JLC

Hello all,
I was wondering is it possible to stuff 2.100" intake valves and 1.600" exhaust valves into the 852/706 heads?

I want to keep the small combustion chamber since im running the stock 5.3 bottom end (9.5:1 I believe for the 99 models) my main concern is valve clearence as far as quinch and intake head vs exhaust head inside a 61cc head.

I plan to fully port the heads and the ls6 intake as far as I can. (Will be done by a shop)
I have been doing some research and have read that the port and polished heads (706) can flow just under 300cfm
Im only going to be shoving nitrous through the heads at the moment but planning for a twin turbo set up in future.

Any and all input is appreciated
Thank you
Jessie

KCS

iTrader: (20)

Yep. Just need larger seats, which any machine shop should be able to get.

JLC

So I dont have to worry about valve clearence with the pistons? Being its going from 1.89 intake and 1.55 exhaust to 2.10 intake and 1.60 exhaust?

96capricemgr

iTrader: (1)

don't bother. If you really think bigger is better get some L92s and use a chisel to clearance the bore so the valves can open.

KCS

iTrader: (20)

I was just talking about getting the valves to fit in the head. They could fit in a 5.3L bore and clear the pistons depending on the cam, but with nitrous and eventually a turbo, what's the point? Why a 2.10" valve anyways?

JLC

I was told at a younger age that an engine is like an air pump so the more air it can flow the better so I figured why not go up to 2.10" in. Hot rod magazine went with 2" in. In 706 heads on a 5.3. And got tremendous results.

Another reason I figured 2.10" in. Was look at the camel hump heads off of a gen 1 sbc compared to regular heads. Due to chamber size and valve size its like flushing a toilet vs draining a sink. (Bad analogy, but see my point?)

Im obviously not the wisest guy when it comes to volumetric efficiency or flow rate by any means. hints me asking you guys.

Thanks for all the input thus far
Like previously stated any and all input is appreciated cant learn without trying or asking questions.

96capricemgr

iTrader: (1)

leave the car alone, put a lock on the hood and give the key to someone else.

KCS

iTrader: (20)

Well, you have two opposing views where a bunch of guys believe smaller 2.00" valves are better and then you have guys that believe in cramming in the largest valve possible. Both are pretty adamant in their beliefs.

I'm one of the latter. I want the biggest valve possible, but 2.1" may not have enough clearance from the bore in a 3.78" bore. I would probably go with a 2.040" max.