brian_rs/ss

so i have a 230/234 .600/.610 112 lsa EPS grind on its way to me right now. was going to do a port job on my 799's and be done with it. then my tuner showed me these heads, and i really like the numbers. we already have the figures crunched and what not if i pull the trigger on them. but i just realized that the l92 heads will breathe a lot different from the 799's. soooo should i change cams, if so where do i start? no idea what duration or split i should be shooting for. lift still needs to be 600+.

http://www.mastmotorsports.com/2010/...+-+Bare&id=354

it will be topped off with a FAST 102/102. and i really want to take advantage of those flow numbers.

brian_rs/ss

just found this cam from thunder racing.

231/247 .617/.624 113 LSA

they have it listed as a 3-bolt ls3 cam. wonder if they can grind something similar for my ls1?

99 Blue Bird

iTrader: (3)

isnt the whole reason of having the large split in duration on cams for the rectangle port heads because of the huge valve size difference. the valves for the MAST "small bore" heads use 2.04 1.57 valves which are commonly used in CNC jobs for cathedral heads when upgrading to larger valves. so basically your just getting a square port head with smaller valves than stock L92/ LS3 heads so that they can be used on a bore size smaller than 4". so as far as needing a large split in duration i think you will be ok with the EPS cam you have coming. but maybe a larger cam could be specd out for you to take advantage of the square port itself . someone correct me if im wrong.

brian_rs/ss

ok that makes sense. was thinking about the raptr, if i had to do something "off the shelf"

236/242 .615/.615 111 lsa

only thing i'm worried about is clearance. 62cc chambers on those mast heads. i think i'd be ok but i'd definitely have to check.

garygnu

whats the flow % diff between the intake and exhaust ports?

brian_rs/ss

@ .600 lift intake is 342 exhaust is 248, if my math is correct thats a 37.9% difference.

if thats what u r asking?

MM98

iTrader: (13)

Just a heads up!!! When I sent a PM to Mast about these heads vs their 215 cathedral head, I was told they use a 2.08 intake valve.. I was baffled because the 2.04 advertised on their website was much more appealing for a stock cube motor.. I sent back a pm about what he said vs what their website shows, but have yet to hear anything back.. I have since changed direction in heads, but you might call to verify what size intake & exhaust valves are actually used.

brian_rs/ss

aight ill have my tuner call, as i'm in afghanistan at the moment. that very well maybe be a deal breaker.

are the exhausts still 1.57?