I'm getting m heads P&Ped and if I spend $200 more (bringing the total to $600 for that) I will get them done for bigger valves. Of course, I'll have to buy the valves for like $180 more....so are hey worth the $380?

 

just depends on how fast you want to go. i wish i would have gotten bigger valves when i had my heads off.

 

I talked to like 3 machine shops when talking about further P&Ping of my already P&P'ed heads, theya ll said, you need a valve upgrade really to take advantage of the new flow. Well problem is when you upgrade to the next size valves they need tot ake the bronze seats out, mill it out and put new ones in + new valves etc etc and they all said to me, go after market.

Like ARF heads or LT4's, you would be much happier. So maybe if you can do it for 300 more, then thats awesome. My places were talking 1000+.

 

A problem with bigger valves from what I hear from some mechanic buddies is valve shrouding, cant exactly explain it well, ask someone on here thats pretty knowledgeable, but I know its a problem.

 

You don't need bigger valve to make mild power. I am looking to make around 420-430rwhp (maybe more...hehe) with a high stall tq this year with P&P LT1 heads with 1.94, 1.60 valves.

 

What do you consider mild power? Should I go with stock valves, or upgrade to intake lift of 2.000'', Exhaust lift of 1.560''? Or higher to Exhaust of 1.600'', intake of 2.055''?

PLEASE HELP!!!!

 

I have seen as high as 450 rwhp with stock'ish valve sizes...I think he was running 1.94/1.60 also.

You would be better off getting some high-flo valves, do some bowl work, clean up around the guides, basically do a simple P&P.

I makes no sense to me to put a bigger valve into a head that still uses the stock size seats. You effectively just made it more difficult for incoming air to go around the valves than need be.

I consider my 360 rwhp/450rwtq combo mild power...

 

Who is doing the heads?

 

Lloyd Elliot....

 

I bought valves with a lift at the intake of 2.000" and exhaust lift of 1.560"......this good? How much extra HP should I see and is that all I have to change for the head work?

 

Just to make sure you realize there is a "typo"... we're talking about valve head diameter here, not "lift".

I went through this with a highly experienced LT1 engine builder (they built the quickest LT1 on the planet, and several 9-second LT1's) and he told me to go no further than 2.00I/1.56E on my engine. Said there was little if anything to be gained beyond this, because of shrouding. I'm running 500flywheel on a mild solid roller 7,200rpm 381ci, with a 300-shot of juice on top of that.

For anything of 800HP and above, it would be worth looking at going larger, depending on the specific heads you are using, IMHO