lsjeep52

Ok, so I recently bought a set of LS1 heads off a buddy of mine SUPER cheap. They are CnCd with 210cc intake and 76cc exhaust. Valves are 2.02/1.575. Dual springs with 375lbs/in and max lift of .680. Closed seat pressure is 135lbs.

Im installing these on a stock bottom end 4.8, and I was gonna buy hardend pushrods along with SLP 1.85 rockers. I dont want to tear into the cam, and since I got the heads cheap, Id rather spend the extra on some push rods and rockers. My question is this too much seat pressure or can I install and not have to worry?

ls1 1990 VN

If your cam is standard, Then that is too much spring!

03EBZ06

Doesn't sound very high to me. 135/370 at 680 lift, no big deal. If they are shimmed, maybe you could remove a shim.

lsjeep52

If I remove the inner spring, it should come down to 105lbs on the seat. But is that enough for the 1.85 rockers or will they float?

lsjeep52

Bump for more suggestions?

01ssreda4

iTrader: (96)

I run more pressure then that without issue.

lsjeep52

so stock cam with 1.85 rockers i should be fine?

vettenuts

iTrader: (4)

Valve springs are fine and I would run them as is. I would investigate 11/32" pushrods, hardened pushrods are not stiffer they are made to run with guide plates. These will help control pushrod flex with the stiffer springs.

lsjeep52

do they make 11/32 pushrods for the 5/16 cup size of the lifters and rockers?

Old Geezer

iTrader: (3)

Manton. They can make most any you need.

vettenuts

iTrader: (4)

Yes, as stated above, Manton can make them. Do a check and make sure they will fit in your setup although I haven't seen anyone run into an issue yet with GM heads.

lsjeep52

Ok thanks guys, im gonna order the 11/32 dual tappered to 5/16 manta pushrods in 7.400. Hopefully i dont need a different length by changine out just the rockers, but ima get the length tool just in case. Im gonna run how the springs are first, but how will i know if they are too stiff?

vettenuts

iTrader: (4)

Springs are fine. As for the pushrods, Manton uses overall length (OAL) not gauge length. Do if you use an adjustable pushrod to measure you can either directly measure OAL if you have a caliper long enough or add 0.017" to the gauge length measurement from the adjustable pushrod.