valves 2.080/1.625

'stage 3 porting'

28 inch test pressure thest bore 4.030

100 - 72/60
200 - 140/117
300 - 190/144
400 - 228/158
500 - 252/178
600 - 256/187
700 - 248/186

my cam's lift is 560 btw...

whatcya think?

lt1 cast alum heads btw

 

 

Agreed

 

Did they install new seats or just put these huge valves in? low lift idicated good flow cuz of big valve, after that it looks like its a restriction.

 

Not very impressive especially with these large valves.

 

Better than stock, but lacking when compared to Lloyd's. His usually flow 270/192 @ .600". Those numbers seem to drop off fairly early.

 

Here are the flor number for the LE stage 2 heads:

.2 136/102
.3 192/137
.4 238/164
.5 265/183
.6 271/188

I guess we're starting to use these as a baseline. For his price you can't beat them. Yours seems a little weak compared to these, especially for a "stage 3" job.

 

yeah, these are no LE heads, i would have loved to get those but these were a good price, so i went with these...


dunno why u guys are so suprised with the valve sizes... they are what they are.... could have gotten 2.100 if i wanted, but these were already built, so i just got'em

 

I think they are suprised at the #'s with valves that size.

I posted my head #s yesterday and they are only about 10cfm lower than yours and my heads have 1.94 and 1.60 valves.

 

Why we are so concerned over the valve sizes......

First a LT1 casting needs a new seat in the head for anything over a 2.00" valve. So "cheap" and a valve head diameter over 2.00" shouldn't go in the same sentence.

Second valve size relates to curtain area. Basicly the area around the valve at .XXX" lift. So a 2.00" valve @ .500" lift sees 1.570 Sq/in or area. You can only get so much thru a certain size hole. Depending on how close it is to the bore and if it's canted or not then plays a role in it too.

Bret

 

While I'm playing on the old man's computer...

Bret is absolutely right on the 'cheap' comment. Before you run those heads I would highly recommend having a reputable shop check out what has been done - it may save you a great deal of trouble.

Good luck,

-Phil