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This is a discussion on Proper compression? within the General Help forums, part of the LSx Technical Help Section category; I have ported heads and cam and it is obvious I should have done the lower end while I was ...
11-20-2006, 11:55 AM #1Ratdaddy07Guest
I have ported heads and cam and it is obvious I should have done the lower end while I was at it (122K on the car and it now blows through oil) so that is what I am planning now. I want to go with the 408 but need to know what comp. ratio is best I would like to put a 200 shot of nitrous to it and I want a motor that will last, so 8.5 10.6 or more? Anyone?
11-20-2006, 12:50 PM #2
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200 shot dual stage ( I assume unless you like looking at the sky alot) I'd be looking for 8.5:1 max 9:1....Cam lift not to exceed .500ish...dont fuck around with head gaskets....nor head bolts....only the best...
11-21-2006, 07:04 AM #3Ratdaddy07Guest
I plan on using the cam I have .580 so I better stick to the 8.5 and yeah dual stage would be the way to go, thanks for the advice. So one more question I see the Lunati rotating parts are much higher than most others are they worth it?
11-22-2006, 05:51 PM #4
Yeah I would run 9:1 with the New Total Seal ring pack....... They wind them in house and go off your exact finale hone #.... They are hard as a rock and a real pain in the A_S to file but we have multiple race motors out thre that have went this whole season and just got tore down for freshing and rings still look new.Follow there rules on running a "big" gap... Due to so much cyl. pressure you don't want the pigtails to hit eachother....
I would also run a cam with a 113 or 114...... Lift I would look at your flow #'s before I could spit out a # on that part. But for the street i would stay under .590".
On a what we consider a smaller unit of 200hp I would just run a progressive controller on the one unit instead of 2 stage set-up....Edelbrocks is Very user friendly.
Also make the valvetrain VERY sturdy......If you ever have a back fire you don't want the pushrod or rocker to break easy...... When that happens all that cyl. pressure builds until it opens the cyl. wall or the head.... Stay with a .120" wall pushrod...Don't be afraid of the bottle!!! Be afraid of your tune!!!
11-24-2006, 06:25 AM #5Ratdaddy07Guest
Great info thanks I have the pushrods down but still have the stock rockers I think I will need to update those, any suggestions. I have some cat roller rockers but they are 1.8's and I think that may be to much lift with the cam I have .580.
11-24-2006, 09:15 AM #6
Wouldn't you also want a lower LSA, say around 112 or so to help with cylinder pressure with the spray?
11-27-2006, 06:13 AM #7Ratdaddy07Guest
Don't know those are things I need to find out but if that is the case I would more likely just go with a 150 shot so I can keep the same cam it is brand spankin new.
11-27-2006, 04:13 PM #8
The nitrous Loves 114 at least Every time we tried the exact cam on a 114-112.
And Brian if your only going to spray 150 then I would run more comp. and more of a "motor" cam.
pm me your # I'l call you be a lot easier on the phone!!!