I Need GM Valve P/N's

[Dennis H.]

I have a set of 461 heads to build up and have 4 NOS Intake Valves and 4 Exhaust Valves that I'm trying to figure out what I have.

Exhaust - 1# 329275 GR 0.297 size is 1.50

Intake - 1# 3989085 GR 0.296 size is 1.94

I tried to look up this in my GM parts data base but did see these part numbers. Any idea what I have or can anyone tell me the correct GM part numbers for replacement valves for a set of 461 heads.

While were on the subject, should I even worry about using GM valves or go with something else? If the 8 valves I have will work thats half the money I don't need to spent on valves.

[Joe L.]

Re: I Need GM Valve P/N's

Dennis-----

This is a lot more complicated than one might think. It's further complicated by the fact that the valve application depends on what year and engine application which we're talking about. It would seem like the 1.94 and 1.50 valves should be interchangeable between any heads which originally used that valve size. But, for some reason, there are differences.

I believe that the valves that you mentioned will work for your application, regardless of what it is as long as these are the correct size valves (i.e. the head size is what your heads are machined for). However, if you tell me the SPECIFIC application, I can tell you if GM says that they will work for the application.

[Dennis H.]

Re: I Need GM Valve P/N's

Joe

This is for a 1965 327 350hp engine buildup. The engine is a 870 block and the heads are 461 small valves. These heads will need hard seats installed but I'm not sure if I want to go with large Int and Ext valves. I have been told you run the risk of damaging a set of heads by installing large seats and I don't want to do that. Maybe just go with large Ext valves????

[Joe L.]

Re: I Need GM Valve P/N's

Dennis-----

I would not enlarge the valves, even if you are building an L-79. The valve size you have should work just fine and, perhaps, better than the larger valve size. You don't really need to install hardened valve seats, either. You can if you want to, but you don't really need to.

The GM #3989085 intake valves are a successor part number to the original valves used for your heads. They should work perfectly according to me and according to GM. The current part number for these valves is GM #14075641. They GM list for $18.51/each.

The GM #329275 are not a direct successor to the exhaust valves that GM originally installed in your heads. GM says that the direct successor is GM part #6263778. However, I think that the GM #329275 will work ok for you. To be sure, check the stem LENGTH against an original exhaust valve. If they're the same as I expect, then these will work just fine.

The current replacement for the GM #329275 is GM #14095451. This valve carries a current GM list price of $21.95/each.

By the way, the GM #6263778 valve which GM says is the correct current part number for your application has a GM list price of $45.00/each.

Another alternative for you might be to obtain a high quality set of aftermarket, stainless steel valves. You might find that a complete set will cost less than the 8 remaining GM valves you need.

[Duke W.]

Re: I Need GM Valve P/N's

Sealed Power (Federal Mogul) makes very good OE replacement valves that are every bit as good as GM and a lot cheaper. In fact the parts GM sells are probably the same - maufactured by F-M.

As with Joe I don't recommend increasing the valve size. The difference in performance potential is marginal, but as with any OE head, pocket porting/port matching with multiangle valve seats is the best single performance improvement you can make.

Also, there is no need to install hardened valve seats on a Corvette road engine. The risks of a seat falling out is greater than the risk of valve seat recession from lack of TEL, but the myth just won't die.

Duke

[Joe L.]

Re: I Need GM Valve P/N's

Duke------

Yes, the Federal-Mogul valves are very likely the equal, if not the same as, the GM pieces. The Federal Mogul parts are as follows:

intake----V1612
exhaust---V1199