Installing larger valves in 4.8/5.3 heads??
11-14-2001, 02:11 PM
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Installing larger valves in 4.8/5.3 heads?? First off what is the difference between the 4.8 and 5.3 heads? If any?
Between the 5.7 and 5.3 and 4.8? Specifically valve size and chamber volume?
Second I am pretty sure the 4.8 and 5.3 heads have
smaller valves than the 5.7.
What is required to install stock 5.7 size valves in the 4.8 and 5.3 heads? How much $$ to do that?
Will new seats be needed or simply a regrind?
Between the 5.7 and 5.3 and 4.8? Specifically valve size and chamber volume?
Second I am pretty sure the 4.8 and 5.3 heads have
smaller valves than the 5.7.
What is required to install stock 5.7 size valves in the 4.8 and 5.3 heads? How much $$ to do that?
Will new seats be needed or simply a regrind?
10-26-2004, 02:19 AM
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4.8l and 5.3l are the same heads.
The 4.8/5.3 come with 1.89/1.55 valves. The stock LS1 valves (2.00/1.55) are a direct swap. I would recommend a good quality valve job though. I would try to find a shop with LS1 experience as these heads, like all heads, are very sensitive to the type of angles cut. This can range anywhere from $75-$250 depending on the shop and type of valvejob performed. If you can swing the extra $$ of shipping, send the heads to one of the sponsors on right and have them perform this for you.
Jason
The 4.8/5.3 come with 1.89/1.55 valves. The stock LS1 valves (2.00/1.55) are a direct swap. I would recommend a good quality valve job though. I would try to find a shop with LS1 experience as these heads, like all heads, are very sensitive to the type of angles cut. This can range anywhere from $75-$250 depending on the shop and type of valvejob performed. If you can swing the extra $$ of shipping, send the heads to one of the sponsors on right and have them perform this for you.
Jason
