hello I have been using this forum for months researching and for tech questions and entertainment. but what would like to know now i cant find with the search tool.

i am building a early 80's carbureted 350 for a off road only home built mud machine.a jacked up solid axle swaped 2 door isuzu trooper,456 gears ,40" tires.3/4 ton axles,1 ton drive shafts/TH350-NP203.

the engine is nothing realy serious. sealed power coated flat tops ,1.94 heads ,air gap dual plane,HEI,comp camp 262 4X4 cam,chinese roller tip rockers.

I cleaned up the heads today after work and instaled new valve springs and seals.

the valve guide bosses are machined for the press on valve stem seals. when i took it apart in had umbrelas on the exhaust valves {i understand, from reading that is common] and the press on ones on the intakes.
all of the valves had a small oring in a groove on the stem under the keepers.

I instaled Viton umbrella seals on all the valves and did not instal any of the little orings on the stems,i also junked the [i don't know what there called} valve spring hats or shield deflector things,that were originaly under the retainers.

the heads have cast iron guides.

i am wondering if i will have a problem running ubrella seals on a head that is machined for the pess ones? and if not instaling the tiny oring is a problem? also can i leave that spring hat thing off?

I am a professional marine diesel mechanic. sell them,instal them,rebuild them. but i have no gasoline engine background.A engine is a engine when it comes to putting it together, but little stuff like this,i need some help with,thank you chevy guys.  

The rubber seals near the valve lock groove can be left out, and the spring "hat", as you called it, can also be left out.

The umbrellas are just splash protection - they will do their job equally well regardless of the shape of the guide boss.

The person who assembled the heads before had a method to their madness when using 'positive seal' seals on the intake valves only. Of course the intake tract has a vacuum in it so oil can more easily find its way into  it. Especially with iron guides having more clearance than bronze guides this may be more prevalent.

I guess if you don't want to reconsider that's fine but just realize after the engine has been ran if there is build-up or some blue smoke oil entering the cylinders from 'up top' is a possibility.  

I am reconsidering now.

it has dawned on me that i have double valve springs ,and they  may interfere with the umbrellas.

the springs i removed from the head were also double springs of the same size i replaced them with. but that does not guarantee it was rite to begin with.

the umbrellas i used are not that large i may be allrite with them. they are sort of small not like large black ones i am seen in the past "about 15 years ago"

they are a teal grean color,if that means anything.

I am not over thinking this small detail.i have plenty of other things going on.
I am just in need of a education on the subject.
So please fire away.

a easy solution is to just go ahead and tear 'em back down  and put the press on's in her.but i am liking the idea off having better valve guide lubication on a engine that is going to see constant abuse. daily over heatings and plenty of wide open throttle.

it will be used a weekend here a weekend there every few months or so. rode hard and put up wet.  

Well, you won't find an aftermarket cylinder head with anything but 'positive seal' type seals. Of course, all of those heads will have bronze guides as well, so maybe that's not the best indication.

PM me your email address and I will send you an excerpt from literature I have.  

The teal color means the umbrella seals have a different material and heat rating. Good aftermarket viton seals of varrying diameters are available. Measure the ID of your inner springs, then the OD of your seals. You need to have at least .010" clearance, the more the better.  

Not to go way off topic but can a flat tappet cam and tappet lifters be used in a 89 305 block that was meant for roller lifters (they have taller lifter bores and yes i do have longer push rods). I heard they will be okay as long as your cam does not have a smaller  base circle than stock but I would like some input so i can know before i build. I know the spider and lock plates can be removed and so can the end cover plate for the cam as the tappet lifters and cam don't develop end thrust, but the taller lifter bore is my main concern. Aftermarket (taller) tappets are available, but i already have my new lifters (short bore lifters) and don't want to find out by trial and error if they work in the taller bore.  

You did go way off topic.  

Has anyone heard of or tried using the umbrella seals from a 289 Ford..? They are softer rubber and will fit inside the valve springs. At least that is what I was told by an engine builder. I'll know for sure when I pick them up tonight.
And, when replacing with umbrella type seals should you also use the ring on the stem too.
I'm redoing the heads on my '73 Vette which I think were done at least once before because the intakes had umbrella's. They also used the rings. I want to put umbella's on the exhausts too. Hence the dilemma of buying sixteen and making sure they fit inside the springs. Double springs.  

I will send you the same stuff as the thread author if you want it. It's some excerps from John Lingenfelter and David Vizard and should address your questions.

PM me your email address.  

Thank you kindly and PM sent.
And those other brand seals did not work. Too big for one, didn't fit inside the springs, and not deep enough for two to set themselves over the guide boss. He did say 289 or 302 but couldn't remember to be sure. I would think 302's would be the same but it doesn't matter. Going with some Fel-Pro's made for GM's. Unless your article tells me otherwise.
Thanks again.