sprayedenali

iTrader: (11)

anyone ever done this? just wondering what your results were.....

garygnu

a 5.7 has a 3.898 bore .heads that big probably have too big of valves for that bore .

sprayedenali

iTrader: (11)

its a forged iron 347 FWIW, 3.905 bore

sprayedenali

iTrader: (11)

and yes, with the 2.080 intake valve that is a concern, but I spoke with WCCH and they said since the heads im looking at are the smaller chamber version I "should" be fine... he wouldn't say with 100% certainty pretty much just to cover himself I think, but it sounded like it would be good to go, as far as clearance is concerned.

and if I do get these heads and the don't work on this 347 I could always put themon the 408 in my truck!!

ckpitt55

iTrader: (4)

It'd be a dog down low. You give up a lot of port velocity without the bore size to justify running something that big.

sprayedenali

iTrader: (11)

Thos is a strip only car, so drive ability and part throttle performance isn't a concern.

JPH

iTrader: (2)

Yes, has been done several times. Use a single plane intake for optimum results.

sprayedenali

iTrader: (11)

Awesome, do you have any results or info? We're these the WCCH Edelbrock heads specifically? I'm happy to hear the valves won't be making an early acquaintance with the cylinders!

bww3588

iTrader: (49)

The valves will be close. You could probably see the same results from a smaller port head with some 2.02 valves or so.

garygnu

if the valve get to close to the cylinder wall it will hurt port flow.

sprayedenali

iTrader: (11)

As long as it will physically work in happy!

If the flow/power isn't there... Well... Where there's a pill there's a way!!

JakeFusion

iTrader: (7)

Lingenfelter's head on the LS1 was a 250cc port. They did ok.

AFR 225 Small Bore heads had 2.08" valves as well and they did ok too.

I think it's not ideal, but it'll fit and it'll work. If you spin to 7500+ it would work for you nicely.

Ed Curtis

Really? Are you sure?

sprayedenali

iTrader: (11)

Care to elaborate?? I'd tend to respect your opinion!

Ed Curtis

Because of marketing, people talk only port volume and flow numbers. There's a TON more to making real horse power with cylinder heads than just those two items.

miami993c297

iTrader: (6)

Are you really going to give a lesson here Ed???

If so, I need to grab a pack of 6 super cold, and will be ready for a little entertainment!!!

Christian

sprayedenali

iTrader: (11)

so are you saying that these heads will be a good selection or should I go another direction??

427zm

iTrader: (9)

Dang it guys! If the 245's aren't too big of a port for the LS1 bore, than why the heck not go rectangular port w/ small bore LS3's from Mast or Ballistic Speed? They flow ridiculously well, and if the 2.08 valves aren't too big, then what is the negative here? I know cathedral has port velocity that is tough to beat, but the flow of the rectangular port cannot be touched by the cathedral. I really get the feeling that small bores are pushed as much b/c tuner shops can't tell their customers for sure what kind of gains to expect. So, it makes it easier to tell their customers' "don't look at the small bore LS3's, than "let's try it and see". That said, I guess as a customer I would want to know what power a new heads setup would make.

Ed, Martin@Tick, or another guru here, teach us please. Help make sense of the valve shrouding, port velocity, and flow numbers. Being that an engine is an air pump in its simplest form, the more air you can flow through it, the more power it should make.

In theory. Help me clarify that statement and put it into reality.

JakeFusion

iTrader: (7)

Rectangle port heads have a different CSA.

CSA is what matters. Not port volume. That's why the Lingenfelter heads do well with their 250cc port and 2.08" valves on stock LS1s. Hell, their flow numbers are atrocious as well but they make power and torque.

CSA = cross-sectional area. You can make power and torque with a big port if it keeps velocity up.

Ed Curtis

In a word Christian - no.

Remember the grief we both took from the "gurus" on here with your original LS6 combination? Blew up a lot of the internet folklore with your results so no, I won't be doing any explaining of anything on here. Besides, there is Speedtalk and YellowBullet for unfiltered information.