lt1/vortec combo
06-25-2007, 12:03 AM
#3
Not only that, back in my third gen days I remember reading that the vortec heads are based off the LT1 heads and then cast in iron. Could be wrong but sounded plausible at the time.
06-25-2007, 06:14 PM
#5
The Vortec heads are based on the iron LT1 heads.
For less than the machining costs to the Vortec heads you could pickup a set of LT1 irons and have zero headaches.
I have three sets in my garage and I know I am not the only one, should be easy to find if you try.
For less than the machining costs to the Vortec heads you could pickup a set of LT1 irons and have zero headaches.
I have three sets in my garage and I know I am not the only one, should be easy to find if you try.
06-25-2007, 06:36 PM
#6
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Caprice, I know you don't like me, but entertain my question for the masses 
How bad is the heat soak on the irons, in comparison to the alus? Which do you run? Would swapping out stock alu's for stock irons (or irons with some massaging) be stupid? This is a question based on having little to no money, where having Alu's worked on is too expensive.
How bad is the heat soak on the irons, in comparison to the alus? Which do you run? Would swapping out stock alu's for stock irons (or irons with some massaging) be stupid? This is a question based on having little to no money, where having Alu's worked on is too expensive.
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06-25-2007, 07:14 PM
#8
Originally Posted by Formula350
Caprice, I know you don't like me, but entertain my question for the masses
How bad is the heat soak on the irons, in comparison to the alus? Which do you run? Would swapping out stock alu's for stock irons (or irons with some massaging) be stupid? This is a question based on having little to no money, where having Alu's worked on is too expensive.
How bad is the heat soak on the irons, in comparison to the alus? Which do you run? Would swapping out stock alu's for stock irons (or irons with some massaging) be stupid? This is a question based on having little to no money, where having Alu's worked on is too expensive.
Would be a technological step backwards, save and port your stockers when you can afford to
06-25-2007, 08:35 PM
#10
I am running aluminums. If the car was still my only transportation as it was for years I would have just mildly worked a set of irons. I have heard of several cases of heavily worked irons cracking after a couple years of use so if aiming high I might stay away from them unless you plan to accomplish airflow through boost instead of heavy porting. For boost I THINK they would be a little more durable and the 64cc chamber may make it easier to achieve target compression without a big dish.
Since I was able to make the car secondary transportation I decided to take advantage of the far greater R&D that has been put into getting the most out of the aluminums. In the end I still drive it more than I planned too and compromised drivability less than I thought I would but now if I break it I still have a car to drive with the wagon.
In stock form though the irons work better than most want to give them credit for, a friend with a 160K mile cop car, full weight, large driver, 3300 stall, 3.73s, 87 octane mailorder Creech tune, good CAI/Exhaust with cats, AI spec'd cam(similar to HOT) was running 13.5 at the Impala Nationals in St. Louis the other weekend. Might not sound like much till you understand that the stroker cars with the popular heads and cams were running 13.1-2 and I was running 12.8-9. Was 105F and the track temp was 130-140 so traction was not to be had and power was way down for everyone but the nitrous cars.
Since I was able to make the car secondary transportation I decided to take advantage of the far greater R&D that has been put into getting the most out of the aluminums. In the end I still drive it more than I planned too and compromised drivability less than I thought I would but now if I break it I still have a car to drive with the wagon.
In stock form though the irons work better than most want to give them credit for, a friend with a 160K mile cop car, full weight, large driver, 3300 stall, 3.73s, 87 octane mailorder Creech tune, good CAI/Exhaust with cats, AI spec'd cam(similar to HOT) was running 13.5 at the Impala Nationals in St. Louis the other weekend. Might not sound like much till you understand that the stroker cars with the popular heads and cams were running 13.1-2 and I was running 12.8-9. Was 105F and the track temp was 130-140 so traction was not to be had and power was way down for everyone but the nitrous cars.
06-26-2007, 08:22 PM
#12
They are spec'd at 64cc so it would take a fair amount of milling. The stock b-body head gasket is .029 compared to the f-body .049. Then again with iron you should run lower compression due to the better insulating properties.
People talk about the better cooling of aluminum but any heat not used to push the piston is wasted that means everything that leaves the radiator and any heat above ambient in the exhaust is waste.
People talk about the better cooling of aluminum but any heat not used to push the piston is wasted that means everything that leaves the radiator and any heat above ambient in the exhaust is waste.
06-27-2007, 12:10 AM
#15
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Originally Posted by 96capricemgr
The stock b-body head gasket is .029 compared to the f-body .049.
06-28-2007, 08:09 AM
#17
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Originally Posted by B4Cya
Or using the iron heads with the thicker gaskets to drop compression for a boosted application?
06-28-2007, 11:21 AM
#18
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Originally Posted by vtec
....but they are still iron heads and hold in more heat than alum. basically, a 9.1 iron head motor works like a 10.1 alum. head motor. (if both heads flow the same)
I wonder how much of the compression on the Iron head vs the Alu head is attributed TO the heads, or if the pistons are different too...
Anyone know how many CR points are gained from switching to the Iron head gasket? I don't expect much, but even .2 would be quite a bit IMO.
06-28-2007, 06:37 PM
#19
Pistons are the same, the whole shortblock is the same.
People talk like iron keeping heat in the chamber is bad but as I said above any heat the escapes the chamber is wasted. What an engine does is uses heat to expand gasses to drive the piston down in the hole, and heat that does something other than that is waste.
People talk like iron keeping heat in the chamber is bad but as I said above any heat the escapes the chamber is wasted. What an engine does is uses heat to expand gasses to drive the piston down in the hole, and heat that does something other than that is waste.
06-28-2007, 07:14 PM
#20
Originally Posted by Formula350
The Iron's flow more though. And swapping them over to a boosted app (if you plan to keep everything stock) I'd think would yield more boost potential.
I wonder how much of the compression on the Iron head vs the Alu head is attributed TO the heads, or if the pistons are different too...
Anyone know how many CR points are gained from switching to the Iron head gasket? I don't expect much, but even .2 would be quite a bit IMO.
I wonder how much of the compression on the Iron head vs the Alu head is attributed TO the heads, or if the pistons are different too...
Anyone know how many CR points are gained from switching to the Iron head gasket? I don't expect much, but even .2 would be quite a bit IMO.