I want to upgrade my stock heads on my 99 SS cause I plan on installing this bigger cam (MS3) and a better intake (Weiand) in the spring. I know that the 241 heads found on 01 and 02 LS1 cars are better than the ones that came stock on my 99, but is it worth it to buy a set and get them ported, or should I just go with the LS6 CNC ported heads from TSP for a grand? I guess I just want to know if the LS6's are worth the extra money. But is it also worth it to get them ported, about how much would it cost to get a good port/polish on 241's?

 

Once ported I believe the 853 and 241 head will be the same. The LS6 heads will perform better though.

 

Any porting will make an improvement. You might consider milling them also and raise your compression to 11.0:1. Why not, seeing you would already have the heads off. This would be alot cheaper than buying a new set of heads. Another thing to consider is ebay motors. There are always great deals on LS6 heads for well under $1000.00. This would be a great starting point.

 

Unless you use stock size valves the heads wont work with that cam with out flycutting the pistons. Unless you have a big income to gamble with i wouldnt chance flycutting. May work for first 3k miles but then cost you a shortblock.

The TSP PRC stage 1 heads would be a good choice.

 

Good eye One Bad Z.

 

the 241's start off as being better heads. After porting them, why would they be equal to 853's?

 

^^^^^^^^
You got it backwards. Any LS1 head properly ported will flow about the same as each other. Be it 853, 241, or 243. Hand porting if done correctly can sometimes yield better results over just a cnc. Now I am not saying out of the box so don't try to jump all over me for saying that they are all equal. But if you have seen port jobs on all it is damn hard to determine which is which if there are no identifying marks on the head. Unless of course it is perimeter pattern.


Oh yeah. this is getting moved to internal.

 

Nicely put Orange. Only those who want to help vendors sell some new castings buy the idea that porting stock heads is pointless.

 

All ls heads dont flow the same. Our same 5.3l port put into a 241 casting flows several cfm less through the 241 chamber. We typically sell the fully assembled stage 1.5 241 heads for $650 per set with stock springs!

 

I got a set of 241's from my 02 T/A I'll sell ya for $150 if you want to try them out.

 

If I sent my own 241 castings to you,what would it cost to just Port /polish them, no springs,or valves?

Also was wondering what the 241's you offer flow?

Thanks
Warren

 

i just had a set of ported ls1 heads flowed against a set of ported 5.3 heads and a set of ported ls6 heads..i will post the results once i get the flow sheets back from the machine shop tomorrow. He hasn't flowed the ls6 ones yet but he did flow the 5.3 and ls1 heads and guess what, the ls1's outflowed the 5.3's by a few cfm and even had a smaller runner (222cc compared to 225cc's). All of the heads were done by respectable and well known companies but the LS1 heads were handported by a very good porter while the other heads are cnc'd.

 

I have a set of stock ported 241s with 2.02 1.60 valves
I got them from "badbird" on here & he made 430rwhp with a TSP 233/239 112lsa cam and these heads.

I havent used them because they wont work with my big cam. I will get these heads flowed after the 1st of the year.

 

A couple things

According to How To Build High-Performance Chevy LS1/LS6 V-8s, the early and late LS1 head ports are the same. The reason later heads flow better is the different casting methods producing a better as cast port. As stated in the first reply, the end result would be essentially the same no matter which head you start with.

I've never heard of anyone losing a shortblock due to flycutting. If done properly, and care is taken to keep any debris out of the cylinder wall, its the only way to run a stock casting head milled for the proper compression. You will need to get your heads as close to 59cc as possible for the best results, and I would not recommend a larger valve (which reduces piston to valve clearance).