Would 873 Cast iron heads work with a 5.3 block/crank and 5.7 LS1 rods and pistons?
05-07-2011, 07:33 PM
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Would 873 Cast iron heads work with a 5.3 block/crank and 5.7 LS1 rods and pistons? Hi Guys
I am putting a budget short block together from near freebe parts. I have a 04' 5.3 cast block that got wet and had the pistons rust into the cylinders. I grabbed a set of Corvette LS1 5.7 pistons and rods off of ebay for $80 and can get a set of cast iron 873 heads for probably free. What would this combo end up with for compression? I am thinking with a bit of a cam an intake and carb along with headers should end up with 400 hp without too much trouble. I could do a little head port and bowl clean up on my own to help that out a bit too. Any ideas?
Greg
I am putting a budget short block together from near freebe parts. I have a 04' 5.3 cast block that got wet and had the pistons rust into the cylinders. I grabbed a set of Corvette LS1 5.7 pistons and rods off of ebay for $80 and can get a set of cast iron 873 heads for probably free. What would this combo end up with for compression? I am thinking with a bit of a cam an intake and carb along with headers should end up with 400 hp without too much trouble. I could do a little head port and bowl clean up on my own to help that out a bit too. Any ideas?
Greg
05-07-2011, 10:20 PM
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with the cast iron heads, you wont be able to run as high a compression ratio as you would aluminum heads. the cast iron heads are basically the same as the aluminum head, and honestly as cheap as a set of 241's can be had, i would leave the cast iron heads set.
i built a Thunder Stock engine using the cast iron heads (rules) and it ran very well. 370 cubes, good solid roller cam and a GMPP intake and 850 carb...made close to 600 at the crank. but it took a lot of port work on the heads to get them where i needed them. i actually fucked one of them up by taking too much off in the wrong spot and had to weld and re work the port, but in the end, they flew just at 300CFM on the intake.
the cast heads can be good, just not worth the time and effort IMO.
i built a Thunder Stock engine using the cast iron heads (rules) and it ran very well. 370 cubes, good solid roller cam and a GMPP intake and 850 carb...made close to 600 at the crank. but it took a lot of port work on the heads to get them where i needed them. i actually fucked one of them up by taking too much off in the wrong spot and had to weld and re work the port, but in the end, they flew just at 300CFM on the intake.
the cast heads can be good, just not worth the time and effort IMO.
05-08-2011, 02:27 PM
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Well after going through some of the sticky info it seems these cast heads should be 71/72ccs and with the flat top LS1 pistons should net me about 9.5 to 9.7 to 1 compression. The way I see it, with a cam in the 230 range it should produce an easy 425HP with a good intake carb and headers. If I end up with the heads for free I should be able to put this motor together for pretty dam cheap. I like the challenge of trying to work with some discarded parts.
Greg
Greg
