i am running out of puff at 4800rpm,, still running 13.1et though
need valve springs and will change with heads still on engine.




what is most common spring used to replace the stock springs without machine work.

 

https://www.alexsparts.com/valve-spr...rf-hyd-roller/

 

or the ls6 springs with comp retainers.

 

^^^ I have run both these and the Alex kit and prefer the GMPP LS6 spring/Comp 787 retainer combo.

I actually have a 400 going together myself. What cam do you run that is nosing over at 4,800 rpm?

 

its a crow cam and a custom grind,, the springs are holding me back,,its still as is got 378hp,,it will jump in comp ratio and rpm once we change springs

 

i will post my cam specs in a few hours as its 4.50am and time to go to work,,,
we had a crow cam made to suite my compression, cylinder head capability, rear end ratio and mostly compression ratio,,, never buy off the shelf cams if you are running anything other than a standard basic combination.


i have little over 300 rear wheel HP on a dyno and we can move it up with valve springs,,,,,i also needed a big carter mechanical fuel pump as it was running out of fuel at 4900,,pressure dropped to zero at wide open throttle,,the CARTER bolt on pump cured it and a 1mm hole was drilled in a brass fitting that is on the return line to the tank to retain a return for hot days,,it stays at 7lbs at wide open throttle and we picked up 90hp on a fuel pump change. You need an o2 sensor dyno to find all these little problems,,i can run 12.8 and am confident ..
the spring change will take my cylinder pressure up a little and i should go from 8.5:1 to closer to 9.0 to 1.. some will disagree but it will work.


we also removed the stock heavy springs from the MSD pro billet distributor and replaced them with lighter springs and now it advances like a rocket and this is extremely important.
The MSD distributors made in America are the only ones to use but the are basicly setup from the factory and really need to be set up for YOUR ENGINE combo. IT WILL MAKE A BIG DIFFERENCE

 

thank you mate,,will do...

 

https://outlook.live.com/owa/?id=648.../mail/inbox/rp


Please see the email summit sent me,,, in regards to springs

 

.050 ABDC 236
.050 ATDC 244


inlet lobe lift .3408 exhaust 3409
inlet valve lift .5112 exhaust valve lift .5114


lobe seperation 112


this isnt an off the shelf cam and i have lots of numbers on the sheet provided.
its a crow cam made in Australia for "this car",,its no good for another combination.


236
244


284
292


its for a 408ci motor with 8.5 compression and vortec heads an auto with 2500 stall and 3.08 gears...(but i now run a 3.42 diff..)


all these factors are really relevant and i dont understand people buying cams pre ground..


we see cams advertised for 283.400 chevs,,,no mention of comp ratio or gears.
its not a good thing to one size fits all scenario...

this engine idles around 17 degrese
and at full throttle runs to 36 degrese.


this is not a hot rod engine or a race motor,,its basicly a stock 400 and stock vortec heads and i am beeting cars with hot engines that are not setup properly.


i ran an old ford with a blown 671 302 windsor and i flogged him by 1 second.


i can run 12.7 and will without spending 1 cent after i get the springs on.