I've decided to start piecing together a max effort stock cube build. Too far out to have a goal in mind at this point but here's my question.

In a perfect world where money is no object I'd buy a set of nice aftermarket castings port them and go to town but in the past I have had nice results in my opinion having stock ls1 castings ported. I had a set of 241s done by Lloyd Elliot and have the stock 853s sitting on the shelf and not much interest in buyers.

So between the gm castings 853, 241, and 243 (maybe there's others I don't know off hand) what makes any one of them a better starting point? Are there restrictions that will limit just how well these will flow in ported form against one another? I understand the 243s are the best among the three and are a popular starting point but if I'm going to port and mill them really is there anything holding me back by using what I have and not spending the money on another set of heads?

 

If your question is "should I port and run 853s?", Answer is: They will perform well, although 243s would be better. If I were you, I would just buy a set of PRC LS6 heads ready to bolt on a go. It's going to cost you about a grand + to have the 853s rebuilt and CNC ported. Heck a set of 5.3 heads will suit you well too!

 

Here is an excellent article to read on the development of the 243 (799) casting for the LS6. Very insightful.

http://www.c5registry.com/documents/ls6/page4.htm

Ron

 

That's part of the question. Really what I would like to know is if you are able to work these different castings to the same level of performance. If so I don't see why one would be a better head than the others. I do understand the cost side of things and I did have a grand in doing the 241s. In the end if it takes less money to go with the PRCs for equal or better performance that's what I'd do. Right now its more of a hypothetical question since I have these heads sitting infront of me and I see no sense in scrapping them or leaving them on the shelf.

Thanks for the input.

 

Defiantly a good read. If I'm understanding correctly it would take a serious rework to get the benefits of the ls6 design out of a ls1 casting.

 

Well no, they are different casting designs. The 241s will not match the performance of 243s in stock form nor with equal amount of work done. All things equal, 243s will always make more power.

 

If it were me i'd stick with the 241's, and spend the extra money elsewhere....like a nitrous kit maybe

 

Correct, like adding metal or epoxy to mimic the changes done for the 243. AFR started with the 243 design and improved it....if I recall correctly.

Ron

 

Use the 243's, it will give you more in the end.

 

If I'm reading this right and you already have 241 heads ported by Lloyd Elliot, then why not just run them? It's been proven that well ported 241 heads can perform on par with ported 243's.

 

Main reason being this is a long term project to keep me busy and I'll probably pull the engine trans and ecu that im running now out and stick them in my 88 gmc pickup. The 305/700r4 in that thing could die any day.

Truthfully that was the question but you were the only one so far to say stick with what I've got.

 

I honestly would stick with them. If Lloyd Elliot did the port work, then you know they are top notch. Everyone bags on the 241 heads, but as Advanced Induction has shown, great power and ET's can be had with ported 241's. I know Damian (his user name) posted a few threads in the Dyno section proving this. Plus, if you use them, you've got all that money you would have used to purchase heads to buy something else to enhance the build. Hell, you could buy one hell of a nice nitrous setup with that money if that's your thing.

 

I don't think anyone here is arguing the fact that 241 can perform well, but dollar for dollar, they will not give you the max power. I bought PRC LS6 243 Heads ready to go for what AI quoted to port my 241s. I ended up selling the 241s and buying the PRC heads. In a way, the ported 243s were cheaper and perform better. The OP is going for max effort on a stock head, he needs to start out with the best casting...799/243.

I have never heard of Lloyd Elliot...so I can't vouch for them, but Texas Speed and AI heads are widely used and have dyno #s to prove their superiority. Some builds have seen close to 500RWHP with these heads.

 

I agree with you that the 234/799 heads are going to be better than the 241's, but since he's already got the ported 241's, no sense in buying, or paying to port, 243/799 heads. Now if he sells the 241's and gets a decent amount for them, then that's fine, but if he's looking for a MAX EFFORT LS1, then he needs to look at getting some TFS 215's or MAST Black Label heads.

Lloyd Elliot is not very well know in the LS1 world, but he's basically the "go to guy" when it comes to anything LT1.

 

Lloyd Elliot has been around a long while...

I'd just run those.

 

853s are probably the most undesireable head out there. 241s flow good but when you port 243s (799) they flow great

 

Ok so same porter same valves/springs/cam same cc same motor same dyno same etc...

How much more power is a well-ported 243 vs a well-ported standard LS1 head? I hear "more" and I hear "similar" and I've even told some folks that they would be same or similar at full tilt ported. Can we get a number or % or similar?

(I know the real LS6 243s have specific valves so let's assume those were placed in the LS1 head upon porting or that both got upgraded valves)

 

Compare an AI 241 and an AI 243. Even the AI high compression 241s come up just shy of the 243 program. But depending on goals and budget, that might be more value than having to buy 243 cores then get porting done.

 

Hmm. I see what you mean. They have flow charts for some of the programs but not others. And they go bigger with the 243 than the 241 in full tilt mode. Their HP ranges are a bit open as well.

Seems to me ~5% difference when ported/valved/cc'd similarly. What do you see? In "max effort" 5% can be huge so I'm not discounting it; just want to get to a conclusion since this subject seems to come up often..surprisingly often for 10+ year old castings!

 

Here you go: Plenty of evidence to show that ported 241's, when ported by someone who knows what they are doing, are plenty good enough to make some serious steam with the right combo of part.

https://ls1tech.com/forums/dynamomet...o-results.html

https://ls1tech.com/forums/dynamomet...m-results.html

https://ls1tech.com/forums/dynamomet...ck-valves.html