The dyno pulls identified two problems. One was a known.
The heads are on the small side. I built this engine on USAF Master Sargent pay supplemented by some Auto Zone part time money.
When I was getting parts for this engine, ford had discontinued the A heads. Would have been the head of choice, but I couldn’t wait around for one of the few at the time ford bracket racers to sell out. That left the C heads, $3000.00 bare, $1500.00 in porting, they are unfinished, there is no run them out the box. As well as $3000.00 for the Jessel shaft rocker system. $7500.00 was out of the budget.
The Blue Thunders out flowed the aluminum Cobra Jets I had, and would do so no matter what I did to the Cobra Jets.
So I bought the Blue Thunders. At this time it was also still fathomed that this would go on a stock block and I would drive it on the street. Target Hp was about 750hp.
Well with the head flow, and a medium cam we estimated exceeding the 750hp easily. So the big dollar bottom end parts were purchased.
The second area that the article does mention is these heads threw Ed. The flow numbers as I gave them to him off a superflow 6000 put them in line with some big chiefs. So the cam was designed similar to what that engine liked. Something about the port shape, the combustion chamber shape, something made this thing a torque animal and peak really early. It peaked on the dyno at 6600 RPM. BSFC was raising from 6700 on up. It only dropped about 100 hp all the way up to 7500 RPM.
All the dyno pulls started at 5300 RPM or so, so there never was a torque peak loaded. Projecting the curves back... Real scientific but it looks like torque peak is at about 3000 RPM, and is right about 900ft lbs.
Anyhow to shorten it up, the new cam is ordered, 325 advertised nearly 300 at .050 Some real steep ramps with some real square lobes. Should give me another 1000 RPM on the peak power and should put this little back yard project at 1000hp NA, even with the small heads.
As much as I would love Top Fuel numbers, Pro-stock cars are running 18-1 to 20-1 compression, have years of R&D, and LEASE for 3 times my investment costs, and make about 400 HP more than I will NA.
I’ve still got 500+hp of N2O to go, and if it don’t get me there quick enough, Ill add another stage. Nice thing about being a nobody… I only have to make myself happy.
Have to add an adendum to this, the prices above are actually for E heads. I didnt have an old catalogue available. C heads actually list for $750.00 a piece bare. Jessel rockers are still going to come in at about $1500.00 and your going to put a fair amount of money into tweaking those ports. So really figure about $4500.00 for a nice set of C heads.
<font size=-1>[ This Message was edited by: kim on 3/19/02 12:29pm ]</font>
<font size=-1>[ This Message was edited by: kim on 3/24/02 1:30pm ]</font>