Okay, I'm going to be installing an LT1 cam soon, and I want to replace my leaking valve seals at the same time. There are quite a few places selling Viton valve seals on eBay for like $22 after shipping.

Are these all pretty much the same as long as they are Viton seals? Is there an advantage to "metal-clad" seals?

Also, what size do I need for a stock 305 head? 11/32" by .500", 11/32" by .530", 3/8" by .530", etc.?

 

Fel-Pro p/n SS72527 for the intake and Fel-Pro p/n SS72877 for the exhaust. Those are the factory fit viton valve seals (positive kind, do NOT require machining). Available at most auto parts stores. I got mine at Advance Auto (Parts America).

 

dude, why are you going to bust your *** putting in an lt1 cam? installing a cam is such a mission... the moment you put it in, you're probably going to say to yourself "damn i never want to do that again", so you might as well do it once and do it right... go for something bigger man, or just hold off with the cam instal till you can match some heads with a cam and an intake and go at it all at once. just my .02 because ive been there, done that, and when i was done, i was like, "bro i never wanna do another cam instal again"... 3 weeks later i land on an even better cam for my hsr, and i had to install that sucker. do it once, and do it right. the lt1 cam isnt much of a cam to wanna go through the hassle of swapping cams.

also... i wouldnt stick an lt1 intake on a 305. not to bash you or anything, but (ill try to find the link) someone i know did that and told me it was a waste of time and money. they actually went slower in the 1/4 mile. you only really gain an advatage over tpi with the lt1 intake on a 350. stick with the tpi setup and go with the comp cams 502 cam. get yourself some LTR's, port your plenum and get a larger manifold base, install some headers, port out your heads and a shift kit, and you'll be running mid to low 14's depending on your driving skills. i know that it's hard to get money when your young (the 87 in your sn must be the year you were born), so don't blow it away on crap like an lt1 cam and stuff that'll make you go slower... and if you're building a 355, you might as well just junk the 305 and go all out on the 355. honestly... i dont know why people put money into 305's, unless they do it correctly. ive seen 305's hit 11's with the help of a twin turbo setup... but i bet if those snails were on a 350, or even a 402/427, it'll run in the 10's. good luck to ya man, and i hope you don't take my reply in an offensive manner. take care bud

 

try some tefelon seals, comp makes them

 

I've heard Viton are better than Teflon. I'll check to see what kind of positive seals the local parts places have. How much are these seals usually?

Anyways, the reason I began on this LT1 intake project is because I thought I was going to be the first (which I know I'm not now). The reason for the LT1 cam swap is because it was very cheap, and should still give me about 30HP over what I have now, seeing as its slightly more aggressive than the T-5 305 cam which has 25HP more than my auto/305.

I don't want to buy a $200 cam for this motor and then have to buy another one again for the 355. I'm not sure when I'm going to get around to doing the 355 yet. My plans were to do all of the bolt-ons possible and then swap them over to the 350. The reason for the LT1 cam swap, as I said, is that it is cheap and will give a decent performance boost. The cam is the only thing that I've done to this motor that I won't carry over to the 350.

I've been considering a twin turbo project because I could do all the fabricating myself, and doesn't look like it would cost *that* much as long as I do it all myself. But I'm not sure how realistic that is seeing as there will probably be a ton of other related things that need to get upgraded, etc.

With the lightly hand-PnP'd LT1 intake, cam, headers, hi-flo cat, stall, possibly new gearing, self-ported heads, and a nice chip, I'm hoping to be in the very low 14s or high 13s.

 

Viton is NOT better than Teflon. Unfortunately however, the Teflon ones require the guides to be precision-machined to either .500" or .530"; they will not work on stock guides. You're stuck with Viton ones if your heads are stock in that area. So, just use the Fel Pro ones, they'll do fine for the application at hand.

 

Well, to answer your last question. 11/32" x .563"

Auggie

 

The Viton ones are that size; 11/32" x 9/16" as Auggie posted. Stock. The actual numbers don't really matter, the word "stock" will get the job done at the parts counter, or even better, the part #s themselves listed earlier, which are the ones you need.

 

"Stock" as in stock size, but they will be positive seals, whereas the OEM originals are not, correct?

I want to make sure they don't take up too much room on the valvestem (the more clearance the better) since I'm going to be going to a cam with very close to .480" lift.

 

From the factory, O-rings and umbrellas were typically used on the older cars. Newer engines and head castings for forms of the positive seal, such as the Vortec head.

As I have said in another post, just take the heads to a shop and have them mill the bosses down a tad, just to be sure.

 

My "84" L69 305 had positive seals, o-rings, oil shields and steel retainers on the intake valves. The exhaust valves had umbrella type seals (not worth a sh*t), o-rings, oil shields and rotating retainers. Two summers ago I installed the int. positive type seals on the exh. valves and haven't had any oil smoke on start up. Man and did my oil consometion go down. I just did a set of "993's" and there was rubber all over the place when we removed the valve covers.

Auggie

 

So let me try and understand this... If I run Fel Pro SS72527 on both the intake and exhaust, I will be fine? Do I need to buy the o-ring style seals also, for the top of the valve stem, or will these positive type be good enough all the way around?

 

You only need 1 form of oil control.

The ones you inquire about are the intakes. Run them on the intake. The exhaust part #'s IIRC are special for higher temps.

 

Well, all I can tell you is what I do and there maybe those that disagree. I use Seald Power positive type seals (XUA-MV1888) on both the intake and exhaust valve guides (84 Z28) with oil shields and no o-rings. You have to use the oil shields to stabelize the valve spring on stock setups.

Auggie

 

Okay, lets bring this topic back into light... again...

I bought Felpro SS 72527, the intake set, and they look great...

I had to special order the exhaust set, Felpro SS 72877, and they don't look right... they don't look like positive style seals. They are nylon with rubber in the middle, they almost look like umbrella type seals... Here's some pictures of them.









So on the left is Felpro SS72527 (Intake) and on the right is Felpro SS72877 (Exhaust Optional High Temp). Do they both look like their positive type or did I get the wrong thing. The exhaust just looks like a umbrella type seal, which isn't what I want. I wanted Positive type seals.

 

Okay... It's confirmed, the Felpro SS72877 is an Umbrella Style Seal. I remembered the set of Heads I had in the garage (L98 Heads) and check the seals out on them. They do not "connect" to the Valve Guide, they just slip over it quite loosely, and it fits more tightly then the intake side around the valve seal.

So I will be returning the Felpro SS72877, and purchasing another Felpro SS72527 (yes 2 sets of Intake Seals) and gonna try that and see how it goes. Wish me luck guys.

 

anyone know if this felpro #ss 10058 for exhaust valve seals are positive locks and will they work on a l98 ? thanks

 

You won't need it, but good luck anyhow

Auggie

 

Planning this project too, putting it off long as possible. Keep in mind that the intake stem is under vacuum, does need a pretty good seal with older guides that have worn. The exhaust valve is seated during intake vacuum and would be more likely to have heat come up the stem on the exhaust stroke. The different seals from FelPro kind of makes sense to me. The prices they charge for them makes no sense though. Sure hate to tackle that passenger side with the A.I.R. and heater hoses/control over top.