862 heads worth touching?
10-09-2011, 12:23 AM
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862 heads worth touching? so i have a set of stock 862 castin heads off a 5.3 l sierra that have around 30k miles on them are they worth sending off to get port and polished and maybe milled for a stock internal ls1?
if i can/should mill them with maybe plans of an ms3/4 cam ( or simliar cam) in the future what would be a safe amount, thanks!
if i can/should mill them with maybe plans of an ms3/4 cam ( or simliar cam) in the future what would be a safe amount, thanks!
10-09-2011, 10:05 AM
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They are good heads for high compression builds. I think they already have a small chamber. They are not worth spending a lot of cash on. I would do just a basic rebuild. Seals , springs maybe a valve job or just hand lap the stock valves.
10-09-2011, 12:19 PM
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im just thinking if i can save $1k on heads would help me alot atm if i can just send these out to the machine shop and get them to get the heads to flow a little better to get more out of them but
10-09-2011, 07:55 PM
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Just wanted to point out in case you don't know 862 heads have a smaller intake valve(1.89) than all the 5.7 heads.If you buy ported 5.3 heads these are replaced with larger valves and the chambers are worked around them.I don't think I would bother with the 862 heads if you don't want to change the valves but it will increase your cost a bunch.
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12-06-2011, 11:26 AM
#8
Those heads do pretty well once ported and with a larger valve. The stock valve is pretty small so its almost a requirement that you get some larger ones in there. We have been porting these heads for quite some time with good success. My last car had a set of our PRC 5.3l heads and an MS3, I was able to make 475rwhp and 412 rwtq. See my sig for the rest of the mods. You can send your heads to us if you would like us to CNC port them for you.
12-06-2011, 03:51 PM
#9
Those heads do pretty well once ported and with a larger valve. The stock valve is pretty small so its almost a requirement that you get some larger ones in there. We have been porting these heads for quite some time with good success. My last car had a set of our PRC 5.3l heads and an MS3, I was able to make 475rwhp and 412 rwtq. See my sig for the rest of the mods. You can send your heads to us if you would like us to CNC port them for you.
