I've seen alot of discussions lately talking about converting the Brodix 18X heads for an LT1, one of the main requirements I've noticed that put's me out of the ball game is 18 degree pistons. I've just spent a good chunk on a forged bottem end so changing pistons isn't really an option.

What about some of the Brodix 23 degree stuff. I realize that you're talking about shaft type rockers, but are the gains not worth the buck so to speak because the 18 degree stuff can flow so much better. 23 degree Brodix heads would use a standard 23 degree piston though, correct? Even their CNC 23 degree stuff looks to me like they flow pretty good, are their other issues converting their 23 degree heads that I'm not seeing?

 

There are LTX heads capable of over 300cfm in order to make it worthwhile to convert anything else over you would want them to flow even more yet. Intake manifold selection is also a concern.

 

From the rumors I'm hearing, the 23* LTx Trick Flows are turning out to be pretty impressive. Not the factory ported versions... the fresh castings that can be worked over by a skilled porter.


Anyone with some inside knowledge want to confirm or deny those rumors?
Maybe even lend some insight?

 

Try this:

http://web.camaross.com/forums/showthread.php?t=305775

 

O.K. so what I'm hearing is that if you're going to stick with a 23 degree head you can get comparable results with a TFS or AFR casting, making a Brodix 23 degree swap an expensive alternative. I've already talked with Lloyd about a set of Trick Flows.

I read the above referenced thread and it looks like I should consider an LT4 intake as well. The SCR is slightly troubling, high 50's with my proposed 389 bottom end will be getting close, but I'm hoping with a properly matched cam and a good tune to be able to run safely on pump gas. What kind of cost, roughly, are you talking to get a set of TFS heads, to run close to 300cfm, excluding bare castings cost, but with the rest of the valvetrain stuff ready to bolt on.

 

High 50's?? What is this you speak of?

 

Combustion Chamber volume.

 

I'm confused, Bret was talking about the combustion chamber being too large to get the desired compression, and your worried about it being to high and being safe for pump gas. Opposite ends of the spectrum there....

Roughly without getting too specific:
Excluding the bare castings, but including a complete valvetrain with cam, rockers, lifters, and heads and intake matched and ready to bolt on, you need a budget in the range of 4k dollars.
This does not include money for gaskets, plugs, wires ect that you may want to replace at that time. You also need to take a serious look at your exhaust, fuel pump/injectors, throttle body, ect and make sure everything else is up to snuff to utilize these heads to their potential.

-brent

 

I read Bret's post wrong, I was thinking that he was saying about the largest they could get the chamber, after angle milling was in the high 50's range. About the minimum I can afford to go with the combustion chamber is about the stock 58cc, anything smaller than that and it starts to be close, SCR wise, of course that doesn't really tell you much, but even DCR wise using a pretty good size duration cam and I'm beginning to push the magic 9:1 area. I realize that most of this can be corrected with a custom cam, and I plan on doing that, but for planning purposes, I have to use the specs for something. Ideally I'd like to be at about 60cc, that gives me a nice cushion, but I plan on having the cam and heads done together, so it should work out fine. At any rate the TFS heads look like they might work fine as a starting point, I especially like their availability compared to AFR's, and what people are saying about the quality of the casting.

As far as the price I was just curious as to what kind of cost porting them at the level that Bret was talking about would be. I've got the supporting parts, this is part of a complete new long block that I'm building. I think I can do the heads and cam, I already have rockers and lifters, for a little less than 4, maybe not 300cfm, but 280-290 anyways. That is if I go that way, I'm still considering a single-plane intake option, modified for FI, in which case I might be looking at different heads altogether. Just have to see where I'm at budget wise, but I expect that I've got another close to 10k to go, not counting what I've already spent on the short block. That isn't all engine mind you, new clutch, tranny parts, and a few suspension mods. I've made up my mind that I'm going to get exactly what I want, a fast streetable car. I think it can be done, but from what I've learned so far it's all about the combination as a whole.