706's or 243's on a 5.3?
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706's or 243's on a 5.3?
Was wondering if I should do ported polished 706 heads or go with milled 243's (otherwise stock 243's) with a 212/218 cam. I've seen a couple of magazines lately doing some build ups on 5.3's and they used trick flow "205" heads which I think are based on 706 castings. I know milled, ported and polished 243's would probably be best, but not in the budget.
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I tossed this idea around alot myself and spoke with alot who did the swap and this is my opinion.... If you have no heads: go with milled 243's and see the small/decent gain. If you already have the 706's keep them because the cost of new gaskets, bolts, labor, and even the 243's would be alot to pay for the small 10-15 hp gain. Hope that helps.
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How much and what thickness for head gaskets if milling 243's for 5.3?
I was thinking .030-.035 for milling of the heads to have a slight bump in compression over stock 9.5 to 1. Looking for direction to go
I was thinking .030-.035 for milling of the heads to have a slight bump in compression over stock 9.5 to 1. Looking for direction to go
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#9
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by the time you buy a set of 243s have a valve job and mill done your about the same cost as a used set of PRC ported 5.3 heads
OR
find you a $50 set of 706s,get some 2.0 intake valves from a set of 317s for dirt cheap
Have them milled and a performance valve job done for about $500 total!!!
By doing this it will out flow the stock 243s and have more compression with no change in intake runner size
OR
find you a $50 set of 706s,get some 2.0 intake valves from a set of 317s for dirt cheap
Have them milled and a performance valve job done for about $500 total!!!
By doing this it will out flow the stock 243s and have more compression with no change in intake runner size
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So how much would I mill the 706's since there already stock 5.3 heads. I wouldn't mine upping the compression a little, I'm already running 93 with the tune. So it sounds like for heavier trucks the 706's might be better for low end torque and the 243's are more for upper end hp. What if any is there between the 862's and 706's????