Bob, sounds like the Big Chiefs are capable, but it also sounds like a lot of effort every season. What springs are you running with that solid cam? My cam has similar lift and I am just curious. Thanks, Craig

nice engine :apache77

thanks timucin

Wette Vette/

We ended up using the Isky 9385+ which is a tool room outer and a normal inner. Put them in at 215# at seat. First attempt was with Gold Stripes 9945 , tool room inner and outer, in at 250# at seat. From what I can tell the Big Chiefs are probably worth 30-40 hp over a 360 at 6200? I have them because they came with package. Would I put the bucks up for new ones if I were building new motors? No. But, they do make hp. KE did some 588's like my package and made 714 @ 5000, 790 @ 5500 855 @ 6000 and 873 @ 6500. With 632 or so they should be up around 900+ at 6000? Not bad for a natural setup ( Kinsler FI). With any head I guess you would need to change springs and look at valves after 100 or so hours. If someone can figure out a way to make 850-900 hp and get 200-300 maintenance free hours life would be great!

jdnca 1

What intake volume did you end up with after porting? Those are some impressive numbers for a 360 cc head. At what lift do they flow mid 420's? curious [/B][/QUOTE]

Intake volume is 390. Heads had full CNC port and polish at Dart with some additional hand blending by the builder. 425 flow is @.800" lift.

Bob,
Did you have problems with the 9945's? I am running comp 951 pacaloy springs and they were installed around 235 on the seat and they are now (25 hrs. later) at 220 on the seat. I have heard good things about the Isky springs and may consider them when these 951's are spent. I also may just put on a new set of 951's if these hold up another 25 hrs. or so without breakage. Just trying to get some more info.
Craig

If you guys want some cool valve springs check out www.lsmeng.com they will custom make you a valvespring per your valvetrain requirments. And if you really want to spend some money they have titanium springs.

Years ago I remember alot of hype over a rev kit that was being introduced. It utilized a plate that fit below the cylinder head with springs that pushed directly on the lifter. The idea was to take some of the pressure off the rocker arm. Anybody know what became of this kit and why it hasn't caught on?

Wette Vette/

Last I heard, a head shop down by KE's was really sold on the 9945 spring and a lot of guys ran the 9945 spring in the old A boats and had very good luck. Isky swears by them. I believe they are the psi spring. They were just too much pressure for my application and Isky said I did not need them. If I were going to run up around 6500 for extended periods then I would have to go there. Might be a viable option with KE's spray bar.

I built my engine to a 604 c.i. and have had no valve train problems,the block is a raised cam 10.2 merlin,i don't know if that is for better valve angle or more clearance for a bigger cam.But i
run a .629,.639 lift with .248,.252 dur.at .050.Cam is full roller.If
you guys are running into valve problems tell me why you think
yours are failing versus what i am using.Thanks