Crusty66 said:Wanting to build up my big block - I got talked into what I now think are the wrong heads, I think the CR will be too low.
Here's what I've got already
Edelbrock E-street 110cc chamber
KB-Silvolite 4.125" 17cc dome
looking at a mild hydraulic roller Comp Cams Xtreme energy XR258HR
Duration .050 in 206.0 ex 212
Lift .510 .510
Timing (seat) In Open 23 In Close 55 Ex Open 66 Ex close 18
Lobe centreline 110
Intake centreline 106
With a .040" gasket & zero deck height I come up with:
static CR of 9.0
Dynamic CR 7.7
Fuel here is 95 RON
So will this work? these heads have hard seats & heavy valves, so will only take the mildest of hydraulic rollers - I DIDN'T KNOW THIS-.
ok,first issue!
I build mostly big block chevy engines, and those particular cylinder heads are MORE than adequate if your going to use a mild cam similar to the one you listed, better flowing heads will be wasted as youll never be able to reach near the potential with that mild of duration and lift.
http://www.jegs.com/i/Edelbrock/350/504 ... 1800263821
Id surely select a dual plane intake and a bit more lift and duration, on the cam but without knowing the car weight, rear gear ratio,transmission used tire diameter and several other factors I can,t really guess at the best match
now I would not be thinking your working at a huge dis-advantage due to the use of those heads, those heads are rated to flow over 309 cfm at .600 lift and with a bit of port and bowl clean up flow more, most SBC engine in the 383-406 displacement range WISH they had heads that could equal those flow rates.
you might want to stop and think thru the cost of rebuilding and modifying the current engine Vs upgrading some or even most of the components, in some cases youll find you can buy new components or even a crate engine or short or long block assembly, at a cost level similar to what all the parts and machine work might cost to refurbish the current engine.
http://paceperformance.com/search.html? ... &go=Search
http://www.cnc-motorsports.com/short-bl ... -deck.html
http://www.edelbrock.com/automotive_new ... /50459.pdf
http://edelbrock.com/automotive_new/mc/ ... reet.shtml
you might find the links useful
viewtopic.php?f=69&t=2165
viewtopic.php?f=69&t=7722
viewtopic.php?f=69&t=9930