High RPM Street small block

Walline · Post by **Walline** » Mon May 17, 2004 5:52 pm

Has anyone had anyluck running high RPM(8000 range) on a street motor. I have been toying with the idea of my big heads on a 350. With the large cross section I would need to spin the snot out of it, but I really want to keep the compression around 11:1. I realize the motor would not make much low end grunt:) but I would gear for that. What makes me ask is I Is compression important if I am willing to sacrifice lowend? I know it sounds crazy but 8000 RPM small chevy's "sounds" GREAT! THANKS EVERTONE!
ps I use the term "street" loosely!

speedtalk · Post by **speedtalk** » Tue May 18, 2004 12:32 am

How much HP are you trying to make?

Walline · Post by **Walline** » Tue May 18, 2004 12:47 pm

Don thanks for the reply. As far as Hp around 500? How would lower compression effect the engine, besides lose of low end torque? What am I forgetting? I will probably run a 406 again and just lower the compression so I can get some more street time with it. I am just tossing around combos right now! THANKS!

speedtalk · Post by **speedtalk** » Tue May 18, 2004 1:47 pm

I agree with Chris, used Nascar SB2s are the deal - can't beat the price/performance ratio. They only problem is the RPM required to make them work. The upside? It would be impossible to NOT make way more than 500hp.

What heads are you thinking of using?

Now this is just my opinion, but for the street, the bigger the motor the better. That way you can take gear out of the car and still run good at the track. If you're stuck on using a SBC, how about a 420" or 434"?

As for compression, I'm with you, keep it low - you can't set a national record on the street. Lower compression will lower peak tq and hp, but not the rpm they happen at - the heads mainly dictate that.

By the way, I do have a set of Nascar SB2s if you're interested.

Walline · Post by **Walline** » Tue May 18, 2004 3:54 pm

I agree on the cubic inch thing. I was just thinking about doing something different! Don, I have always wanted to try a set of SB2 heads! They are reaching the ends of my cash flow for racing! What does a set of SB2 heads run? I researched them about a year ago. If I remeber, headers was a concern? The heads I currently have are box stock Pro topline 235cc AL I am trying to get a flow bench so I can work with them. I was told by pro they flow 312@.700 28 inches(I think that is lofty) They are not raised runners, but the runners are about .200 taller then a felpro 1204, if I remember correctly. They ran (what I thought)Great on my 14:1 406 in a drag car, but I thought about using them on a street motor! Thanks, Chris Walline

speedtalk · Post by **speedtalk** » Tue May 18, 2004 4:27 pm

Hey Chris,

You can get a fresh set of SB2.2 heads complete with rockers and a manifold for $2500-$3000.
http://donsgarage.com/images/sb2-2.jpg
http://donsgarage.com/images/sb2-4.jpg
http://donsgarage.com/images/sb2-3.jpg
Probably overkill for what you're doing.

Making your own headers is easier than you think - especially if you're not looking for every last HP.

I don't think you'll have any trouble making 500hp with the heads you've got though.

Torquemonster · Post by **Torquemonster** » Thu May 27, 2004 1:21 am

It is possible to have an 8000rpm small block that is very streetable.

see www.araoengineering.com

they make 32 valve conversions retaining stock cam location etc and have proven reliable to 9500rpm. They make several head variations in 4 valve and it is possible to go from mild to a 1000hp small block naturally aspirated.

The 32 valve engine has many advantages over the best of the conventional designs. It will be vastly superior to an 8000rpm 2 valve engine.

tk · Post by tk » Sat May 29, 2004 10:50 am

4 years ago (the motor is still in top shape daily driver)
I built a 355 ci sbc that made 500hp @ 460 tq on 91 octane 10:1 comp.

TFS heads Flowed 260 cfm threw the intake manifold at .500" (vic jr.)
Manley 6" rods, SRP flat top 2 reliefs, Comp cam Hyd roller cam .502" lift,
1.5 roller rockers, steel crank, 4 bolt block, ARP everywhere, Edelbrocke 750 carb.
Balanced, blueprinted.

Simple combo and very strong , had 400 tq at 2500 and stayed above 400 tq until 6500rpm.

Just thought I'd share a simple setup!

EngineTech1 · Post by **EngineTech1** » Sat Jun 19, 2004 2:06 am

I can't count how many people I've heard talk about building a high rpm street engine to turn over 8000 rpm. I am wondering if these people just have different priorities than myself. Maybe so. Heres my idea on engines period, street or otherwise. I want a powerful engine, not just peak power but a nice broad power band with high average hp. I start out by deciding how much power I want to make. Then I build an engine based on that. If I wanted a 500 hp street engine I would decide on what heads to use that had the smallest port and valve that would flow the airflow necessary to make my hp goal and then build the engine as big as I could reasonably go within cost or space restraints to keep the power band as broad as possible and make the power at no higher of an rpm than necessary. Then gear the car accordingly. I am always trying to build an engine that will result in a fast car. But if you just want an engine that turns super high rpm's then spend the money on the valvetrain and plan on freshening on a regular basis. I'd advise anyone to really think about what they want out of their combination before building their combo simply to achieve some rpm that sounds cool. But if all you really care about is high rpm then go for it.

tk · Post by tk » Sat Jun 19, 2004 9:03 am

dano73327 wrote:I can't count how many people I've heard talk about building a high rpm street engine to turn over 8000 rpm. I am wondering if these people just have different priorities than myself. Maybe so. Heres my idea on engines period, street or otherwise. I want a powerful engine, not just peak power but a nice broad power band with high average hp. I start out by deciding how much power I want to make. Then I build an engine based on that. If I wanted a 500 hp street engine I would decide on what heads to use that had the smallest port and valve that would flow the airflow necessary to make my hp goal and then build the engine as big as I could reasonably go within cost or space restraints to keep the power band as broad as possible and make the power at no higher of an rpm than necessary. Then gear the car accordingly. I am always trying to build an engine that will result in a fast car. But if you just want an engine that turns super high rpm's then spend the money on the valvetrain and plan on freshening on a regular basis. I'd advise anyone to really think about what they want out of their combination before building their combo simply to achieve some rpm that sounds cool. But if all you really care about is high rpm then go for it.

I agree 100% .

I think all this interest with high rpm motors comes from the younger crowd where stock Honda's and so on come stock with peak power at 8500rpm.
Not realizing why and what is needed .
Personally I rather have a motor that makes 500hp at 5500rpm then the same hp at 7500rpm.
I try to have a strong wide power band with the torque coming in as low as possible and hang in for the longest possible.

The setup I mentioned in the previous post is a pretty basic and easy deal to do.
I feel better when using strong parts , it lets me sleep better at night.

That setup can be done with less but might not last 10-15 yrs like that one will.

Guest · Post by **Guest** » Mon Aug 23, 2004 6:41 pm

[quote="tk"]
Simple combo and very strong , had 400 tq at 2500 and stayed above 400 tq until 6500rpm. What rpm did that motor make peak power at? Just curious

quote]

tk · Post by tk » Mon Aug 23, 2004 7:44 pm

Anonymous wrote:
tk wrote: Simple combo and very strong , had 400 tq at 2500 and stayed above 400 tq until 6500rpm. What rpm did that motor make peak power at? Just curious

quote]

6200 rpm if I remember correctly