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Discussion Starter #1
block is a 1969 010 350/355
.30 over summit brand pistons( Hypereutectic Pistons SUM-17350-30) stock but new 350 crank. cloyes timing chain SUM-G2600 summit gasket kit




comp cam 280h Duration 280/280, Lift .480/.480 lobe 110


vortec heads 12558062 (#062) specs unknown but they are stock. 1.5 scorpion rockers.


flowtech long tube headers


holly 750 carb eldebrock intake manifold #7516


trans is a th350 with a b&m hole shoot 3k stall 3.73 posi rear end


overall goal was to make it around 400hp. and my other question would I be able to safely spray a small amount of nos as in 30,50,or 75 and it work with the pistons and crank I have?
 

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First thing....if you haven't modified the Vortecs to accept that .480" lift then you have your first problem, as totally stock they are only good to ,470" lift maximum. and some won't even go that far.

Second problem,,,if those heads have stock springs on them then they are not good enough for that cam. Not enough seat or open pressure.

The pistons will handle up to a 150 hp nitrous shot if everything done with the nitrous is correct (timing retard, fuel pressure, plate jetting). Guys who are on top of their tune-up have shot more than that on hyper pistons, I have heard of 250 hp shots being done on hypers, but it takes experience to push then that hard, not recommended for a nitrous newbee.

Put together correctly with good timing tune and carb tune you will make your 400 hp
 

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block is a 1969 010 350/355
.30 over summit brand pistons( Hypereutectic Pistons SUM-17350-30) stock but new 350 crank. cloyes timing chain SUM-G2600 summit gasket kit




comp cam 280h Duration 280/280, Lift .480/.480 lobe 110


vortec heads 12558062 (#062) specs unknown but they are stock. 1.5 scorpion rockers.


flowtech long tube headers


holly 750 carb eldebrock intake manifold #7516


trans is a th350 with a b&m hole shoot 3k stall 3.73 posi rear end


overall goal was to make it around 400hp. and my other question would I be able to safely spray a small amount of nos as in 30,50,or 75 and it work with the pistons and crank I have?
Is this a have or a want list?

The L31 head, hyper pistons and nitrous is edgy, any detonation and the pistons are gone, you can build in some safety by using a detonation sensor tied to an advance retard box or go with forged pistons which still last longer with a detonation sensor.

The L31's have to be modified to accept lift pretty much above .45 inch and they will need different springs for that cam this gets you cost wise into the area where an aftermarket aluminum head should be considered.

400 horses would take porting the L31's and using 1.6 rockers at least on the intakes another reason to include aftermarket heads in this combo.

Bogie
 

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increase valve lift .050 on early sbc (cheap)

i have used this many times with no failures on 327 & early 350 engines. chuck up the valve stem in a lathe & carry the top groove out .050" discard the exaust spring retainers & use only intake retainers for all valves. buy springs with 110-120 closeing pressure. after installing, the tops of the valves will be almost flush with the retainer but will work with stock rocker arms. this 1.25" spring setup is light weight & good for 6500 rpms with flat tappets.
 

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Discussion Starter #5
First thing....if you haven't modified the Vortecs to accept that .480" lift then you have your first problem, as totally stock they are only good to ,470" lift maximum. and some won't even go that far.

Second problem,,,if those heads have stock springs on them then they are not good enough for that cam. Not enough seat or open pressure.

The pistons will handle up to a 150 hp nitrous shot if everything done with the nitrous is correct (timing retard, fuel pressure, plate jetting). Guys who are on top of their tune-up have shot more than that on hyper pistons, I have heard of 250 hp shots being done on hypers, but it takes experience to push then that hard, not recommended for a nitrous newbee.

Put together correctly with good timing tune and carb tune you will make your 400 hp


the heads have been done to except the cam, and springs and such have been done as well. I guess as stock I mean they have not been ported polished too a extreme level.
 

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Discussion Starter #6
Is this a have or a want list?

The L31 head, hyper pistons and nitrous is edgy, any detonation and the pistons are gone, you can build in some safety by using a detonation sensor tied to an advance retard box or go with forged pistons which still last longer with a detonation sensor.

The L31's have to be modified to accept lift pretty much above .45 inch and they will need different springs for that cam this gets you cost wise into the area where an aftermarket aluminum head should be considered.

400 horses would take porting the L31's and using 1.6 rockers at least on the intakes another reason to include aftermarket heads in this combo.

Bogie



a have list. oh my wish list is totally different haha, I have worded stock wrong, the heads have been touched as in so they'd work with the comp cam but any porting polishing shaving has not been done. sorry for the confusion lol. I have concerderd aluminum heads in the future
 

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Discussion Starter #7
i have used this many times with no failures on 327 & early 350 engines. chuck up the valve stem in a lathe & carry the top groove out .050" discard the exaust spring retainers & use only intake retainers for all valves. buy springs with 110-120 closeing pressure. after installing, the tops of the valves will be almost flush with the retainer but will work with stock rocker arms. this 1.25" spring setup is light weight & good for 6500 rpms with flat tappets.


good too know I appreciate it
 
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