Griff

Not necessarily maxed, but starting to fall out of the powerband. I think you are leaving some HP on the table in the upper rpms. You could always just have it reworked and flowed out to about 900-950cfm.

In reality though, it is probably working fine with the cam that you have, since its on the mild side for a 540ci. You might notice more of a difference if you change the cam.

Rebel_Heart

Jim Valako is the man when it comes to porting aluminum heads. He did a great job on my Dart Pro Ones. I'm running 1050s on my 540s.

302Sport

i keep hearing jim v for the heads and bob madera for the cams. i guess if i have bob grind me some cams, i can change the heads next year. when this all started i wasnt planning on making any changes until every oso member told me i have the wrong cams haha. good thing i have you guys helping or i wouldve been back on the slow boat to china.

302Sport

heads are at the machine shop now for new valves and springs. while there i think i am going to have them milled .040 for some comp.

jeff1000man

If you mill the heads that much, the amount of comp you are going to gain is not going to offset the amount of potential lift you are going to loose.

I stopped reading this thread and just glanced at it, but you are saying that they are only 8:1???

Sounds like those were blower engines that some took the blowers off of. IMO Those things won;t even get out of their own way.

Best thing you can do is just leave them alone until you can afford to take them out and put a higher comp piston. If those are at 8 or 8.5, then they are a dished piston.

With that little comp, even after you deck (ruin) a set of heads, you will have to turn way over 6000 rpms to get any decent amount of HP.

If you deck those heads, you are going to loose a lot of valve lift that you really need to get those engines to breath.

These are my thoughts, you might talk to Madera, or call Dean Gellner or Eddie Young, all are contributors on this site, but from what I have glanced at on this thread, sounds like you are going to waste a lot of time and money.

Everyone is at PRI show this week.

If you want a quick fix without pulling the engines, just leave your cams alone and find a set of closed chamber heads. That will give you a lot more bang for the buck. Save your current heads for when you are ready for a more thourough build.

Parts are cheap, machine work is expensive, and trying to make something do what it was not designed to do by spending money on machine work is just going to cost you double in the long run.

Good luck though.

302Sport

thanks for the input jeff. motors are on the floor right now and not in the boat. heres what pistons are in there.

http://www.jepistons.com/Products/139521.aspx

picklenjim

That would be more like 9.5:1 with those pistons and your heads.

jeff1000man

139521 540 4.500 4.250 6.135 9.780 1.520 9.8 9.4 9.1 -3cc 644 0.030

With a stock square port (118) CC Chevy head. Basically off of any 502, you have a 9.4:1 +- comp ratio.

That engine will make some decent power. Leave the heads alone. Stop what you are doing with new springs until you pick your cam so you can make sure your springs are correct for the cam.

There is no reason you can't make 650HP+ with the correct cam shaft and an 850+ carb.

Talk to Madero when he gets back in town this week after the show.

Then make sure your heads are set up by a reputable shop. Madero will cut the cam to whatever RPM you want. He will also set it up or your boat so the torque curve will be in a good spot.

If I read right. you are running dry exhaust. Those engines can make all the power you want. Don;t waste any money on getting them ported or anything like that unless you are going to do it yourself. Safe your money and buy a good set of CNC'd heads over the summer or next season and those Madero cams will wake up.

Good luck with it.

If that is the piston you hvae, then you are on the right track.

jeff1000man

if you are going to upgrade intakes, the go ahead and buy the dominator flange. Use the adaptor for your 850's. It will act like a carb spacer in the interim, and then when you get some more cash, upgrade to a 1050 and put the 1" spacer on there.

You will pick up a few RPM's

TxHawk

iTrader: (2)

Make sure it has plenty of fuel at 9.5:1 with iron heads.