bigredexpress99

iTrader: (15)

I have some 5.3 heads just sitting here, and am going to be porting and polishing them, and have the chance to pick up some stock ls1 valves for 25 bucks or so. I know I would need new seats put in, but is it worth it to up the size of the 5.3 valves in the head to 2" and 1.55", or is there more involved? Is the valve the same length as the 5.3 valve, and same stem diameter? or would new guides have to be machined in as well?

How about valve springs for these heads, will a set of comp or crane valve springs drop right in like a normal ls1 head, or are the 5.3's any different?

Any help, or to just point me in the right direction would be great!!!!!

Okie5.3

iTrader: (1)

i was talking to a local machine shop (they supply austin coil with parts) where i live about doing my heads and they said they i wouldn't have to replace the seats if i wanted go to a larger valve that they would re-grind the seats to accomodate the larger valve. the exhaust valves are 1.55 already, and the 5.3 valves are the same stem length and diameter as the 5.7 and 6.0. as far as springs there are a few options PP, Comp, Crane, etc...that will drop right in. going too large on the intake valve (2.05/2.08) would probably cause shrouding and actually hurt more than help. this shop said for what i wanted done the difference between doing an outright purchase of some heads from somplace like PP, TEA, TSP, etc.. and having them do it, would only be a couple hundred.

bigredexpress99

iTrader: (15)

yeah, I thought but wasnt sure if the exhausts were the same size, but I am pretty sure the intake is smaller on the 5.3's so uppin them to a stock 5.7's 2" (im pretty sure thats stock) was the basic plan, on top of the porting and polishing. I DEFINETELY did not plan on going bigger than a 2.02, but if I can pick up these stock ls1's for next to nothing them I will just go with them.

Any one else? Thanks.