>6500
306, 331 or 347
- Thread starter Insayne
- Start date
umm i think you mean <6500...but either way.
The killer is that the main caps start to chatter(pull the main off a broken block and the mating surface will have black spots on it from this) a turbo motor will make the same power at the same RPM longer because its not yanking on the crank like a blower belt does. Add in the fact that the 50 oz stock stuff is super heavy you can't get a lot of RPM out of it w/o the crank starting to look like a jump rope at RPM. Once a main cap moves out of line the block splits and you know the rest, girdles can't prevent this, so don't buy into them.
The killer is that the main caps start to chatter(pull the main off a broken block and the mating surface will have black spots on it from this) a turbo motor will make the same power at the same RPM longer because its not yanking on the crank like a blower belt does. Add in the fact that the 50 oz stock stuff is super heavy you can't get a lot of RPM out of it w/o the crank starting to look like a jump rope at RPM. Once a main cap moves out of line the block splits and you know the rest, girdles can't prevent this, so don't buy into them.
excuse my <,> dyslexia
modo
Well-Known Member
BigTang said:
caps dont chatter... detonation is what does the cracking 99.9% of the time. stock or factory stock rebuilt type motors have tighter tolerances along with bearing that are not meant for high rpm. if it is run at high rpm that is when a bearing will spin, lose oil pressure then boom.
factory blocks go in the lifter valley then it goes down. blower motors with factory dampeners typically go at the front main up to the cam bearing due to vibrations there from the dampener shifting and the crank letting go between cyl # 1 and # 2
also a turbo motor will make the same power mainly because it is producing its max cfm because it is not dependent on engine rpm as a blower
fwiw i use to spin my factory shortblock to 7000 rpm in 4th to make it the full 1/4. gear change would have killed my 60' so i left it. had a good dampener and it lasted the 4 seasons till i stopped running that motor.
That?s only half the story a well built short block would have the proper clearances and at the edge the caps will squirm and walk with out a good stud and proper machining. Even then its still prone to happen.modo said:
Sort of, they split there because the main webs are weak and starts to distort and the stress is transferred to the extremely thin valley which in turn gives and drops the cam into the oil pan. Note to self, buy the strongest intake available to hold motor together.modo said:
Its side loading that kills the front of the block. That?s why you see guys w/ big centrifugal chargers running a support from the blower to the shaft along w/ cog belts, it takes the load off w/o reducing the belts ability to get the job done.modo said:
No one questioned this, my statement was that a turbo motor would live longer assuming both were making beyond 500 rwhp and tuned by someone that knew what they were doing.modo said:
I shifted at 6800 w/ my home assembled stock short block w/ stock cam so I understand what is required to get things done w/ factory parts.modo said:
i'm not starting a pissing match, i'm just trying to keep a good tech discussion going because i'm excited to talk about something besides which dome light looks better.
This is why I built off of a 351w SVO block 
modo
Well-Known Member
BigTang said:
well you are being generous that everyone has a motor built by someone who can measure tolerances for a given application and knows the proper weight oil to run for that given rpm range
factory blocks are thin plain and simple. detonation blows them apart
anyone that runs a large blower (like me) has a crank support to keep the bracket from flexing. bracket flex equates to belt slip and on a cog setup belts that get thrown. people that run cogs are not concerned about side loading the crank. a cog setup will cause more damage to the crank on decel as you have all the momentum of the blower now beating the snot out of the keyway on the crankshaft. this is why people dual keyway their crank and now some of the newer blowers will free spin on decel to prevent crank problems
im not looking for a pissing match either but there is a lot of mis-information out there on what parts can and can't due when 90% of the time it is the wrong application or put together by a joe that shouldn't be putting oil in a car let alone picking up a dial indicator (not meaning you)
modo
Well-Known Member
white95 said:This is why I built off of a 351w SVO block
in the early 90s these blocks didn't exist. look at the early days of pro5.0 when normal people could compete. people were FLYING with what would be considered junk today and all on stock blocks
modo said:
truer words were never spoken.
My advice to anyone looking to build a motor is to check out SBFtech.com and READ everything 5 times. I swear the 1st time I read about the things these guys were doing i was completely shocked, it basically says everything you've ever been told or read was a lie (magazine motor builds, etc.)
modo said:white95 said:This is why I built off of a 351w SVO block
in the early 90s these blocks didn't exist. look at the early days of pro5.0 when normal people could compete. people were FLYING with what would be considered junk today and all on stock blocks
Yeah but that was 20 years ago my friend!
Sounds like a plan
Your tire budget better be tight lol
modo
Well-Known Member
white95 said:modo said:white95 said:This is why I built off of a 351w SVO block
in the early 90s these blocks didn't exist. look at the early days of pro5.0 when normal people could compete. people were FLYING with what would be considered junk today and all on stock blocks
Yeah but that was 20 years ago my friend!
that wasn't my point. in all honestly there isn't any benefit of going with a 9.5" deck as with all the added expenses of the swap you could build a killer 8.2" motor. now if you want a na motor with a lot of cubic inch then skip the 9.5" stuff and go right to a 385 series motor and make 500+ inches. but thats me
You're right on both of your previous statements, I was just poking the hive! I got a killer deal on the block and it kinda snowballed.
white95 said:
Isn't that what usually happens. We all start out as: I'm just going to re-ring my stock block and put a cobra intake on it. Next thing you know your buying (or budgeting to) a 9.5 with some 200+ runner heads. lol
