Vortec
 

Now im not very knowledgeable on the vortecs but a friend of mine got a set of heads off of a newer motor and they do have the centermount valve covers, the intake has the 2 inside bolt holes that are straight down and the exhaust ports run pretty much straight out, unlike old style that went over that hump. But what i would really like to know is the valve sizes on them because he said they have small valves like 1.83 or something about like that on the intake. So if yall could help me out and maybe tell me what it could have come off of that would be great. And also what makes a sbc 350 a "vortec"?? Thanks

The "vortec" heads are centerbolt and come on 96 and later trucks. They also have the straight down intake bolts, they use a vortec specific intake. they all have 1.94/ 1.60 valve sizes and are great performance upgrades for TPI cars and L89 cars. Teh combustion chambers are a small 64cc so a compression hike is common if they go on some small blocks with 76cc heads. They have tremendous flow though, the most of any cast iron chevy head.

I believe the Vortec is just a different head design, the rest of it is just a run of the mill 350. But I could not tell you what the head specs or differences are.

Well see thats the thing, it does have the straight manifold holes and the smaller combustion chamber but i put a 1.94 valve up against the intake valve and it was smaller than the 1.94 thats what i dont understand.

looks to me like you have some 305 heads that were on 96 305 chevy trucks....they came with 1.88/1.50 valves. The chamber size is still 64cc or maybe even 58 cc on some 305's...also a good performance head on a typical 350.....only because the compression is raised over stock

So do you think they would be good to use on a .60 350 with 12.5.1 pistons??

what cc head was the 12.5 to 1 compression ratio at? 64 or 58 or 76? if that 12.5 to 1 is rated at a 64 or 76 cc chamber then your compression will be sky high. those heads woiuld work ok on a basic 350 around 9 to 1 compression, rv cam, and decent valvetrain. What cam are you using with that 350 your building? the valves are only 1.88/ 1.50's in those 305 heads, not the most desireable for a performance buildup....most people use 2.02/1.60 or at least 1.94/1.50. I guess it all depends on what you want that motor to do.....a big cam and those heads wont work well, and i dont think they will like all that compression unless you plan on running race gas.

Well the pistons are 12.5.1 pop ups, so with the 58 cc or maybe 64 then it will prob be around 14 or 15 or something im not sure but its not my motor its a friend of mine and he was just askin what i thought and told him i would find some stuff out about it. Im not sure what the numbers are on the came but i know its got a 106 lobe sep. with like .347 lift intake but im not really sure, that was the same thing that i said when i saw the vavles and the cam. I really think that he should use 2.02 or maybe even 2.05 but he has alot of other radical **** but he is mainly old school and doesnt really know much about the vortecs.