disco192

Anyone ever heard of running SBC valves on an LS1? Im talking standard 11/32" valve stems. I friend of mine has a 383 built in 99 and the valve retainers wont even fit over the valves for his new springs. Is it possible that they put in SBC oversize valves because LS1 didnt have any available at the time.

Obviously they cut and replaced the valve guides and seals, thats a given. Anybody ever heard of this?

Thanks,
Stu

Cal

iTrader: (1)

It has came up before on this forum. Yes, SBC valve stems are slightly larger than Gen 3. A better question is why would you want to do it? SBC valves are much thicker and heavier than LS1 valves, and weight is a bad thing for valves.

I put LS1 springs and spring shims on a LT1 once, but I had to drill out the holes in the shims larger to get them to fit. The spring retainers were slightly smaller, but close enough to fit.

LOnSLO

iTrader: (15)

11/32" valves are quite a bit bigger, and waaaaaaaaaaaay heavier.

disco192

Well this is my friends motor. These are the valves that came in the heads before he bought the car. I imagine that when the motor was made, 1999, the LS1 aftermarket did not have valves, so they just went with SBC valves. Just a thought.

So standard SBC ratainers and locks would work? With the right diameter for the springs obviously.

Cal

iTrader: (1)

Yes SBC retainers and locks would probably work, though not the best. If the locks look like they are really deep in the retainers, that's probably what they did. Normaly the lock sticks out a little. LS1's were in production in 1997, so aftermarket parts should have been available in 1999.

Maybe the builder was a just a cheap-***.

Gunnar@Patriot

iTrader: (20)

We have seen some companies use sbc valves in the LS head. I don't know what type of spring you are running, but we could hook you up with a Patriot Gold kit with our Patriot Gols prings, ti retainers and machined locks that will work on your heads and the larger 11/32" valves.

Bo White

iTrader: (59)

There are some roundy-round racers with SBCs that are runnin LS1 valvetrain(valves/locks/retainers) and I see the advantage of that because of weight savings but do not do the opposite especially since the SBC hardware is heavier and requires the same mods to the heads to make em work. Just my oppinion

SSean

Stu, if you're refering to Micks motor, I spoke with him yesterday about the matter. We have already come to the coclusion that they are 11/32 valves, and have springs on order

Sean

disco192

Yes, I am referring to Micks motor. I dont know why you would need special springs unless there arent retainers available for the springs you are running. Its just a retainer and lock problem as far as I know. You also might need to get retainers that set the install height of the springs down.

Of course I dont know the parts you are working with, so Im not sure exactly what the install heights are gonna be. He was just freaking out last night when I talked to him and was trying to get some more info for him.

Its good that you guys have everything figured out as he had no ******* clue what was going on (not your guys fault, he just doesnt really understand how springs, retainers, and locks work)

SSean

I understand, I tried to talk to him a little yesterday about it, but he took off pretty quick. Basically, we ordered PRC dual replacement springs which requires use of the factory locks. The actual valve stem is a larger diameter than the stock LS1 and LS1 replacement valves, so the stock locks would not work. The springs we removed from the head are larger in diameter than the LS1 replacement springs also, using larger retainers and locks. The old locks would not physically fit into the new retainers, nor would the old retainer fit into the new spring. After taking a few measurements, I belive the springs might have been comp 977's (or something similar) The inner diameter of the spring is .700, so we needed to find something comparable, that will support the cam he has, that will fit the old retainer/lock combo We ordered comp 977 springs, and are looking into a few other options as well, just incase those dont work. I left a message for him to call me so we could go into more detail, but have not heard back yet (I think he's still at work)