Worth doing?
10-02-2011, 06:08 PM
#1
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Worth doing?
Looking at a set of ported 5.3 heads. They have PRC .660 lift dual springs, ferrea 2.02 intake and 1.57 exh valves, titanium. retainers, multi angle valve job.. milled .030/ now have a 58cc combustion chamber. Is it with doing this swap?How much power would these yield on my stock lq9? What would it bump my compression to? Thanks guys
10-02-2011, 07:10 PM
#4
That is a STEAL! well worth the upgrade imho, i do think someone else cam chime in on the fly cuts for the valves if those heads will pose a problem. Im not real aure on the compression but i think it'll be close to a 10:8-11:1 please dont quote me on that. Get with the helpful crew at Texas Speed, or Richard @ WCCH. They are all very helpful on things of that sort.
10-02-2011, 07:31 PM
#6
I don't think you'd have to flycut unless there's massive lift in your cam. The theory is that since the valve is held open longer on a long-duration cam that the valve will still be down when the piston is nearing the top of its stroke. I'm running a 228/236 cam and there's tons of room. Of course, my lift is just .585"
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10-02-2011, 08:02 PM
#8
The more the compression means less room for the valve to travel. If you have a 11:1 compression and a donkey dick cam with tons of duration and lift there is a big chance you will hit a piston before your valves start to close. With a 10:5 and lower compression thats not an extreme issue id think. On a 10:8+ compression id be more concerned about that issue than anything honestly.
Swift: i dont think your 228/236 would really matter in your setup considering your compression isnt in the higher range.
Like i said contact a Pro of your concerns and go from there. Worst case you'll have to get a smaller cam.
Swift: i dont think your 228/236 would really matter in your setup considering your compression isnt in the higher range.
Like i said contact a Pro of your concerns and go from there. Worst case you'll have to get a smaller cam.
10-02-2011, 09:03 PM
#10
With just a head swap id think not but if you are wanting to be certain your not leaving HP on the table it wouldnt hurt for a scan to see if you are getting any KR or some reason its not liking the current timing table.
Im not a head/cam/tuning guru so i cant give you a 100% answer on this, nor how much HP/TQ to expect from the head swap. Id guess 25-30 atleast
Im not a head/cam/tuning guru so i cant give you a 100% answer on this, nor how much HP/TQ to expect from the head swap. Id guess 25-30 atleast