If you have found a set of 561's that out flow the earlier heads post up your results. I have flowed several sets of each casting and have always found that the 561's were about 10 cfm off. Trust me when I say that if I could find any untouched set of LT1 heads that will out flow what's on my current motors, I would be interested in buying them!

 

Like I said, I may have simply mis-understood. My cyl head guy has ported many sets of LTx heads, he has flowed all of the castings. But not several sets of each. He's not as well known as LE, AI, TEA, etc, but I feel his results are on par with all of the above. We had a conversation about this subject several years ago, I may have simply misunderstood what he told me, but I thought he said that he had found that the 561's flowed a few cfm better in stock form. Maybe not. I'll call him tomorrow and ask him to dig up his findings again.

 

Who do you use Colin, Eric B?

 

I had always read that they were better, so I fixed a set for my Stocker. I was very dissapointed when it slowed down (about 1/10th, which is huge for a Stocker). To be honest I thought that something else was wrong with the car. When I started flowing all of my heads I found that all my 561's were off. I now flow every set of heads that I get. I am serious when I say that I am interested if you can find a good set of 561's.

 

Chris Bernd of Cylinder Head Specialties (CHS) in Wellington, KS

Well I trust your info, I'm sure that you've flowed way more sets of as-cast LT1 heads than he has. If I knew of a set of 561s that flowed better than average, I'd certainly tell you where to find them Like I said, this conversation was several years ago, and the set of 561s that he flowed are now ported and on my car...

 

I was curious about the different castings, so I did a search and read most of the threads I could find both here and at CZ28.com. I could have sworn I saw a post by Lloyd Elliot that was several years old indicating that the stock 561's flowed a little more than the other castings in stock form. I could have easily misunderstood the numbers he reported, but that was my impression based on his comments.

 

I have also personally heard in the past that the 561's flowed more but never have done any personal flow testing or seen evidence to know for sure. I won't argue with someone who has tested both though, maybe the 561 thing is a myth?

 

Maybe Lloyd can post up what he has seen. I will bet that he sees a lot more of this stuff than any of us! There is always the chance that different batches of the same casting are better. I purchased several sets of 561's when I read that they were better (on this forum). My experience was bad and cost me a bunch of money. Maybe someone else has had a good experience that they can share? I do feel that the 1997 intake is better with unported heads.

 

Would you mind explaining why? What about with ported stock heads? Jw because I would be interesting in learning, thanks.

 

Here is the thread I found at CZ28.com. I believe this poster is Lloyd Elliot.

http://cz28.com/forums/showthread.ph...&highlight=561

 

I run Stock Eliminator which requires unported castings. The ports on the 1997 intake match the ports on the heads where the earlier intakes don't. If I were running ported heads and intake I would use the 1993 intake because it doesn't have the crossover to block flow. The 1994+ fuel rails work best for all applications, but require a little welding for use on the 1993 intake. My experience with this stuff comes from years of trying to get the most out of stock castings. I have piles of this stuff! A lot of the old stuff is driving around Shelby, NC in street cars.

 

You will also see that I tried to buy those heads in that thread! (GUMP)

 

Cool thanks! I sent my stock '97 Intake to Lloyd for porting and received a different intake back, it must be a '94-'96 or so, first five numbers are 10108. Anyways I was just curious, appreciate the responce!

 

Thanks guys, appreciate all the feedback. I talked to LE Thursday and I'm gonna go with these 561's worked by him.

-SS

 

Sorry for reviving this ancient thread, but you wouldn't happen to still have this spare pair of heads and be willing to sell? I'm trying to find a cheap set to try my hand at porting myself, thanks!

 

I dont think he posts here anymore.

 

That tends to happen over a decade. Anybody else got some junk heads?

 

They are all over craigslist.

 

Only guy in my area wants $600 for his. I told him he was smoking crack and that I could get brand new aluminum heads with valves and springs for that much.

 

I just picked up a set of 561's that look recently redone. Im planning on throwing them up on craigslist for $300. LT1 stuff is getting harder to find.