1974 Chevy Big Block Trouble
09-11-2007, 10:40 PM
#1
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1974 Chevy Big Block Trouble Alright, when I take my 77' Nova to the strip and manually shift my automatic trans. the motor will not turn over 5800rpm. It begins to sputter like a vehicle with a rev limiter would.
Any suggestions as to what the problem could be and some solutions would be much appreciated.
[Specs 1977 Chevy Nova]
-1974 454 (.060 over)
-flat top pistons
-rectangle port heads
-air gap intake
-lunatti cam .544 lift(.544 duration)
-MSD ignition
-750 double pumper
-headers with flowmasters (2 1/2")
-electric fan
-10" 2500 stall converter
-3.73 gear ratio
-400 trans.
-timeslip 12.6@ 108mph
Any suggestions as to what the problem could be and some solutions would be much appreciated.
[Specs 1977 Chevy Nova]
-1974 454 (.060 over)
-flat top pistons
-rectangle port heads
-air gap intake
-lunatti cam .544 lift(.544 duration)
-MSD ignition
-750 double pumper
-headers with flowmasters (2 1/2")
-electric fan
-10" 2500 stall converter
-3.73 gear ratio
-400 trans.
-timeslip 12.6@ 108mph
Last edited by JC454; 09-12-2007 at 09:45 PM.
09-11-2007, 11:06 PM
#2
I can think of a lot of things I don't feel like typing. The list is too long.
Whats the combustion chamber volume on your heads? (or casting number)
What kind of valve springs do you have?
What do you have for a fuel system?
What jets are in the carb?
What ignition coil are you using? (do not use the red blaster)
Last year I built a 468 for a '75 nova, it ran low 11's easy but is was a very well planned build. I had a 6000 rpm chip in the MSD. More compression, bigger cam, intake, carb, oval port merlin heads, 3" exhaust, but otherwise close to what you have.
Here are some pics of my build up.
It was kind of weak at first, I went from a 750 carb to 850 DP, 2 1/4 exhaust
to 3" , stock 5/16 to 8AN fuel line with a 172 GPH carter mechanical fuel pump. and it woke right up.
Whats the combustion chamber volume on your heads? (or casting number)
What kind of valve springs do you have?
What do you have for a fuel system?
What jets are in the carb?
What ignition coil are you using? (do not use the red blaster)
Last year I built a 468 for a '75 nova, it ran low 11's easy but is was a very well planned build. I had a 6000 rpm chip in the MSD. More compression, bigger cam, intake, carb, oval port merlin heads, 3" exhaust, but otherwise close to what you have.
Here are some pics of my build up.
It was kind of weak at first, I went from a 750 carb to 850 DP, 2 1/4 exhaust
to 3" , stock 5/16 to 8AN fuel line with a 172 GPH carter mechanical fuel pump. and it woke right up.
09-14-2007, 11:24 PM
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hey man been busy anyway,
heads-14096188 1970-71 454 Open 118cc service replacement ls-6 markIV
fuel- holley "blue" 110gph pump regulated @ 8lb.
carb..- 0-4779c holley original jets that came with the carb couldn't find out size
unless I take bowls off.
coil- I'm afraid I do have the blaster, is their something I should know about?
valve springs- I ordered the ones Lunati recomended to use with cam 00024
but valve floating could be the problem due to insufficient spring preassure.
heads-14096188 1970-71 454 Open 118cc service replacement ls-6 markIV
fuel- holley "blue" 110gph pump regulated @ 8lb.
carb..- 0-4779c holley original jets that came with the carb couldn't find out size
unless I take bowls off.
coil- I'm afraid I do have the blaster, is their something I should know about?
valve springs- I ordered the ones Lunati recomended to use with cam 00024
but valve floating could be the problem due to insufficient spring preassure.
09-15-2007, 07:45 AM
#4
Quick reply for now...
Someone who builds custom distributors, Dave Ray, forgot the name of his company. He told me the MSD blaster 2 coil is made in Mexico and very it's common for them to over heat and fail internally due to the cooling oil used inside them. If you get the MSD chrome blaster 2 it says made in USA on the bottom, it's actually made by someone else and has a different cooling material in it.
As far as flat tops and 118cc heads it has about 8:1 compression, you can increase power and still run on pump gas by getting it up around 10.5:1.
Someone who builds custom distributors, Dave Ray, forgot the name of his company. He told me the MSD blaster 2 coil is made in Mexico and very it's common for them to over heat and fail internally due to the cooling oil used inside them. If you get the MSD chrome blaster 2 it says made in USA on the bottom, it's actually made by someone else and has a different cooling material in it.
As far as flat tops and 118cc heads it has about 8:1 compression, you can increase power and still run on pump gas by getting it up around 10.5:1.
Originally Posted by JC454
hey man been busy anyway,
heads-14096188 1970-71 454 Open 118cc service replacement ls-6 markIV
fuel- holley "blue" 110gph pump regulated @ 8lb.
carb..- 0-4779c holley original jets that came with the carb couldn't find out size
unless I take bowls off.
coil- I'm afraid I do have the blaster, is their something I should know about?
valve springs- I ordered the ones Lunati recomended to use with cam 00024
but valve floating could be the problem due to insufficient spring preassure.
heads-14096188 1970-71 454 Open 118cc service replacement ls-6 markIV
fuel- holley "blue" 110gph pump regulated @ 8lb.
carb..- 0-4779c holley original jets that came with the carb couldn't find out size
unless I take bowls off.
coil- I'm afraid I do have the blaster, is their something I should know about?
valve springs- I ordered the ones Lunati recomended to use with cam 00024
but valve floating could be the problem due to insufficient spring preassure.
