Who all is using this setup? I know its not optimum due to shrouding, but I want to use these until I get a large bore motor. Are there more valve clearance issues?

 

wont fit 2.05 is a large as you can go.

 

Actually I know for a fact that people are running this combo....

 

Well if they are they are not as efficient as a smaller valve there is no room for anything over 2.05 of you go bigger you will lose power I have heard this from more than two head porters.

 

really? cuz Brian Tooley @ TEA suggested 2.08 valves for me on my stock block since i'll be running a largish cam, and the heads will eventually see stroker duty and be bumped to a stage 3 anyhow. i won't lose much power at all on the stock block afaik. where are you gettin your info from?

 

I agree with you CT . I got a set of 225's comin' from AFR. Jason told me they would work fine if I got the 2.08's. I told him it was a 395 stroker (stock bore). As we all have discussed before, the 15 degree valve angles make shrouding less a problem than with the traditional SBC. I would venture that a 2.08 would be less shrouded on the stock 3.900 bore LS1/LS6 than a 2.02 would on a 4.00 bore 23 degree SBC. I am open to new ideas, though. I too, am interested in the "2 head porters" opinions and just who the 2 porters are.

 

Am also confused on the statements here. The post said that there is no room to go bigger than 2.05, then says there is room, but it won't put out the same or less power? Which is it?

 

The term "room" is being used loosely. You can use it in terms of physical distance between the cylinder wall and valve, or as in making any sort of power if you were to use it in a stock bore.

 

I ran 2.08 1.600 on a stock bottom end a couple years ago. The heads were from Race-Prep. One of the first 450rwhp h/c cars.

 

I was told by ARE that you can't run a 2.08 valve on stock bore.....

 

Thats funny considering they have been doing it for years. Infact I am pretty sure they were the first to do it

 

A 2.08 will fit w/ no problem a 2.10 should fit a 3.910 in a tight squeeze.

 

A 2.080" valve is too large for a stock valve seat. Maybe that's what you guys are talking about. It will fit in a stock chamber, but it's close.

 

No we are talking any size valve seat the only limiting factor is the stock bore. I will bet money the highest flow numbers are with valve sizes of 2.05 and smaller however the original post was planning on switching to a larger bore down the road which would justify going with a 2.08 valve IMOP.

 

Yeah I know that a 2.08 will physically fit, I was just asking what other things should be considered on a stock bore when running a valve of this size. Anything major?

 

going from a 2.02 valve to a 2.08 valve and adding a 90mm setup took me from 475rwhp to 507rwhp on my stock bore 395 stroker

i really doubt i got 32rwhp just from the 90mm setup

my heads flowed a lot better with 2.08 valves even on the 3.9 bore (i picked up around 15cfm at .600 lift)

 

how much do you want to bet?

 

I'm with Kumar. There is no doubt in my mind that on the original SBC, it would be a useless addition on the stock cast iron heads. The valve angle of 23 degrees shrouds the valve at a much smaller diameter than the 15 degree LS1/LS6 series, which is what we are talking about. I also believe that this shrouding would take place on the majority of heads that were designed 30 years ago or so. But again, our LS series is a "clean sheet of paper" design, modern, or whatever terminology you care to use. I have learned that the C5R heads are only 12 degrees. When I discussed this with AFR, they still were of the opinion that angle milling was not a desirable thing to do to the 225's I have coming. Maybe if I was in a road race environment at 6,000 RPM+ for a long period, maybe. These heads are VERY good right from the factory. I am still amazed that this engine can make this kind of power with so little work. I don't even have underdrive pulleys, and the engine is totally stock still. With an LS1 Edit tune, Flowmasters, no cats, 160 stat, LS6 intake, and a blackwing, I went from 13.80's @ 102 to 12.80's @ 110. I busted my butt on a traditional SBC that I had in a 1985 IROC-Z and it was a 383 with a cam and 2.02 heads with mild port work, 11:1 comp. 1000cfm TB headers, LPE "Box" intake and larger runners, i.e., a lot of mods. I couldn't get over 104 in the 1/4. My C5 has the "wimp" stock cam that has what, 198 duration on intake and 204 or so exhaust? These heads must flow like a mother! Car Craft had a Z-28 a few months back owned by a guy from Illinois I think, and at the time he had the fastest cam only LS1 in the country. It ran a 10.90 @ 125 or so as I recall. Has to be a great set of heads stock. Probably why it took someone of even AFR's abilities 7 years to make 'em better. I am not sure if just putting in a 2.08 with no port work would be a good idea or not, though.

 

i have run my 2.08 valved heads on stock motor stoke and bore, and it did just fine, on a 100 shot i made 549 and 579ft torque on a mustang dyno, with a very very wide torque curve and no none zip zilch drivabilitly issues.. and now they are on my new stroker but i havent dynoed that yet, but im sure it will be pretty high na and with the 300 shot it should be even higher "after dynotuning of coarse" now, if only they would make sticky roads........

 

I'm with you on the sticky roads!! I know you guys will think this is nuts, but here goes. Years ago, a buddy of mine got the bright idea of mounting a windshield washer motor just inside the front grill on his 4x4. Anyhow, my buddy got a great deal of fun while driving in town (he did this on purpose) as when he got caught at lights (again, on purpose) and people would use the crosswalk in front, he would activate the washer motor and PRESTO! An instant wet T-shirt contest !!!! Back to the topic at hand. This crazy idea has been in the back of my head for the last 2 weeks or so, about the time I got my Yank 3200 installed. Translation- instant NO TRACTION! My crazy idea is as follows: Why not take my old friends idea a step further and use it to our advantage! That's right! A windshield washer pump in front of each rear tire!!!! You got it- sans the washer fluid and filled with........ Traction compound !!! Well, I told ya it was crazy, but it could work, maybe?