Jimmy P

iTrader: (177)

I have Absoulte Speed 5.7 heads. I am the third owner of these heads. The guy I bought them from didn't even know that they were 5.7 heads, he thought they were 5.3 heads. Can anyone tell me how I can check this? I think you put them flat down, and check the lengh of them, right? If so, what is the stock lengh? I have tryed the search button, and read through atleast 30 different topics, and can't find what I am looking for. Anyone? Thanks!

Beast96Z

iTrader: (21)

You can get the measument of a stock head, but you need to be sure of the points in which the people are measuring from so yours will match. You also need to use a dial caliper and not just a ruler. Your measuring thousandths, not inches. You could also have someone cc the chambers to get an estimate, but I believe measuring the thickness will get you closer.

Jimmy P

iTrader: (177)

Thanks for the reply.
I was thinking about that, but I dont have a stock head around. I was hoping someone already did this and had some numbers that I can compare to, and from there see how much was taken of mine. Thanks

Bo White

iTrader: (59)

I PMed ya back but here it is. I measure the thickness of were the small head bolt goes through the head, I have seen stock heads go anywere from .980"-.990" here before milling, most common measurement is .982-.988"

ArKay99

iTrader: (1)

I have some stock 853 heads. I will be going by the shop tomorrow and will measure those for you. Hopefully that will help.

Jimmy P

iTrader: (177)

Thanks for the replys guys. Bo gave me the number I need. Thanks Bo!

bigdsz

iTrader: (1)

There are two measurements that you can check, You will need a digital caliper. The first measurement is the head bolt boss closest to the exhaust port, for unmilled heads it should measure 1.615". The second measurement is from the head deck where the head gasket goes to the top of the head where the valve cover and its gasket are attached. That measurement should be 4.75" for unmilled heads. It's tough with AS heads which is what I've got because everything is Jay's special sizes like the valves being +.070" for instance. You need shorter push rods to account for that. Also the valves are hung way out on the seats for better flow , but that makes P/V contact much more critical.

Jimmy P

iTrader: (177)

What size pushrods do I need with my 5.7's? I have chromemolly pushrods right now but I have no idea how long they are. They came with the car.
Thanks

Oh yea, I have JE pistons with 3cc valve reliefs, so hopefully piston to valve clearance wont be a problem. I am using a stock height Felpro gasket just to make sure.

Beast96Z

iTrader: (21)

It depends on how much they are milled. Most get away with 7.350's, but a pushrod checker is the best way to go. They sell them in Summit or Jegs.
On a diffrent note, I wonder how the deck measurment would line up with AFR heads? My heads are supposed to be milled, but I get the .985" measurment on the small head bolt hole. hmmm......

Jimmy P

iTrader: (177)

Thanks, I will look into that pushrod checker.

Well, I think the info that Bo gave us only works with the GM castings. You can ask Tony what the measurement would be on a unmilled AFR head, and go from there.

bigdsz

iTrader: (1)

Jimmy P, I gave you the measurements you need to check. After you do that then we will be able to discuss pushrod length and your valve train geometry.Jay at Absolute generally used valves with longer stems, and with a smaller base circle on a aftermarket cam shorter push rods are necessary.