Please Help No R.P.M

[Kevin Crane]

Hope someone can help me out here ! Built BBC468 10-1 motor and it hit's a wall at4300! Heavy 75 Tahiti hull 19'6" Spinning a A impeller Pump is fresh Berkley With Loader And new wear ring. Motor is 468 TRW forged ,Balanced , Stealth Intake,Holley 850,All MSD, Crower Cam Intake: Duration: 311 / Lift: .578 Crower Spring's ,Crower Lifter's , Crane Roller Rocker's , No Headers Yet Just Log's . Boat has about 1/4 " hook which I will take out this winter . Have been told that this cam might be to big any one have any ideal's ????????? Thank's Kevin

[HammerDown]

Ya should be getting more R's than that.I'll tell ya my engine combo...468 Chevy,Comp Cam # 11-314-4 Lift 550/t554,Dur.232/237,Lob cen.110.Comp.springs.Crower roller rockers Also using TRW pistons 270 dome at 9.75 comp. with oval 049 iron heads bigger valves,bowl blend,flowed out 116cc.Stealth intake topped off with a 715 vac.Holley.Mallory dual point Dist.36 degrees total (thats were it made the most rpm) Bassetts O.T. Berk. Aggressor A. On a good air day no baffels the motor spins up to 5400 rpm,baffels in hot humid East Coast weather I'll drop 51-5200.Daytona 21 footer.Don't think that little bit of hook would drag ya down that much? What is the state of tune with the motor? Total advance,jetting.I would think the 850 is way big,but the item that's hurting you the most is those log exhaust...ya cant make power unless ya get that air out as well as in!
[This message has been edited by HammerDown (edited October 10, 2001).]

[77charger]

sounds low to me im runnin a bbf429 with a 248@50 .590 lift 108 cntr hydraulic cam,10.5-11-1 comp.stock dove heads ot headers,19' boat,a impeller,energizer pump.With baffles 4800@68 5k witout(dont know the speed there but faster).Timing is at 34 total but can bump38 with 100octane.The ot headers will help your cam choice is good,have you ran a comp check on your cylinders whats your timing set at.I would expect 5k on that set up.

[Kevin Crane]

HammerDown, Have 34 in it and I belive jet's are 82&84 plug's look good just a little dark ..Indeed log's killing me but think this motor should turn in the area of 5500. Good set of header's would give me ruffly 50 Hp. more and that would be 12 to 1300 more rpm gain if that could only work like that it would be nice huh?? It's some little thing but what that thing is I don't know !!

[Kevin Crane]

77charger, Timming also at 34 compression is fine have about 40hrs. on this motor. I was hopeing to turn around 5500 with this motor!!

[fryzll]

I have a 18.5 Challenger and my #'s are about the same as 77charger, 4800 rpm at 67mph. I am runnin a Jacuzzi w/ a A impeller (I think). It sound like you have all the good stuff. What kind of shape is your carb in? Was the cam installed straight up or advanced? I cant remember if it was MSD or Mallory but the gap between the pickup and the rotor opened up and had a simalar prob on my buddys car. None of this is probably it but hey, its my .02.
Chris

[Kevin Crane]

Originally posted by fryzll:
I have a 18.5 Challenger and my #'s are about the same as 77charger, 4800 rpm at 67mph. I am runnin a Jacuzzi w/ a A impeller (I think). It sound like you have all the good stuff. What kind of shape is your carb in? Was the cam installed straight up or advanced? I cant remember if it was MSD or Mallory but the gap between the pickup and the rotor opened up and had a simalar prob on my buddys car. None of this is probably it but hey, its my .02.
Chris

[Kevin Crane]

Carb is new ,All is new Pull's real hard but hit's a wall at 4300!!!!!!!

[custom-cruiser]

Kevin,
If you give me complete cam card or grind # and what size valves you have I can run it on a computerized dyno program and see if your torque curve is falling off early,Then i'll throw in a couple different cams and see what happens.
If anyone else is intrested I need motor type,bore,compression,valve sizes,cfm,manifold type(single,dual,blower,turbo),exhaust type,lifters,and complete cam card at seat to seat or .050 and if your cam is forward, up or back. It's not 100% real world but gives you a good idea and lets you try different combos without all the time and money,like how much hp would a superchiller give? or a different cam ect. ect. http://free.***boat.net/ubb/biggrin.gif
Currently I turn an "A2" 5500 rpm and with a little help from this program I think i'll be Knockn' on 6000.

[Beavertim]

Custom Cruiser,
Does your Dyno model have an input for turbo boost (blower boost is probably OK)? If so, could you run my engine specs? I have a pretty much stock Ford 460 with log manifolds and a draw through twin turbo setup. Max boost is 8 psi. CR is 8.25 to 1, cam specs are Intake .500 in lift 234 deg duration @ 0.05, Exhaust .510 lift 224 deg duration @ 0.05, I'm not sure of the lobe centers, but lets assume 114 deg sep. Holley 750 vac secondary with 72 jets in primary, 90's in secondary, PV's in both. Manifold is stock 429 CJ. Have done some mild porting of heads which are stock closed chamber. Intake does have intercooler (70's era design). Thanks Tim