I have read a couple posts over in LT1 tech about putting standard SBC 15º heads on an LT1. Flow would be vastly inproved with a set-up similiar to this IMO. Anyone know general details and machine cost that would be associated with matching up the coolant passages and making the 15º head reverse cooled? What about the intake manifold, i assume this would have to go too, unless someone makes some sort of adapter to convert from a 23º to a 15º.

Any opinions or thoughts are welcome.

 

you cant make a LT1 head become 15*, you could go to like a 20-21* degree angle MAYBE, but that is extensive work.

You would have to buy 15* heads and have them converted to be used with reverse cooling....

A guy i know from the MFBA converted his -10X brodix heads to reverse cooling....so i'm sure you can do it to 15* heads also

 

Is it practical to go this route, or would money be better spent on ported AFRs?

Common phil, im waiting for your response since you see to be the heads guy around here.

 

Do a search under my username. There was a pretty big post on this in this forum a little bit ago

 

IMO, putting that much $ into LT1's isn't a good investment. You can move valves, or angle mill the heads.. but when you figure approximately .100" for every degree you roll it over, you're talking about alot of work for 1-2deg... hell that may get into the spark plug hole.. I'd have to measure, but even then you've gotta put it back on the mill and remachine head bolt holes etc.

As far as converting SBC to lt1.. well yeah if you have a suitable intake then sure. Never the less.. most peoples goals are easily met by keeping things far less complicated, so I wouldn't recommend it offhand. If you want to make big power, just go SBC, IMO anyway.

I'm sure chuck can probably shed more light on this than I can. My partner and friends have done this in the past, but not while I was around, so I'm only going on comments they've made in the past. I know they even did something like this back at S.A.M. I'd have to mock it up on a block and see what kind of intake work we're looking at... but still.. more complicated than most people need to make things. KISS.. keep it simple, stupid

 

http://web.camaross.com/forums/showt...threadid=39413

Heres the old post that was mentioned before. I dug it up

Phil is saying pretty much what was said in that post also. It can be done, but not worth the money. Some have done it, but IMO, the cost out wiegh the benefits.

Thanks for the replies. Guess i'll be sticking with the my old future plans of the ported AFRs.

Jared

 

All depends on your goals. If you want to build a 500 rwhp LT motor then you can do that with a well built stroker. If you want something over and beyond that then you may want to look at some alternatives.
This is when going with a 15, 18 or canted-valve head really starts to look like a good idea.
I personally can make a set of LT1 heads go over 310 cfm. It's not by any stretch.. an easy thing to do though. Considering the time (and yes time is money) involved in such an effort, you could buy a raw set of 18º heads and port them (have them ported) to your needs.
If you're building an engine that's gonna need shaft-rockers, custom pistons, etc., then it may be just as feasible to go this route. Again, you have to have realistic goals.

Take care,
Chuck Riddeck
Progressive Race Engine Development

 

Chuck-
Thanks for the reply. My long term goals are to make 400rwhp NA on a killer heads/cam package, and have the internals capable of ~200 shot of N20. As of now, i think the best option for me would to build a blueprinted 355, but that is a long ways off.

As of now im shopping for a 12 bolt rear. Then I'm going to get into the heads and cam. I just like to have a rough plan drawn in my head of where i want my car to be in the next year.

Anyways, you mentioned getting LT1's to flow in the 310 cfm range. Is that a stock or aftermarket casting? If you are talking about a stock casting, please PM me with details and pricing. I was thinking about buying bare AFR 190s and having them ported, but i would have no problem dropping mega money into the stock heads if it is possible to have them flow what a set of ported aftermarkets would do, of course comparing your porting cost to the forementioned option.

Jared

 

Jared,

Not to speak FOR chuck.. but those were in fact LT1 castings. As you'd expect, they were highly modified.. and when someone comes to us and tells us they want 300+cfm outta LT1's, but want to be able to use std. valvetrain pieces, then I tell them it'll cost them $2800 or so. So.. when given the choice of having killer LT1's, or having new bare castings from AFR worked.. I'd generally always suggest the new casting that doesnt require lots of machinework and headwork trickery . Thats my opinion though... we'll probably do something like that to my car since I'm rebuilding it.. but it's more for fun and research than it is something to sell .

-Phil

 

Jared,

Here is the point I try to get across to everyone who asks me this type of question.... ie. how much would it cost to work a set of castings to 300+ cfm?
My answer... you probably don't need the port volume associated with a 300+ cfm head. Your goal is to go 400rwhp NA... a 300 cfm port in that case is simply overkill. Your money would be better spent in other areas. Any good engine builder will tell you the same thing.
My old LT1 was 408 cid, was running a custom intake, shaft rockers and a lot of other non-standard items. My goal was 500+ rwhp, therefore I needed to develop the cylinder head to that extent. Not anything out of the ordianary for what we do but then again... I only had personal time involved in the effort.

I'm currently putting a 15º LT1 together (just laying a plan right now) for Mindgame. His goal is to make 550-575 rwhp. I don't have a problem with motors of that level but I usually don't even discuss it in much detail unless I know someone is serious. The fact is that it's not cheap to do this. Everyone would like a normally aspirated 600+ hp small-block street car. The reality of the matter is that most can't spend the kinda $ it takes to put an engine of that level together and make it live a relatively long life.

For 400 rwhp, just stay with the stock castings. Match your components and you're there without taking out a second mortgage.

Best of luck to you.

Chuck Riddeck
Progressive Race Engine Development

 

I'm planning on converting some 15 or 18 degree SBC heads to put on my Z28 when i get to seriously modding it. Access to milling machines and all are ready available to me(cousin owns a machine shop). I also plan on getting Hogan to custom make me an intake to match (plenum-style setup for boost). Not sure yet on the design I want for the intake cause I plan on designing my own when I get deeper into engineering at school and send the plans to Hogan. Statics, Dynamics, Fluid Dynamics, and Fluid Mechanics really wake one's mind up as to how an engine works. Ever thought of the air we breathe as a fluid?

Someone mentioned that other modifications would be needed, is this true? Will I have to get off-set lifters, rockers, etc to make a SBC race head work on an LT1? I can't see any reason to use 23 degree heads for the hp I plan on making, the design is just too....restrictive (for lack of a better word). People always bash the LT1 in favor of the LS1 b/c of the difference in the heads. Well I'm gonna eliminate the weak link and build an LT1 like one should be built. Or I may just go for a BBC swap instead.

Any and all help is appreciated.