rev to 10k rpm's, hehe.

 

[Joes95GT]

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?

I wouldn't say "easier" but it would cost less. You also wouldn't go as fast. It all really depends on what you want to do. With increased piston speed, you need stuff that moves more air in order to maintain driveability. Strap E7's on a 7000 RPM 347 and you're going to work in an operating range of about 4000-7000 RPM. Put a set of AFR 225s on a 347 and you can probably work down into the 2500 range all the way up to 7000.

Honestly, I can't name a specific spring. I'd leave that to whoever I bought the cam from. I know you would need something with some SERIOUS open pressure.

Adam - Titanium retainers wouldn't be necessary. But, I'm sure you know, the small weight difference over the nose of the spring makes a TON of difference when it's opening and closing at 7000 RPM. It would definitely help out, but I wouldn't say it's necessary.

Joe

 

[turbogt]

Yep, Valvetrain is key.. Rod bolts aren't a bad Idea, but it really doesn't take that many mods to spin her to 7k. I accidentally spin my Vorteched, Stock longblock Cobra to 7k without a problem.

 

[nazstang]

i'd have to say , it's like building any other motor, you build it to your needs. in this case, you'd have to make the valvetrain one of the main focus. my friend built(quite a few years ago) a 306 longrod, forged goodies, all balanced to a 28oz fly and damp, twisted wedge heads(ported), victor intake(also ported) with a 90mm T.B., FTI cam, csi pump, and multiple Msd goodies. Sorry i can't remember the valvetrain to spec, but i did remember he had 2 prior setups, and the valve float was limiting him to 7K. Once he got this new springset in, it worked. spins to 8K with room to spare. pulls hard, got a bit over 400to the wheels and runs 10 flat on a T5bang: rebuilds it every 2 weeks). total motor cost was just shy of 9500, but he's racked on 30K of HARD miles, and no faliures yet.

 

[Dave2000GT]

Solid roller cam

 

[revhead347]

These posts are so way off key I don't know where to start. I leave for 2 weeks and this is what happens. To the OP, in order to rev to 7k rpms with any sort of longevity you need a purpose built 4 bolt main engine with a purpose built valvetrain. It will cost in the $10k range to build that engine. I think that is the best way to answer your question without wasting time on details. There is no reason to spin a stock block to 7k rpms. You can get all the power you need with the right cam combo and shift at around 6k rpms. There is no reason to compare an old pushrod engines to more modern overhead cam engines. It's apples and oranges. Modern engines have almost no reciprocating mass in the valvetrain. They also have deep skirt blocks and at least 4 bolts in each main cap if not 6 or 8.

Kurt

Kurt

 

[Noobz347]

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?

Kidding aside for a sec... Why do you want to rev to 7K? What are you trying to accomplish by revving to this specific number?

With a few choice parts and some sticky tires, those motors can make enough power to relieve you of the rest of your drive train.

So why 7K?

 

[90lxwhite]

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

I concur. The guy doesn't seem to want to spend or have the scratch for a $2k valvetrain job. Anything can be done for the right amount of money. We sent a man to the moon for Pete's sake....

 

[90lxwhite]

Kidding aside for a sec... Why do you want to rev to 7K? What are you trying to accomplish by revving to

So why 7K?

Ha! Yeah that was going to be my original response when I saw he thread title. Why? Make your horsepower at a lower rpm like the rest of the masses. If you're afraid of running out of rpm's go to a higher gear.

 

[90lxwhite]

4 cylinder cars can rev from here to kingdom come and make a whopping 200 hp. More rpm's don't necessarily make a faster car.