hello...just got back from flowing another Chevy 250-292 big chamber head I have been working on....Very surprised with exhaust flow-not much work and GREAT results so far.... this test what performed on a SF600 Super Flow Machine located in Nashville area at Revolutionalry Performance Machine, LLC.....
this test used the PES aluminum Bot-In exhaust port plate(it raises the floor of the exhaust port).....I was very surprised how these plates worked with how the port was enlarged-here are results....tests Done for racing performance only...
@.500 lift 57% = 180 cfm
@.600 59.5% = 188 cfm
@.700 61.5% = 195 cfm
@.800 62% = 200 cfm
use 316.3 for factor- (ie, 316.3*.57=180)
I also tried without plate
@.500-800 58% = 184
mmmm interesting huh? and very little chamber work done.....
tests continue
the PES bolt-in Intake head on my 292 drag project is ...(194 head)
264 cfm @ .700 lift Intake
177 cfm @ .700 lift Exhaust
these plates work wonders!!!!!!! ...seems raising ports works very impressively on these heads just like most performance heads-start by looking at Performance V-8 heads and see what these heads look like.......Ever seen an Allen Johnson Solid SBC head?
Lee
