[Ace23]

Originally Posted by DAVID GAGNARD

I'll take a shot at it......

First off I don't think your cold cranking compression numbers are all that bad, cams with a lot of overlap and duration will not show high cranking numbers..and being they are all close together is another good sign.....

A 427 stroker built to making the advertised HP as yours was built to do will have an aggressive cam and will not like to run at low rpms like yours,it will come on in the higher rpm range as yours does......it's the nature of the beast......

Your fuel mileage will depend a lot on how your drive the car,if your easy on the gas pedal you should get better than 9-10 mpg,but if your like most of use and like to get on it and run it up to 4000 to 5000+ rpms shifting,well, 9-10 mpg is all you can expect......

Your low rwhp #'s could also be tied in with your exhaust...I'm not familiar with the type you have,but it has been proven time and time again on here that exhaust/mufflers plays a big role in rwhp, some have reported a proven 100hp loss with certain types of headers/mufflers....
taking off the side pipes/mufflers and running a pull or two without them might tell you a story you will not believe.....

one or two rear wheel dyno pulls is not enough to tune a car,don't know how many pulls you made or what was done,but at least a half day on a rear wheel dyno will get you the most out of your engine....
each engine I have had on a dyno (engine dyno) was the better part of a day..the tuner tried different jettings and different timing settings and overall at least 20 to 30 hp was gained by trying different configurations.....on my last engine,a change of 2 degrees in the timing was good for 12 hp....we went up/down the timing range from 26 total degrees to 34 total at 2 degree increments and there was a 24 hp difference from 30 to 34 degrees....something you would not know unless it was on a dyno...

There are other things besides jetting and timing to take in consideration,air/fuel ratio,volumetric efficiency and a number of other readings to get the most out of what you have......

Unless you go with a "modern" type engine,you will not have a smooth idling,banshee off idle engine, push rod,carbed, stroker motors just don't do that and make 585hp....

You do have a loss of hp somewhere and I think if you can get it figured out and up to where it should be, you'll be more than satisfied with your engine......

good luck with it and keep us posted......

david

David
Thanks for your input. When the car was tuned the tuner did exaclty as you described......I would say a good 3-4 hours was spent tweaking the carb and making timing adjustments while on the dyno. I guess I have overlooked the exhaust. I called Firefly and they told me the pipes that were purchased for my car should be 2.5". I guess the only way to tell would be to remove and measure to verify. As you have mentioned there are quite a few stories about the HP gained from removing or swapping exhaust. While I have no reason to doubt the Firefly exhaust is better than the stock exhaust I should still investigate this as a possible issue. Its pretty weird how well the car runs to be down on power. Will keep everyone informed if anything is found that relates to the exhaust. Might need to check the headers and how they mount up to the heads as well. The headers were custom made 2" to fit the Brodix heads back in 2004