pele000

Does anyone know how many castings GM made for the LT1/4 head design? If so can anyone post pictures. Thanks?

96capricemgr

Two for the irons I think 3 for the aluminums and one for the LT4, one for the L99 which is a 4.3L version of the LT1.
What info are you looking for? Pictures will do very little good, actually the worst as cast ones are the best from a porting standpoint because they have enough material for the porter to work with. Tell us what you want to accomplish and we can be of much more help than pictures would be.

pele000

I purchased a set of heads and were told they were off a 97 lt1 car. They have a lot better design than stock 95 heads. They have a better oil return and the casting is square and not rounded in the center portion of the heads on the intake side.
I will get the part # off of them Mon. They are getting more porting now.

96capricemgr

If that is what they are they flow more in stock form but are much less desirable as far as porting goes. Thin casting limits the porters ability to play.

As far as being "a lot better" they equal the flow of the 94 irons so whomever fed you those lines about how great they were was looking to make a sale. They probably know what I am telling you too since it is common knowledge on all the forums. They can be ported somewhat but not to the level the early castings can be.

pele000

The part # on the heads are 12551561. Are these better, worse, no diff than 95 castings? Are the spec the same(cc,flow,runners)? Thanks.

97WS6NY

the 561 casting is the LEAST desireable casting for porting, I had them as well and was gonna send them to lloyd until he said they were sh*tty for porting.

pele000

Thanks for the quick reply. I have already bought them. They are ported w/lt4 size stainless steel valves and good springs. They look good, but that kinda sucks? Any idea about flow # with 561 with a stg 2 port and polish job w/lt4 vavle train?

shoebox

Don't worry. Your 561's will be ok. They're just not the optimum casting for porting. Shouldn't your port person give you flow numbers when they are finished?

pele000

I bought them ported off of this sight. I am having them massaged a little more, and I am matching them to my intake. I should have them flowed. I paid $600 for them, and I thought that was a fair price being that the valves and machine work would cost almost that much..??Any thoughts? Did I get beat?