I was wondering.....I'm finishing my heads and was looking at maybe getting some big valves for them. What goes into putting in the big valves and how much will it cost?

 

the vavle seats have to be ground out for the bigger valves, 195s 155s perferably. and have to sure they are seated and and have proper springs on them and set to the right install height. and the valve may need to be un shrouded

needless to say by someone who knows what they are doing.

 

Vince....there you go again. You killin me man. You missed the big question. HOW MUCH??????? Meatloaf.

Hey did you get the pics???

later bud

 

if you furnish the valve and springs i would say about 300

and yeah i got them, look pretty good man.

 

My machine guy did it for $175(three angle valve job)+ an extra 20 for material removal. The valves were about $180 through Jeg's. But you're gonna pay for a three angle valve job anyway, so one way to look at it is I paid an extra $200 to get the bigger valves.

 

Are you wanting to spend the extra $ to have the seats cut out, and new ones pressed in?

If so you're probably going to end up paying anywhere from $100-200 for someone to remove & press in new seats.

Valvejob cost will usually depend on complexity (time, duh). If you want a more "normal" 3-4angle 45deg job, then you'll probably end up paying $125-175. As far as valves go, you can pick up manley race flo's for around $170 I believe. They're not nearly as nice as a Ferrea 6k series however, but the ferrea's will cost you around $220 i believe.

 

So there's no extra work for the machine shop??? Just cut the seats a lil bigger? What size should I go with?

 

LT1 seats are extremely hard and I've had machine shops break bits multiple times (they charge you about $50 if the bit breaks). If you want to go big like me (2.02/1.6) then the seat will have to be replace w/ a larger one. This usually costs in the area of $250 around here in Orlando. the 1.96/1.55 will fit in the stock seat and save you a little money. This is the wiser choice for most unless your heads are flowing above 255/185cfm w/ stock-sized valves in place. At this point, I've gained 10-11 cfm w/ 2.02/1.6 @ .600" when compared to 6-7cfm w/ the 1.96/1.55. Before anyone blows a head gasket, these w/ back-cut race valves on thoroughly worked heads. After some more bowl work, valve angle work, and some more flow-bench time, the heads flowed 271/204 @ .600", which was only about 2 cfm above the .55" numbers. The problem w/ stock LT1 castings is that even w/ port work they flow-stall badly anywhere above the .53-.55" area....hence the GM-designed LT4 Hotcam has .525" lift

 

What are you trying to do exactly?

You don't need any more than a 2.00/1.56 set in the LT1 stuff to flow 27Xcfm peak. You can run 2.02/1.60 valves if you want on the stock seats, but I'd just stick with 2.00/1.56's. If you're wanting to run a larger valve like a 2.055/2.080, then yeah, you'll have to cut the intake seats out, but its not worth the $ for most stuff IMO .

 

Thanks Phil...that's what I needed to know. So the 2.00 / 1.56's huh. Thats what I'll go with then. Shouldn't cost much more right? I got the Hot Cam Kit with the springs and all that already. Will I need to change tHose? I wouldn't think soo...only if I change to a bigger cam right?

Thanks

 

S.J.S., I forgot the 2.00 supposedly fit the stock seats. I've heard different things from different people (I'm not a machinest) but I do think I remember that. The valvesprings in your kit should be fine for most. Believe it or not, the LT4 sodium filled exhaust valve is incredibly light for its price. I'd just caution you to stay away from the FERREA valves....they tend to be heavier than most and would promote more float than lighter weight alternatives. Supposedly FERREA has new gun-drilled valve stems as an option though.........

 

thanks.........all the searches I did on this post says the biggest you should go with are 2.00 and 1.56. They also say the gains are real minimal and money should be spent somewhere else unless your trying to "squeeze" every last bit of HP out of them. So still a toss up.

 

Hey I've got an idea. If you have already decided not to go with the larger valves you should upgrade your springs. The guy that set up my heads said the springs that came in the HOTcam kit were too weak. Those springs are made for the LT4 cam, not the LT4 HOTcam. Springs would be quite a bit cheaper anyway. Actually the guy that did my machine work would not even install the supplied springs, he made me get some more.

John

 

Thanks John.... hahahha. thats all I needed to hear..KACHING... more scripts. Nah. Thanks for the info. Just another thing to add to the money pit I guess.

 

In my 1997 Camaro I'm running 2.19" intake valves and 1.88" exhaust valves.

-Dave C. '97 Z28
454cid Gen VI Big Block