Valve ?'s

[Anonymous]

Is there any alternative for bigger valves, besides stainless steel? I have a D7 head, so I have the 1.75 intake, but I'd like to get a bigger exhaust valve. I'm trying to keep on a slight budget, so I don't wanna shell out the close to $100 for the SS valves.

The tips on the valves out of the head are slightly mashed, so I'll probably have to get new ones..

I'm building a 250 for my Ranchero, I'm leaning more toward low end and gas mileage than top end HP...

What's the advantage of SS valves, is it just the weight savings?

Thanks

 

[CobraSix]

I think they hold up better and are less subject to wear and pitting associated with normal valves. But I may be pulling that out of my arse.

Slade

 

[CZLN6]

Howdy again 6t8:

Stainless steel is more resistant to the stress of heat and time. SSI valves are chrome plated stems and stellite tips, again better to resist wear. I'm not yet sure that SSI valves are Stainless. Azcoupe has them on his site for $7.95 which is a pretty good price for drop in valves. The last set of 144 intakes I bought, for my exhaust, were $9.00 a piece from Kanter's

In truth, for your stated goals, stock valves of 1.75" & 1.38, with a three angle valve seat and a 30 degree backcut on the intake, would be most cost effective and a significant improvement over stock.

The small stem diameter of our valves at 5/16" limits options. V8s and other candidates are 11/16th or 3/8th. These valves can be accomodated with larger id valve guides or machined down, but with out appropriate relieving to unshroud the combustion chamber low rpm performance would be marginally improved. In fact, smaller valves and higher velocity may have an advantage. It is certainly cheaper and easier.

Just my thoughts.

Adios, David

 

[Anonymous]

So ya think the stock exhaust valve size would be ok for me? Even with a slight cam upgrade and a header? I plan on having the 3 angle and backcut done...

If it needs valves afterall, I may just get the FSPP ones.. I dunno how much cheaper stock replacement valves would be... Anyone know any prices for stock replacement valves? (1.75 / 1.38)

I took the head in yesterday to get tanked & magged.. kinda funny little side story... the guy at the machine shop told me they were gonna stick it in the oven, and I asked him if it would mess up the seats (I remember I had some 351 heads cooked, and they said it would mess up the seats & guides.. different shop tho), I told them they were hardened seats(It's a D7 head) and he told me that they aren't that "the only hardened seats are the kind that you have to put in" I told him it's a '77 head, and he still stuck with what he said.. Kinda irked me... almost makes me wanna go to a different shop... well as long as they don't TRY to sell me hardened seats.

Seems a little ignorant on his part... just from logic don't you think when cars started to have cat converters with the fill pipe restrictors(so ya couldn't put reg gas in it, only unleaded) that the factory would start putting hardened seats in the heads? I know most of the v8 motors started doing this in 75-77...oh well I guess I have to consider this guy stands around building small block chevys all day..
:roll:

 

[Anonymous]

PAW lists replacement Manley O.E.M. valves for the small six. 1.53" intake ($7.95), 1.65" intake ($4.49), 1.75" intake ($5.49), 1.38" exhuast ($5.69)

 

[Anonymous]

Sorry to spam but I bought the big later intake valves and the early 144 intakes (to use for exhaust-they are almost 1.5) from Manley - just as recommended in the Falcon Performance Handbook. At the time I had been waiting for a backordered set of SSi valves and my engine needed a rebuild unexpectedly- but then they showed up just in time.

Anyway- new in box, 1 month old- and I was going to e-bay them but it would be less hassle to sell them to you if you want them. the lowest price option i saw listed in this thread was 5.50 each so I could let them go for 4.50 each if you are interested.