vortec heads on an lt1?

[twgoodspeed]

im contemplating a similar thing here but I have a cc306 cam and valve train but the vortech headshave oversized valves and since I gotta change springs I figured a little port wrk would be in order, would the heating be a issue or not?

[Madman337]

I could be wrong but I was told long ago that an iron head keeps more thermal energy in the cylinder and that equals power but generally aluminum heads have more research-work ect done to them so they make more power then the run of the mill iron head. I would stick with the stock alloy heads if it were me.

[94Blackbird]

I could be wrong but I was told long ago that an iron head keeps more thermal energy in the cylinder and that equals power but generally aluminum heads have more research-work ect done to them so they make more power then the run of the mill iron head. I would stick with the stock alloy heads if it were me.

In this case the LT1 iron heads were in development 6 months longer than the aluminum heads. The Vortecs are basically the LT1 iron head except with standard flow coolant provisions. They flow more than the aluminum heads stock to stock (I think 202 intake Al to 230 iron is the general concensus, but I haven't flowed either set of heads myself, so don't quote me), but the advantage isn't there to justify going to the iron heads unless that's what is already on the engine.
The iron heads don't dissipate heat as quickly as the aluminum heads do, which in theory means that for a given compression ratio the iron heads will make a little more power due to the retained combustion heat. The downside to this is that the iron heads are more prone to heat soak, which can lead to pre ignition problems if the heads get too hot.

[Viper]

The cast iron 96 Impalla SS cast iron heads were the best flowing stock heads for the LT1. Aluminum LT1 561,374,643's in order of best to least flowing.

Here is a list of various smallblock chevy heads flow tested Stock along with aftermarket heads. Includes LT1 374's LT4's and vortecs.


http://purplesagetradingpost.com/sum...orld Sportsman


Post #20 Lloyd Elliot
http://www.camaroz28.com/forums/lt1-...s-62301/page2/



Numbers vary with the cylinder head and the flow bench operator along with testing parameters.

http://carprogrammer.com/Z28/Cylinde..._head_flow.htm


Results of cylinder head porters and aftermarket manufacturers vary as well. Think the best Flow to use is the average.

http://www.fierolt1.com/lt1_lt4_headflow.htm


In this exerpt from the table I think the results are listed Wrong The 96SS Cast iron Impalla SS numbers are 230I/147E @.0500 Lift as the extra flow was developed and used as prototype for the cast Iron 96-97 Vortec heads casting numbers 062 and 906 3 sawtooth heads.

Avg stock Lt1

	60.2	119.1	170.9	198.9	206.4	200.9	46.1	93.6	123.5	141.2	153.2	156.0	1110.8	5615.0	424.3	71.9%	798.4
LT1 Cast Iron Stock (Impala 94/5)	55.0	119.0	179.0	214.0	230.0		48.0	91.0	128.0	140.0	147.0		1112.4	5576.5	472.9	70.4%	783.3
LT1 Cast Iron Stock (Impala 96)	58.0	117.0	174.0	207.0	221.0		57.0	107.0	135.0	146.0	150.0		1111.6	5525.8	454.4	70.8%	786.8

http://www.onedirt.com/tech-stories/...k-chevy-heads/