High RPM SBC ?
Thread Starter
Racer
Joined: Oct 2009
Posts: 441
Likes: 2
From: San Antonio TX
High RPM SBC ?
I want to build a SBC that will turn some R's .
Before I do What is a Great CI Combo ?
I have a friend who spins his BBC to 7200 in a Chevelle and my Boat turns 6500 on a 3/8" rod bolt basicly stock lower end BBC (ARP & other good parts used ) factory crank etc..
I would like to see a usable rpm up to about 7k or better ? ..my car is 4sp w/3.36 gear
I have a 400 shortblock and a (327 sm.journal shortblock that is already built, but the crank is cut .120 /.90 ) so I 'm shying away from this one
Before I do What is a Great CI Combo ?
I have a friend who spins his BBC to 7200 in a Chevelle and my Boat turns 6500 on a 3/8" rod bolt basicly stock lower end BBC (ARP & other good parts used ) factory crank etc..
I would like to see a usable rpm up to about 7k or better ? ..my car is 4sp w/3.36 gear
I have a 400 shortblock and a (327 sm.journal shortblock that is already built, but the crank is cut .120 /.90 ) so I 'm shying away from this one
Last edited by Rmorgan&11; Dec 9, 2009 at 09:36 AM.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I want to build a SBC that will turn some R's .
Before I do What is a Great CI Combo ?
I have a friend who spins his BBC to 7200 in a Chevelle and my Boat turns 6500 on a 3/8" rod bolt basicly stock lower end BBC (ARP & other good parts used ) factory crank etc..
I would like to see a usable rpm up to about 7k or better ? ..my car is 4sp w/3.36 gear
I have a 400 shortblock and a (327 sm.journal shortblock that is already built, but the crank is cut .120 /.90 ) so I 'm shying away from this one
Before I do What is a Great CI Combo ?
I have a friend who spins his BBC to 7200 in a Chevelle and my Boat turns 6500 on a 3/8" rod bolt basicly stock lower end BBC (ARP & other good parts used ) factory crank etc..
I would like to see a usable rpm up to about 7k or better ? ..my car is 4sp w/3.36 gear
I have a 400 shortblock and a (327 sm.journal shortblock that is already built, but the crank is cut .120 /.90 ) so I 'm shying away from this one
So put a 3.875 stroker in that 400 block and build it to do 7800 rpm. No problem 421 ci and it should be in the mid 600 hp.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
I've built a 7500 RPM 350 that's still going after 3 years (crossed fingers)
Gkull's right on, as usual. Top-notch forged rotating ***'y, solid roller cam and mondo heads, everyting balanced to a tee and held together with ARP studs
Gkull's right on, as usual. Top-notch forged rotating ***'y, solid roller cam and mondo heads, everyting balanced to a tee and held together with ARP studs
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
My 427ci will still be making power at 7500RPM you need to spend some money though. I like Callies cranks and if I did it again I would get a set of lighter I beam rods and the pistons I have are OK as they are pretty light. ( Sure there's even better stuff out there but this will do )
Key here is valve train and I would recommend shaft rocker setup. Once you have one you will never go back to stud rocker setup they are so stable.
And for 400 based motors you need big heads nothing under 220's and big solid roller cams
Key here is valve train and I would recommend shaft rocker setup. Once you have one you will never go back to stud rocker setup they are so stable.
And for 400 based motors you need big heads nothing under 220's and big solid roller cams
Thread Starter
Racer
Joined: Oct 2009
Posts: 441
Likes: 2
From: San Antonio TX
after I went roller top end on my BBC , never go back to flat tappets again ..
I have some other blocks and parts for my BBC I can sell to bring in alot of the funds, I don't have much time to race the boat anymore so I may sell it too ?
I have some other blocks and parts for my BBC I can sell to bring in alot of the funds, I don't have much time to race the boat anymore so I may sell it too ?
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Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I lost a 355 ci motor just trying to maintain 6500 rpm for 90 some miles in testing for a Nevada open road race. It is really hard on motors to stretch it's legs as you put it for any length of time.
I also broke the crank shaft on my first 427 small block. It was a 4340 cheap forged crank that couldn't handle running it to 7500 in the first 4 gears.
big ci is the way to go to get Vette to go from "Zero - 175 mph" in a hurry
I have bought a few of the over $3000 dollar rotating kits for small block from these guys.
www.flatlanderracing.com
Last edited by gkull; Dec 9, 2009 at 01:08 PM.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Higher RPM just kills motor longevity. So I build my motors to feasably withstand 8000 rpm and then cam them down and put a rev limiter to 7000 and then they last........... most of the time.
I lost a 355 ci motor just trying to maintain 6500 rpm for 90 some miles in testing for a Nevada open road race. It is really hard on motors to stretch it's legs as you put it for any length of time.
I also broke the crank shaft on my first 427 small block. It was a 4340 cheap forged crank that couldn't handle running it to 7500 in the first 4 gears.
big ci is the way to go to get Vette to go from "Zero - 175 mph" in a hurry
I have bought a few of the over $3000 dollar rotating kits for small block from these guys.
I lost a 355 ci motor just trying to maintain 6500 rpm for 90 some miles in testing for a Nevada open road race. It is really hard on motors to stretch it's legs as you put it for any length of time.
I also broke the crank shaft on my first 427 small block. It was a 4340 cheap forged crank that couldn't handle running it to 7500 in the first 4 gears.
big ci is the way to go to get Vette to go from "Zero - 175 mph" in a hurry
I have bought a few of the over $3000 dollar rotating kits for small block from these guys.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
FE bottom ends are really tough. The "Y" block with cross bolted mains and the LeManns capscrew rods were pretty much bullet proof. I've had several big block Mustangs and never once lost a bottom end. My problem was alway broken valves. No doubtedly from the valves floating.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I wouldn't bother with a stock OEM 400 block either if you are thinking 7500RPM that is mandatory aftermarket block with billet steel main caps ARP hardware everywhere
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I work on historic race cars. Even a real gt-40 and it is going to Le'Mans this spring. Back in the day for qualifying they used qualifying power engines and or changed the rpm limits compared to the endurance motor for the 24 hour race. We use modern rev limiters to keep the owners from blowing vastly superior modern built motors. On this GT-40 we also over geared it so it can not even get near red line in top gear. Where in qualifying motors you hear them bouncing on the rev limiter on the main straights
Just like a drag racing motor can last for a years worth of 1/4 mile bursts, but that same motor couldn't do a 500 miles trip on the interstate.
Just like a drag racing motor can last for a years worth of 1/4 mile bursts, but that same motor couldn't do a 500 miles trip on the interstate.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
I work on historic race cars. Even a real gt-40 and it is going to Le'Mans this spring. Back in the day for qualifying they used qualifying power engines and or changed the rpm limits compared to the endurance motor for the 24 hour race. We use modern rev limiters to keep the owners from blowing vastly superior modern built motors. On this GT-40 we also over geared it so it can not even get near red line in top gear. Where in qualifying motors you hear them bouncing on the rev limiter on the main straights
Just like a drag racing motor can last for a years worth of 1/4 mile bursts, but that same motor couldn't do a 500 miles trip on the interstate.
Just like a drag racing motor can last for a years worth of 1/4 mile bursts, but that same motor couldn't do a 500 miles trip on the interstate.
limit at 5.0 liter limit.
The 289 did not have a strong cross bolted block like the 7 liter ( 67
Mark 4 winner )
One thing good about the 289 it only had 2.25 size mains, slow bearing speeds, very short deck, light short rods, light pistons. Its lot easier to turn short strokes, very light parts around a circle for long periods of time,
much easier on parts, blocks.
but having said all this the old 426 and 427 nascar engines were turning
7600 rpm down the straits for several hours at a time.
Last edited by Little Mouse; Dec 9, 2009 at 02:06 PM.
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
I want to build a SBC that will turn some R's .
Before I do What is a Great CI Combo ?
I have a friend who spins his BBC to 7200 in a Chevelle and my Boat turns 6500 on a 3/8" rod bolt basicly stock lower end BBC (ARP & other good parts used ) factory crank etc..
I would like to see a usable rpm up to about 7k or better ? ..my car is 4sp w/3.36 gear
I have a 400 shortblock and a (327 sm.journal shortblock that is already built, but the crank is cut .120 /.90 ) so I 'm shying away from this one
Before I do What is a Great CI Combo ?
I have a friend who spins his BBC to 7200 in a Chevelle and my Boat turns 6500 on a 3/8" rod bolt basicly stock lower end BBC (ARP & other good parts used ) factory crank etc..
I would like to see a usable rpm up to about 7k or better ? ..my car is 4sp w/3.36 gear
I have a 400 shortblock and a (327 sm.journal shortblock that is already built, but the crank is cut .120 /.90 ) so I 'm shying away from this one
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Big ci and lower rpm is my preferred choice on motors. So did Ford when they decided to race 427's against the tiny 3000 cc european cars
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
We should not banter in someones post. But it takes a well built motor to stretch it's legs for a long period of time. I would not use the term several hours when in fact the old LeMans cuircut had only @8 mile straight. Most fast cars would only be doing max revs for sub three minutes at a time. Compared to open 92 mile road races that last for 20+ minutes.
Big ci and lower rpm is my preferred choice on motors. So did Ford when they decided to race 427's against the tiny 3000 cc european cars
Big ci and lower rpm is my preferred choice on motors. So did Ford when they decided to race 427's against the tiny 3000 cc european cars
I watched chasing classic cars last night the 289 datona coupe that won the SCCA championship ( ford only american manufacture to do it ) at auction went for seven million two hundred fifty thousand in this bad economy.
Last edited by Little Mouse; Dec 9, 2009 at 03:07 PM.
Safety Car
Joined: Sep 2009
Posts: 4,964
Likes: 28
From: Pittsburgh PA
stock 400 block here bored .040 cast crank, stock short rods, studded the 2 bolt mains and arp rod bolts, hyperutectic pistons, not even balanced. in a 3900 # car for 6 years. spin it to 7200 while blowing nitrous thru it. its an $800. swapmeet shortblock. years ago my $8000. + sm block with all the good stuff made 1 pass and kicked a rod out. go figure. used to run the stock 283 to 8000 rpm with a 4-speed and 5:38 gears. never had the pan off, bone stock shortblock from 1961