Russ Fulp built my engine, he has also built engines for Dennis Antennucci, Dennis Daley and Matt Meritt. Russ has a very good reputation. As for rings seating in the cylinders, I don't know? A problem started early on with excessive oil consumption, like a quart every 200 miles. That turned out to be bad intake gaskets (Mr. Gasket) that I replaced with Fel-Pro's. I'm not sure that has completely solved the oil consumtion problem, I suspect there is a little blow by going on. Russ says he sets his engines up loose, but I'm not sure my rings seated properly? The dyno guys gave me no air/fuel info. My ignition includes a new msd 6-al box with a 6500 rev limiting chip. The distributor is a Ford, Duraspark? The coil is an Accel Super Stock #8140C, a typical looking cylindrical unit. The coil is seven years old with about 18,000 miles on it. The distributor was in the car when I bought it in 1997, I've put about 30,000 miles on the car and distributor. The guys at the dyno shop set the timing to 34 degrees total, I noticed they plugged my vacuum advance, it is still plugged. I have all new fuel lines and filter. I have a new mechanical fuel pump that is supposed to be good for 120 gph. It is an Allstar brand #40263. The dyno guys watched my fuel pressure gauge during the pull and they said pressure never dropped below 6 psi. I have a Holley 750 double pumper with mechanical secondaries. I believe it is a 4150/4779. It was set up by Jet Performance for my new engine. I am using a 3.5" tall round K+N part #E-1540 air filter. The air filter was in place during the dyno test. The headers appear to have 1-7/8 inch primary tubes with 2-1/4 O.D. exhaust pipes running into four glass packs. The heads were not ported, but Russ did a multi angle valve job on them. I haven't found the specs for the Isky or the Comp Cams springs. I guess I should ask Russ why he chose to go with the Iskys. I hope you are wrong about the cam, (that intake sure would be a lot easier to change), but you seem to be very knowledgeable about this stuff.
Thank you very much for your help,
Art
quote:Originally posted by george pence:
Art,
the dyno is the best place to diagnose a problem. I have more questions than answers at this point.
First, my random observations. Your motor is making about 407 bhp at the flywheel, which is about all you're going to make using the cast iron 4V heads without porting & a good valve job (multi angle). Although the cam is rated for power out to 6000 rpm by Comp Cams, thats with a 351 cubic inch motor, the extra displacement of your stroker moves the power band lower in rpm, I would have guessed power to 5750 rpm, but 5650 is close enough. David Berman had his motor dyno tested with an Edelbrock Performer adapted to work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at around 6000 rpm, feeding a 408 cubic inches. I never liked the Performer myself, but David's dyno results has given me a new found appreciation of that intake, you can make more power at the upper rpm with other intakes for sure, but I do not believe the intake is what is "choking" your motor. It may very well be the characteristics of that cam to drop off like a brick above the powerband, rather than the torque curve tapering downward at a slower rate, which is why sports car guys normally want a wide flat torque curve, rather than an upward tilted one. The upward tilted ones drop off faster beyond peak torque. When all is said and done, you may very well need a custom ground cam to get the characterisitcs you want.
Having written all that, I myself would not be satisfied with the performance of your motor either. I would expect it to perform better too.
OK, here's my questions:
Do you have assurance that the person who built your short block did a good job with the rings as far as getting them to seal well in the cylinders?
Did the dyno operators run any air/fuel ratio numbers while your motor was on their dyno? If so, what were the numbers like between 4000 & 6000 rpm?
What components is your ignition composed of, and how old are they?
What is your ignition timing specs?
What parts are your fuel delivery system composed of & how old are they?
What make & size is your carburetor?
What are you using for an air filter and was it installed during dyno testing?
What size are the exhaust pipes of the mind train system, and what type mufflers does it use?
Have your heads been ported and had a multi angle valve job?
How do the specs of the Isky 8005A springs compare to the springs recommended by Comp Cams?
your friend on the DTBB