i wanted to know if the installed height on the iron lt1 heads were the same as the alum lt1 heads i think its 1.850 correct or am i wrong if someone could please give me some better info please.


also are the iron lt1 heads a 58cc head or are they 54cc like the aluminums i have found different info with different numbers.


any help would be great.

 

aluminum and iron's install heights are different

 

I believe the irons are 62 cc.

They have press in studs so be careful on spring pressure and cam selection.

They also do not have much retainer to seal clearance and if using a 1.6 rocker, the PR holes ned to be machined larger.

If the heads are off the car, no big deal, just spedn $$$ at a machine shop to make them work. If they are on the car, you are just limited to what you can do.

STOCK springs, retainers etc should be 1.780" if you are installing different springs and retainers, you need to find out where that springs needs to be set up at to work with your set up and shim to get them there.

Lloyd

 

i will be running the 26918 beehives and Ti retainers the studs have been tapped and threaded for screw in studs and i enlarged the pushrod holes myself. what is the 918's installed height on a iron head lloyd or anyone is it the same as a alum head?is there a way to machine the valve seal bosses to gain more clearence for retainer to seal or do i have to run a +.100 valve to clear my .600 lift on these irons?

 

Why sink money into iron heads? You can find alum ones for less than that machine work cost

 

cause i already had them done up here sitting awaiting use thats why.

 

1.750" is a good set upo ht for that spring.

Ti retainers are really not worth it on the bee hives (7g vs 11g).

I would stay away from the longer valves unless you must use them for large solid rollers. You can throw of rocker geometry real fast with longer valves.

I would get a 795 retaienrs, 611 locks and machine the guide boss down with a tool like this . . . . . .

http://competitionproducts.com/prodinfo.asp?number=7020

I have no idea where the stock guide boss limits retainer to seal clearance since machining them down is just part of thge process I start with on the cast iron LT1 and Vortec heads.

Lloyd

 

so i can machine the seal guides at the machine shop then, since i am having them install the larger valves i can just tell them to cut the seal guides down, then i can use like the Viton blue seals correct?and how much can be cut will the machinist know how much, and once they have been brought down will a .600 lift cam work with iron heads machined seal guides and a 1.750 installed height ?i only said i would use the TI retainers lloyd cause i already have them.

and lloyd how for sure of the 62cc number you wrote about the iron heads or is it less?
thanks for the info

 

yep, he can machine it doen for a smaller seal and give you clearance for .600+ lift with no problem. The exact seal you need depends on his cutter. Could be .530 or .500.

If you already have the Ti retainers, it makes sense to use them. I was just making sure you were not gonna spend $300 for Ti when the $60 steel would do the same thing.

I am about 95% sure on the 62 cc chambres. They look just like the Vortec head chamber. I guess the easiest way to know would be to CC one and then you know for sure. If they have not been milled, they should be 62 cc or so. Cast iron retains heat alot more than aluminum so the aluminum heads have a smaller chamber but can get away with it also. Iron is more efficient and will make the same power with less compression due to this (with everything else equal but as we know, the alu and iron LT1 chambers are not shaped equal).

Lloyd

 

thanks lloyd for the info as it was very helpful. yup the less compression and the clamping load of the iron head will serve good for my forced induction low compression setup especially since i pulled some meat out of the CC so hopefully i brought the heads up to a 66cc.