SBC valve help!

[casual]

Found out that a few people are using SBC valves in there jeeps! I found 2 sets and need some help deciding which is best!
They are both 1.940 is diameter, both 4.910" in length, .341" valve steam diameter..but 1 is a 12 degree dish while the others a 7 degree dish..Both are undercut and swirl polshed!
Which would be the better one to use? Whats the difference is the "degree of dish"? Also is there any reason to go to a 2.02" intake valve? "stock sized exhaust valves will be used"

12 degree dish
http://www.summitracing.com/parts/MIL-45005-8/
7 degree dish
http://www.summitracing.com/parts/SUM-V8000-8/

Any advice on which to use? I am building a semi-stock rebuild..,.60 over , ported head, bigger valves! So these seem to be a cheap upgrade...Might do a simple cam, probably a Comp 68-201. I will be using stock springs, retainers and everything..Only upgrading the valves!
I plan to use these exhaust valves,
http://www.summitracing.com/parts/SUM-V8008-8/
Anyone see an issue with doing this? Also anything else I'll need to run these valves besides reaming out the guides to 11/32?

[SilverXJ]

You won't gain anything by going to larger valves. Swirl polished and back cut, will help. Also, going to a larger stem diameter will not help with valve train weight. You may take a look at Valves for the Magnum V8s. They are only slightly larger, same stem diameter and very close in length to the stock valves. They are available in swirl polished, ss, etc.

[casual]

Thanks for the tips..Ya I figured there wasn't much to gain, especially since I won't be trying to pump out to much power..
I'll start searching for info on valves!

[dwg86]

I used 1.94, 1.50 sbc valvs in my stroker because the guides were bad, and several valves were bad. It was going to cost about the same to use the sbc valves or have the guides and stock valves replaced. I stepped up the guides to 11/32, and used stainless undercut sbc valves. Advantage of the sbc valves...1) They are cheap and 2) you open yourself up to a world of different valve springs to use.

If your valves and guides are good, I would stay with the stock setup.

[SilverXJ]

Yes, if your valve guides are bad it would be more cost effective to use the SBC valves. However, Jeep valves are 4.837-4.852" in length and the SBC valves are 4.910" in length. I wonder how much that would effect valve geometry (.071"-.058").

[rammit11]

I just finished up setting up my head with the small block chevy valves. I went with the 1.94 intake and 1.5 exhaust ( I don't remember which exact ones I used off the top of my head other than they are undercut and swirl polished), they didn't require much work to fit them to the head and best of all I ended up being able to run stock push rods with preloads between .115 and .120.

[SilverXJ]

Isn't that a bit much preload?

[rammit11]

The quote I got from my machinist was actually 100 to 140 . I don't doubt what he says as he has built quite a few 4.2 and 4.0 race engines with a very successful outcome.

[rammit11]

just talked to my builder , the numbers he gave me are for the amount left in the lifter till it bottoms, not the actual amount that the pushrod is pushed into the lifter.

[SilverXJ]

What is the preload then?

[rammit11]

hi, got all the answers today on how they checked the preload. It ends up around .05. Long story short it comes out to .03 to .06 just measures it from a different point.

[6TIME]

Keep in mind that if these valves are dished/tuliped on the underside of the valve head, it will increase the chamber volume and lower your compression ratio.