Nervous about head swap - need help
11-23-2005, 07:40 AM
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Nervous about head swap - need help I have a 2003 Silverado with a 5.3 and a small (210/218, .551/.551, 112) cam plus bolt-ons. Recently I've been talking with a few sponsors about a set of "Stage I" heads to go with it, but I'm a little nervous about making the decision.
I've discussed two options. The first is porting of the bowls, 5-angle valve job, 1.94 intake and 1.57 exhaust valves. Due to the porting, the heads would have to be milled .024 to get the chamber volume back up to stock 62cc (9.5:1 CR). The second option same as # 1 but mill the heads .045 to lower the chamber volume to 57cc (10:1 CR). I assume that these are based on stock thickness head gaskets.
If I run a .045 head gasket I gain another .25 point of compression, and my squish area would be ~.037. Would this be the best route or should I stick with stock gaskets? Do you think I am going to have p to v clearance issues? What if I went to a bigger cam (216/224, .551/.551 115 or 113)? What length pushrods should I run? I have 7.4s now, would 7.35s be good?
Thanks
I've discussed two options. The first is porting of the bowls, 5-angle valve job, 1.94 intake and 1.57 exhaust valves. Due to the porting, the heads would have to be milled .024 to get the chamber volume back up to stock 62cc (9.5:1 CR). The second option same as # 1 but mill the heads .045 to lower the chamber volume to 57cc (10:1 CR). I assume that these are based on stock thickness head gaskets.
If I run a .045 head gasket I gain another .25 point of compression, and my squish area would be ~.037. Would this be the best route or should I stick with stock gaskets? Do you think I am going to have p to v clearance issues? What if I went to a bigger cam (216/224, .551/.551 115 or 113)? What length pushrods should I run? I have 7.4s now, would 7.35s be good?
Thanks
11-28-2005, 09:33 AM
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Chambers on ported 5.3L will be in the 62 cc range without milling.
The bowl are not ported but can be polished with (some blending around valves and plug hole).
The ports (intake and exhaust) are what is ported.
Send yours to a competent porter (like TEA) and get a stage 1.5 on them (2.02,1.57/1.585).
Or talk to GUNNAR at Patriot and see what deal he can give you with head exchange.
Also TSP can do it for you via PRC
.045 Cometics will be sweet, but you could run .040's and have an effective 59.x cc chamber.
I wouldn't change cam unless you want to go much bigger.
The bowl are not ported but can be polished with (some blending around valves and plug hole).
The ports (intake and exhaust) are what is ported.
Send yours to a competent porter (like TEA) and get a stage 1.5 on them (2.02,1.57/1.585).
Or talk to GUNNAR at Patriot and see what deal he can give you with head exchange.
Also TSP can do it for you via PRC
.045 Cometics will be sweet, but you could run .040's and have an effective 59.x cc chamber.
I wouldn't change cam unless you want to go much bigger.
11-28-2005, 02:46 PM
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Thanks for the reply, I've been speaking with WCCH, they seem to do a lot of truck heads and the head work that I listed is based on what they have recommended to me. They are going to do them for me on exchange.
I'll probably stick with the small cam until I do the head swap and see what kind of improvment I get from the heads alone. I'm also going to throw a 2600 stall converter in there. I'm looking for 350 rwhp / tq from the 5.3 N/A. I just figure I'll need more cam to get there.
What about pushrod length? Should I get 7.35s?
I'll probably stick with the small cam until I do the head swap and see what kind of improvment I get from the heads alone. I'm also going to throw a 2600 stall converter in there. I'm looking for 350 rwhp / tq from the 5.3 N/A. I just figure I'll need more cam to get there.
What about pushrod length? Should I get 7.35s?
