cobra marty

After playing around on the 'Engine Analysis' program and looking at all you numbers, I can come up with this:

Your 540 is pretty healthy now with 1.26hp/cid with 9.5CR, peak tq at 4500 but I would think that at 5500 rpm you haven't hit your peak hp. All this means that you have very good heads-what ever they are- and maybe a bit overcammed for your intended rpm range/goal.

Now with the 598 you can add 10% to your tq figures and I would think that your heads and cam would be pretty darn close to perfect. But your tq will be in the 750-765 range.

Change in CR from 9.5 to 9.8 is worth 15 tq and hp across the board.
Change from 1.7 to 1.6 rockers only lose 10 tq and hp but reduce lift by 0.030" which might really help the valve train/springs/lifters last longer.

Unless the 598's are free, I would keep the 540's. Why go to the tall deck for very little change. The 'EA' program has the Brodix BB-2 fully ported heads as about the best power producers.

I hope that helps a bit to confuse you some more.

Turbojack

Cobra- I was also noticing that. I was going to build a 572 this winter but as I ran the numbers on desktop I saw I was going to increase my low rpm HP & torque (bravo killers) & gaining very little on top end. Since I am not needing any more low rpm torque I decided it was waste to spend the money.

My AFR's are to be here friday, They shipped when they said they would first week of Oct.

KAAMA

Marty, thanks a million for checking into that for me. When comparing with your "engine analysis" program, I have sort of came to the same conclusion when comparing to my Desk Top Dyno---lots of torque down low with the 598 which is good, but is it really worth the small gain you get on top at about 5400-5600rpm??? Sounds like TurboJack has found the same thing. I also called Bobby Daniels' shop and they ran my flow numbers and found about the same thing. JimV felt the same way about the head size for a 598 as well. He felt the heads I have now would work well with a 598. But I think I may just stay with the 540's. It just doesn't sound like it's worth all the fuss going to tall decks and all the expense and aggrivation. I'm going to work on super tuning my engines and remove the hook from the hull of my boat and have the last 4 feet of it blueprinted. Then possibly going with some 2" IMCO's lowers or something. I think if I am going to find any speed it will be from the things I have just mentioned.

Thanks to everyone who has contributed to the input within this thread----you're help has just saved me some BIG $$$ and aggrivation and that makes me smile.

Turbojack

I left out one small item. I was working with stage 4 procharger. Motor being blown made the HP about the same but max was at a lower RPM. I guess if I went with a wilder cam I would get more HP but I figured I would just save the money. At least I will not have the kitchen remodeled now.