I'm ready too put oversize valves in a head thats ported and don't want to blow it working with my machinist we got our wires crossed he ordered valves for a 340; 1.88(I),1.60(E) instead of 1.70(I),1.44(E) as in "Slant Sickness" (Hotrod November 200).So today I called him to check on things and he says "hey those valves just touch each other, won't work" Well what came out of this miscommunication might be a good thing, he said "you know what I would do is use the 1.70 for the intake and the 1.60 forthe exhaust,I can make that work,it will take some grinding to eliminate shrouding". Now I trust him, he's done great work on the short block but we both agree it would be better to colaborate with someone(s) who has tryed this or has a opinion about it.

magicalbus@hotmail.com

340 valves are about .200 too long. They will most likely need to be cut and regrooved(expensive) I optioned for 1.94/1.50 sbc stainless valves(which are cheap), but you need to use 11/32 guides. They measure about .100 longer, but once installed, they only sat about .075 higher. The intake was turned down to 1.75 as well. I used big block mopar valves, and offset Crane retainers to get the proper installed height. Hope this helps.

sschultz@telusplanet.net

Thanks for the info. the retainers were a good tip and it sounds like I can go stainless now just curious what are you useing for intake and carb?

magicalbus@hotmail.com

I have a Clifford 4bbl intake, and a 600 holley carb. I also have a Racer Brown cam, 254 at .050, and just over .500 lift. I can post some pics of the head if you are interested. It's been professionally ported. The one nice thing about running sbc(sorry for the swear words, lol)valves, is that there are numerous retainers and locks for any application. I purchased my valves off Ebay for under $100.00 for 16. (Manley pro-flow)

Another option is small block Ford. They are the correct length and you can get a 1.70 intake that is a "drop-in". The exhaust has to be tuned down a little to get the 1.50. For springs and retainers, 340 parts are also "drop-in". I don't remember all the part #'s but that is what J&M used on my head. Dennis


aschumers@aol.com

Dennis--

I think MP springs you're talking about are:

P4286813--IH:1.65/1.70"--single/damper--OD:1.39"--lift range:.390"-.450"

retainers:

P4452033--chromoly--8 degree lock--3/8" valve stem--for single spring

Koller Dodge has @ about $3 a pop:

<A HREF="http://www.kollerdodgeparts.com./">http ... s.com./</A>

other small block MP springs that pertain to /6 usage:

P4120249--IH:1.67/1.70"--single/damper--OD:1.50"--lift range:.430"-.500"

P3614542--IH:1.67/1.70"--dual/damper--OD:1.45"--lift range:.500"-.610"

P3412068--IH:1.68/1.70"--dual/damper--OD:1.46"--lift range:.520"-.620"

hope this helps
---Red


Torr66@aol.com

hob bout 318 valves springs retainers etc. will they drop right in? with the seats machined of course


wtzupdoc@pmcol.com

Dennis, I think the ford valves are 11/32, which would mean you still need different guides and retainers.

Just thought I'd post a pic of my head(slant 6 that is)with the 1.75/1.50 valves. There is room between the valves, but any bigger and they start to get to close to the outside areas.

My 2¢
Used the following parts for a "big valve" head:

Late style air passage small plug head cut 0.100", gasket match ported, pocket ported, and chambers semi-polished (35-37cc chambers).

Ford small block valves, Manley #S-1670 Intake, #A-1669 Exhaust, cut to length to match stock valves (0.080" off exhaust and 0.100" off intake)

Comp Cam's springs #995-12, retainers #740, .530" P/C valve seals, and 10° locks. Guides fitted with 11/32" solid bronze guides and cut to fit springs and seals. Valve spring pressures @ 150# closed and 330# open (.520"±).

Stock push rods and rockers, with geometry correct for position of the rocker on the valve stem, and the push rods with 2± threads showing on the adjuster.

Expect an easy 6,000 rpm with special Comp Cam (redline @ 6,200± max!). Expect to shift at 5,800-5,900 with 904 auto. Guessing that it will go through the lights @ 5,500± or a little less on 26" tires and 3.91 axle.


sgw041454@aol.com