Small Block & Big Block Chevy Specific Mouse & Rat Motor Discussion & Conversions

High RPM small blocks?

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Old 06-18-2006, 02:41 PM
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Default High RPM small blocks?

Was looking threw google trying to find somthing, anything, about making a small block into a high revving engine. not redlineing to about 6k or near by, but going probably 7500. i know a bunch of you are all going, why the hell dose he want to rev it so high. well in honesty, i've always wanted a small block to rev up real high, love the way they sound when theyre screaming. and i was also wanting to later on turbo it....high pitch screaming small block....i need a tissue paper now. but i was wondering what all to make that happen. i have a bare block 350 in the back yard just sitting there waitin for somthign to happen. i was thinking of trying to find a small CI crank shaft to destrock it, since the shorter the strock the faster it spins and higher right? but i dont know about the valve train. have no idea on that area. but anyways that's what i was trying to get more info on. thanks in advance guys!
Old 06-18-2006, 03:23 PM
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Originally Posted by reject
Was looking threw google trying to find somthing, anything, about making a small block into a high revving engine. not redlineing to about 6k or near by, but going probably 7500. i know a bunch of you are all going, why the hell dose he want to rev it so high. well in honesty, i've always wanted a small block to rev up real high, love the way they sound when theyre screaming. and i was also wanting to later on turbo it....high pitch screaming small block....i need a tissue paper now. but i was wondering what all to make that happen. i have a bare block 350 in the back yard just sitting there waitin for somthign to happen. i was thinking of trying to find a small CI crank shaft to destrock it, since the shorter the strock the faster it spins and higher right? but i dont know about the valve train. have no idea on that area. but anyways that's what i was trying to get more info on. thanks in advance guys!
You'll need a quality rotating assembly and bearings for starters. Valvetrain wise you'll need a solid roller camshaft, shaft mounted rocker arms, titanium retainers, and some pretty tough springs and pushrods. A double roller timing chain might be a good idea too, along with modifying your oil system to handle 70psi or so.
Old 06-18-2006, 03:28 PM
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what type of rotating assembly from where? thanks for your help, hit me up on aim if you can to talk more thanks!
Old 06-18-2006, 05:16 PM
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in my circle track car, i had forged callies crank, eagle h-beam rods, forged srp pistons, h-series clevite bearings, solid cam, double roller timing chain...80 psi oil pressure at higher rpms, and a hise rise single plane intake with a 800 cfm c&s areosol holly double pumper..msd ignition..and i ran this motor to 7600 rpms ..no problems till I hit wall head on at 95mph at the that rpm..with that motor..
Old 06-18-2006, 07:08 PM
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Originally Posted by dirt_track_racer_81
in my circle track car, i had forged callies crank, eagle h-beam rods, forged srp pistons, h-series clevite bearings, solid cam, double roller timing chain...80 psi oil pressure at higher rpms, and a hise rise single plane intake with a 800 cfm c&s areosol holly double pumper..msd ignition..and i ran this motor to 7600 rpms ..no problems till I hit wall head on at 95mph at the that rpm..with that motor..
damn that must suck loosing that motor! mind if i ask how much that motor costed you?
Old 06-18-2006, 07:29 PM
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Check out www.speedomotive.com. I have one of their all-forged 383 kits and I spin it to 7000rpm sometimes. They balanced it for me and everything fit like it was supposed to. 4340 crank, Eagle H-beam 6" rods, forged JE blower pistons, ARP hardware, FluiDampr, etc. All for around $1695 plus shipping.

Just remember that rpm is WAY tougher on a motor than nitrous or a supercharger. The loads quadruple as the rpm doubles, which means the loads at 7200rpm compared to those at 6000rpm are 144% higher.

Jim
Old 06-18-2006, 07:51 PM
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how more often are you needing to do a rebuild of the motor?
Old 06-18-2006, 08:53 PM
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The NASCAR motors run like that all the time they are 358ci but they get there differnt ways I think usually a bigger bore with a shorter stroke but I don't know for sure but they do what you want and do it WELL. Look for info there.
Old 06-18-2006, 09:10 PM
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i'll check them out over there then, thanks for all of yall's help! got me in the right direction
Old 06-18-2006, 10:08 PM
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385 Cu. In
"010" 4 bolt main block
Forged SRP 16cc Dished pistons
Crower 4340 I Beam rods
Eagle 3.75" cast crank
Clevite H series bearings
Iron Eagle Platinum Heads
CNC'd by M2 Racing
242cc intake runner
321 CFM @ .700
66cc chamber
PSI Springs 235 lbs closed, 620 lbs open
Jesel comp series shaft rockers 1.6:1
Crower Custom Billet Steel Cam 254/257 @ .050 .712/.712 lift
Edelbrock Super Victor intake
Port matched to the heads
Fel-Pro 1209 gasket (2.38" x 1.38")
Holley 950 HP Carb
Wilson Manifolds 1.5" Carb spacer
Custom stepped headers 1 7/8" to 2"

This dyno sheet was before the intake was port matched and with 1 5/8" headers. 9.5:1 Compression. 43* total timing.
http://s5.photobucket.com/albums/y19...=DynoGraph.jpg
Old 06-20-2006, 03:11 AM
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I spin my SBC to 7,600 and then some sometimes.Crower Crank Oliver Rods and J E Pistons.
Old 06-20-2006, 06:45 AM
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Originally Posted by reject
Was looking threw google trying to find somthing, anything, about making a small block into a high revving engine. not redlineing to about 6k or near by, but going probably 7500. i know a bunch of you are all going, why the hell dose he want to rev it so high. well in honesty, i've always wanted a small block to rev up real high, love the way they sound when theyre screaming. and i was also wanting to later on turbo it....high pitch screaming small block....i need a tissue paper now. but i was wondering what all to make that happen. i have a bare block 350 in the back yard just sitting there waitin for somthign to happen. i was thinking of trying to find a small CI crank shaft to destrock it, since the shorter the strock the faster it spins and higher right? but i dont know about the valve train. have no idea on that area. but anyways that's what i was trying to get more info on. thanks in advance guys!
I'll be honest my knowledge of earleir SBC's is limited. However wanting such a motor to spin to those speeds regulary and relaibly with no increased maintance has to be a tall order.

Also if you are wanting that screaming sound I guess you may be referring to the noise a Ferrari makes. Sadly it is impossible to replicate with a SBC.

Generally to spin a motor (any motor) at high rpms you need several things.

One a built and very well balanced bottom end. Evidenty at such high speeds it needs to be in tip top order. Also you'll find very few long stroke motors that like revs. Most use a large bore combined with a short stroke as this means each piston only has to travel a shorter distance and far less inertia is involved.

Moving on to the valve train, OHV and push rods are not ideal for high rpm use. This is due to the rotational mass and indirect operation of the valves. You will need a heavy duty valve train setup to reliably handle high rpms but this will result in other down falls.

Following on from that if you plan to spin the motor that high you will evidently want to make use of the rpms so you will need some extra good heads and an appropriate cam selection to make power in higher rpms. But this is where you face another issue. Due to lack of curtain area 2v engines (OHV or OHC) have a limited rpm range in where they will make power, e.g.

x = operational range

1000-1500-2000-2500-3000-3500-4000-4500-5000-5500-6000-6500-7000-7500
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX - stock(ish) setup

------------------------------XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX - cammed and setup for high rpm use.

You will only ever have the same range of rpm to use but due to setup you can select what that range is but not increase it.

To provide enough breathing capability at high rpms you will need much larger valves than stock, but this means heavier spings and increased wear/friction on the the valve train. Also low rpm driveability will suffer greatly.

Increased curtain area allows better control at lower rpms and better breathing at high rpms, this is acheived by running multivalves such as a 4 valve setup. There is a company that makes some rather clever 4 valve heads for Chevy SBC's, check out there Advanced Tech forum there was a whole debate on it and multivalves (I can't remeber the name of the company right know). So this would sort out the breathing abilty although running 4 valves per cylinder on a push rod engine will certainly add more stress to the valve train but I beleive this system is fairly well proven.

Also if you plan on a turbo you don't particulary need high revs. As this would require a turbo with sufficent abilty to provide boost at such rpms which means it is likely to be more laggy in the lower rpms.

Lastly if it is the Ferrari screaming V8 sound your after, the reason you won't get it is because a Ferrari V8 is a DOHC short stroke motor. But the most significant factor is it uses a single plain crank. This means it has an even firing order, one bank then the next and so on. A traditional V8 has an uneven firing order where you will end up with two cylinders from the same bank firing one after the other. This is what gives the well known V8 rumble we are all used too and it is precisley why a Ferrari V8 doesn't make the same sound. Very few V8's are like this, Ferrari, TVR and Lotus are the only production ones I know of.

The Ferrari V8 is essentially two Striaght 4 engines with a common crank shaft, where as a SBC is essentailly two V4 engines.

Good luck with your project and I hope you get it sorted
Old 06-20-2006, 07:18 AM
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The car is a 1979 Camaro all glass except Q's / and roof one piece nose mar guard windows real nice 10 footer paint and detail on the car it has a 355 SBC 1970 4 bolt OEM steel crank coated C/A bearings Z 28 style pump anti cavitation molodon pan 7 qt w/windage cloyes alloy timing cover w/roller cam adjuster 2 cams come with the car both rollers chain and gears are a cam correct w/ L/S trencher crowler L/W rollers manley pushrods.080 black carbon finish Jessel rocker shaft 1.5 int 1.55 ext cam correct starret dial gauge valve adjustment tooling comes with it ( $400.00 alone )5.7 eagle ESP H beam rods with 2000 bolts brc L/W pistons .090 wall pins 1600 bob weight C/A total seal type rings AFR down nozzle injected style 227 spread ported heads 208 int 160 ext 1.550 pac alloy comp springs TiT 10* retainers fluid damper balancer edel small holley manifold not matched ( footbrake style ) an HP series holley 750 race carb w/ 11 inch filter and matching KN top Mallory pump and by pass regulator lge fram filter all # 8 stainless 5 gallon cell w/ foam and deck lid fuel door MSD 3 AL crank trigger MSD profile dist w/ ford cap and MSD wires Alloy dash w/ 9 thou's tach w/ recall and( 2 inch amber shift light ) 2 5/8 inch gauges, w/temp, trans/temp OIL w/2 inch warning bulb ( red ) volt meter and 70 amp alt w / jones cog belt drive, duel batteries 3 HP jegs starter TCI flex plate, alloy w / pump with plastic fan and moroso belt drive griffen alloy rad filled w/audi alloy coolent elect duel fan set up in front alloy trans cooler shoenfield stepped 1 3/4 to 1 7/8 X 3-1/2 collector 30 inch runners 9 inch collector sippers and egt bungs (lambus) both sides and they are rapped w/tan color rap 3-1/2 bullets mufflers super stock ATI style Glide trans and 8 inch conv .4 tenth brake big bucks unit ultra bell all rollerized latest mods available are done -- 9 inch ford 35 spline moser spool 14 - 32 15 tires front moroso springs konis manual after market box, stock sub w/brakes REAR QA1 shocks ladder bar suspension 2818 lbs car with a 270 lb driver front is 1590 rear is 1498 -- 3088 total w/ driver this car was completely freshed this winter everything was replaced or overhauled, everything, a must see runs in the cool 10:30 in the heat 10:50 foot breaking shifting at 8000 / 7800 traps one tenth trans braking , car was certed in 05 for 750 NHRA belts are june 05 PLEASE NOTE THIS IS A TURN KEY GO THIS WEEK TO THE TRACK CAR has 112 in it and is ready to go will sepp motor if you want to buy if willing to help take it out you can run and hear it i also have film of car let me know for my direct e mail PM me we shift this at 8000 and have shifted at 8500 but it does noting but spin up more goes no faster complete car and motor is 50 passes old no smoke no noizes no bull u want it i got it and its for sale jz
Old 06-20-2006, 09:48 AM
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Go to Schubeck Racing for your valve train, they have extremely light weight valve train components. Those components will get you to those high revs you are looking for.
Old 06-20-2006, 10:26 AM
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wow thanks for everyone's help so far! specially the parts list it takes to build such a motor! didnt expect such fast feedback! i'm going to see what parts i can start buying (small budget, but i'll get money in it when it becomes availible) and stocking them up until i can start getting everything machined together. again thanks alot for everyone's help!
Old 06-20-2006, 11:59 AM
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Originally Posted by 300bhp/ton
I'll be honest my knowledge of earleir SBC's is limited. However wanting such a motor to spin to those speeds regulary and relaibly with no increased maintance has to be a tall order.

Also if you are wanting that screaming sound I guess you may be referring to the noise a Ferrari makes. Sadly it is impossible to replicate with a SBC.

Generally to spin a motor (any motor) at high rpms you need several things.

One a built and very well balanced bottom end. Evidenty at such high speeds it needs to be in tip top order. Also you'll find very few long stroke motors that like revs. Most use a large bore combined with a short stroke as this means each piston only has to travel a shorter distance and far less inertia is involved.

Moving on to the valve train, OHV and push rods are not ideal for high rpm use. This is due to the rotational mass and indirect operation of the valves. You will need a heavy duty valve train setup to reliably handle high rpms but this will result in other down falls.

Following on from that if you plan to spin the motor that high you will evidently want to make use of the rpms so you will need some extra good heads and an appropriate cam selection to make power in higher rpms. But this is where you face another issue. Due to lack of curtain area 2v engines (OHV or OHC) have a limited rpm range in where they will make power, e.g.

x = operational range

1000-1500-2000-2500-3000-3500-4000-4500-5000-5500-6000-6500-7000-7500
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX - stock(ish) setup

------------------------------XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX - cammed and setup for high rpm use.

You will only ever have the same range of rpm to use but due to setup you can select what that range is but not increase it.

To provide enough breathing capability at high rpms you will need much larger valves than stock, but this means heavier spings and increased wear/friction on the the valve train. Also low rpm driveability will suffer greatly.

Increased curtain area allows better control at lower rpms and better breathing at high rpms, this is acheived by running multivalves such as a 4 valve setup. There is a company that makes some rather clever 4 valve heads for Chevy SBC's, check out there Advanced Tech forum there was a whole debate on it and multivalves (I can't remeber the name of the company right know). So this would sort out the breathing abilty although running 4 valves per cylinder on a push rod engine will certainly add more stress to the valve train but I beleive this system is fairly well proven.

Also if you plan on a turbo you don't particulary need high revs. As this would require a turbo with sufficent abilty to provide boost at such rpms which means it is likely to be more laggy in the lower rpms.

Lastly if it is the Ferrari screaming V8 sound your after, the reason you won't get it is because a Ferrari V8 is a DOHC short stroke motor. But the most significant factor is it uses a single plain crank. This means it has an even firing order, one bank then the next and so on. A traditional V8 has an uneven firing order where you will end up with two cylinders from the same bank firing one after the other. This is what gives the well known V8 rumble we are all used too and it is precisley why a Ferrari V8 doesn't make the same sound. Very few V8's are like this, Ferrari, TVR and Lotus are the only production ones I know of.

The Ferrari V8 is essentially two Striaght 4 engines with a common crank shaft, where as a SBC is essentailly two V4 engines.

Good luck with your project and I hope you get it sorted
A SBC that makes good power up to 7000 RPMs is not that uncommon. With the proper valvetrain parts and rotating assembly it could even live a long life. Obviously to make power up there you'll trade away some low end torque, but gearing is the answer to that problem. Even OHC engines with more curtain area sacrifice low RPM power to perform better in the upper RPM range, so I don't think that is necessarily something he needs to be concerned with since he is set turning some serious RPMs.
Old 06-20-2006, 10:20 PM
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We turn the motor in our Dirt modified around 7400-7600 on a weekly basis we have good parts in the motor but not crazy expensive stuff. We probably have around 8-10k in the motor itself. 2 years ago on the crew I worked on we were running $30,000 358 C.I. sbc and we ran a 9000 chip in the msd box and when we qualified the car it we would take gear out of the car and it would hit the rev limiter sometimes. Talk about lightweight we had one motor with honda rods and a super light crank, Dart HVH aluminum heads,money was not a object this thing was sick, the motor would shut off instantly when you let off the throttle because the bottom end was so light. It made around 640 H.P. and that is with parts that we had to run to make the motor DIRT legal. We would turn that motor 8,000 + RPM' s for a 100 laps on 3/8 -5/8 mile clay ovals.
Old 06-26-2006, 05:42 PM
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ARAO engineering is the name of the company that makes the 32 valve heads. Be forewarned they are really expensive and require some custom parts to get them to work. Here's a link to a guy on here that put some 32 valve heads on his LT1.
https://ls1tech.com/forums/lt1-lt4-modifications/423546-32valve-lt1-progress.html
Old 06-30-2006, 02:14 AM
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Originally Posted by firefighter
The NASCAR motors run like that all the time they are 358ci but they get there differnt ways I think usually a bigger bore with a shorter stroke but I don't know for sure but they do what you want and do it WELL. Look for info there.
I have a 3.340 crank out of a Cup car block that I got on eBay for $400. It's a billet Bryant unit that's good for 10,000 RPM. Don't forget an ATI balancer and some kind of belt drive for the cam. Premium valves and valvetrain parts are the most important. I usually budget $2000 to convert to a solid roller cam motor. that covers all the exotic parts and machine work.
Old 07-03-2006, 05:22 PM
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A destroked motor is definately the way to go if you want a screamer. Although mine is a big block, it still does what you want to do. I have a 399 inch big block that i shaft at 9200rpm. The way to make power with a small inch motor is to get the most compression you can and rev the hell out of it. We are currently building a 323 sbc for a 90 camaro to raced in NMCA Mean Street. Its starting as a 350 block .060 over with a 3.125 callies crank. IF your doing this the right way , you have to use aluminum rods and a custom set of pistons made to maximize your combustion chamber. We need to make around 800hp n/a to be competitive, so we have alot of work to do. If you want to see a list of parts to see what you may need check out the chevelle page in my site below. Have fun with that!


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