Crowley

A.S. 5.3L S2 heads .. anyone know what size valves Jay uses???

Called .. no answer so I left a message ....

Emailed as well ....

He told me to use 7.35 pushrods with these heads (unmilled) .. well there was too much play and it bent a valve ... not sure what size they were ..

thanks,
Crowley

KGSloan

i know the intakes are a custom valve at 2.04. i believe the exhaust is 1.57, but i'm not 100% sure on the exhaust.

Louis

iTrader: (7)

That will not result in a bent valve Gary. What exactly happened?

bigdsz

iTrader: (1)

I think the exhausts are 1.575". Jay also told me to use the 7.350's.

scalemaster

iTrader: (3)

if there unmill then u might need the 7.4 and they might be the 2.02 /1.57

Brian2001SS

iTrader: (1)

I am using 7.400 lenght. He new my set up and sent no shims as well. I have read that a batch of new heads had to be milled to bring the compression back up. I thought I read the cnc shop had the seats to deep in the heads throwing the compression off. Is this the reason for the shorter push rods?

mike m

iTrader: (6)

Jay might have done some back cutting on the valve. Get in contact with him before buying an off the shelf valve.

John02SS

iTrader: (47)

Brian,
Can you eloborate on the info about a newer batch of heads being milled due to the seats being too deep? Mine are in the process and I already have 7.4 PR's and don't want to have to buy a shorter length.

Crowley,
Jay is pretty good at returning calls, maybe the holiday weekend is causing a delay. Good luck with it and keep us posted at to what turnes out.

bigdsz

iTrader: (1)

I just got a set of 5.3's supposedly with 11 to 1 compression. With that compression ratio are the heads normally milled? Can I tell from looking at them if AS has milled them?

I am concerned that rumor has it that a run of heads had the valves seated too deep. If that is true then you would need a shorter push rod. My heads are supposed to have CC 978 valves. is there any way to tell that is what they are other than checking the pressure? I know Jay uses 977's for the most part, I'm assuming that they are the same length as OEM and 918's.

under_construction

iTrader: (1)

The valves are 2.04's but they are made (cut down) from a larger Rev valve, maybe a 2.05 or 2.08. I remember my heads were waiting at one point for them as the first batch of cut down valves were machined incorrectly.

Best source would be AS for the replacment probably. Hope that helps.

mike m

iTrader: (6)

john 02ss theres no need to worry about that, there were 3 sets of heads that had to get milled extra, those heads were done over 3 months ago. fyi those heads are on cars and have dyno'd and run great.

John02SS

iTrader: (47)

So the 7.4 PR should be fine in a clean up milled head. I think we are looking at a 5 thousandth mill that would yeild 11 to 1 compression. Thanks for the info fellas!

bigdsz

iTrader: (1)

John02SS, I wish I was as optimistic as you about using the 7.4's. I want to but Jay specificly told me to use the 7.350's. He said that some guys had used the 7.4's without problems but he did not reccomend it. Comments?

Brian2001SS

iTrader: (1)

I new someone would clear that up. Sorry to scare anyone.

But why would Jay recommend to use shorter pushrods on some 5.3's? Is that due to the cam?

bigdsz

iTrader: (1)

If I remember correctly after market cams have a smaller base circle so logically you would need a longer push rod. The reason for the smaller base circle is sothat the over all lobe size will be reduced. I wish this thread had a different title so more would jump in.

destroyerSS

iTrader: (2)

i have A/S 5.3 stage 2.5's Valve size is 2.055 & 1.57. I was told to run 7.4 pushrods. FWIW jay told me he would have used 2.060 & 1.60 valve's if i had a smaller cam {231/237 598-595 Also i have comp 977 springs. I think he only uses 977 springs for the stage 2.5 & 3 Hope this helps

bigdsz

iTrader: (1)

Destroyer do you have 11 to1 CR? Thats what I'm supposed to have along with 978 springs but i'm not positive about anything since the only paper work I got was the flow sheet. I guess I should consider myself lucky I've heard of some guys getting the numbers written on the heads or nothing at all.

destroyerSS

iTrader: (2)

My CR should be around 11 to 1 maybe alittle less cause i did not have anything taken off the heads {milling} Why did you get 978 springs? Are your heads a stage 2 or 2.5?

bigdsz

iTrader: (1)

DestroyerSS I got the Stage 2. The reason that I got the 978's was that I went to the Comp web site and looked at the seat pressures for the 977's and 978's. 977's have 155@ 1.850" and419@ 1.195". 978's have126@ 1.850"and 368@ 1.250". To me the 977's were stressing the valve train and over kill. Jay perfers the 977's. Also I'm only going to be running a .56x lift cam.

With 11 to 1 compression are you saying that the heads are slightly milled, it was my impression with the 5.3's you could get that CR without milling? If they are milled how much would that be?

















destroyerSS I got the sa

Scoobie

iTrader: (8)

Im running shorter pushrods with Jays heads, Mine are making power. Mike, do you think mine were one of the 3 sets? Thanks for any info.