head questions
head questions I've got my heads off and laid them next to the ones I was going to swap on to switch the rockers over and thats when I noticed they have some differences
....
anyone know whats up with that? how come this other set is so much shorter and has some casting differences? did they make changes in different years or somin? if I use them will it effect anything other than the length push rod I'm going to need? they don't look like they've been milled since everything in the combustion chambers seem the same. heres some numbers I took off them, I'm not sure which ones are the important ones:
top inside: F215 350
center inside: 12551561
sides: 13271
ideas? TIA
....anyone know whats up with that? how come this other set is so much shorter and has some casting differences? did they make changes in different years or somin? if I use them will it effect anything other than the length push rod I'm going to need? they don't look like they've been milled since everything in the combustion chambers seem the same. heres some numbers I took off them, I'm not sure which ones are the important ones:
top inside: F215 350
center inside: 12551561
sides: 13271
ideas? TIA
They did make different head castings. 561, 374, 643 are the only ones I know of. The last two are the desireable ones for porting. The top center (12551561) will tell you which heads you have. What is the casting number of each head?
the 12551561's are the ones I want to put on and 10207640's are the ones that came off my car and are the taller ones in the pic. would the height effect anything other than the push rods? is it fine to swap these heads on? I never thought the differences in casting numbers were this big..
Yeah, I believe the 561's are the '96-'97 heads. You should always check for pushrod length when swapping heads.
edit: and the 640's are the ones that came off my '96z ??
I was going to using the marker on valve method but now I bet the 7.125 push rods will be in-correct for sure and might as well go ahead and get a length checking tool. ...but..the castings changed over the years but didn't the push rod length of 7.2 stay the same? if so how could that be with the difference in height I'm looking at?
edit: and the 640's are the ones that came off my '96z ??
edit: and the 640's are the ones that came off my '96z ??
Yes, 7.2" is the stock pushrod length for all year LT1's.
Use the sharpie method to measure for proper pushrod length. You will need an adj pushrod and either a solid lifter or a test spring.
Oh, well maybe the 561's are from only '97 cars, I don't know. I had 561's on my '97.
Yes, 7.2" is the stock pushrod length for all year LT1's.
Use the sharpie method to measure for proper pushrod length. You will need an adj pushrod and either a solid lifter or a test spring.
Yes, 7.2" is the stock pushrod length for all year LT1's.
Use the sharpie method to measure for proper pushrod length. You will need an adj pushrod and either a solid lifter or a test spring.
LOL makes me wonder.. I guess I'll buy the tool from some one else cause I'm not comfortable NOT checking PR length. 
