Author Topic: 445 with Survival heads, hydraulic roller, Performer RPM  (Read 8457 times)


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445 with Survival heads, hydraulic roller, Performer RPM
« Reply #1 on: January 19, 2013, 05:47:13 AM »
Been flogging on the first engine that has run with the new heads - and we've got it pretty well sorted out now.  First impressions are very positive - with more certainly to come as we get additional experience with these and refine both the heads and the combination.

The "mule" as it were is a customer engine destined for a '68 Mustang in street/road race trim - a complete RRS suspension coupled to a tweaked C6 trans.  The 390 has the 4.250 stroker kit with +/-9.8:1 compression.  Pistons are a Survival specific forging from Mahle featuring skirt coating, a 1.5-1.5-3.0mm ring package, and round wire pin locks.  The rest of the combination is pretty much normal with a Moroso "T" road race pan, a Performer RPM intake, and topped off with a 780 vacuum secondary QFT carb.  Hydraulic roller camshaft is now "up" a step with 224/230 duration at .050 and .563/.563 lift.  T&D bolt on rockers.

Cylinder heads are the first iteration prototype castings that still had the recessed spark plug location - a machining error that was fixed before the initial production run.  These are the only two complete heads that were made like this - other prototypes were sliced up for cross sections and inspection.  As such, the timing requirement remains traditional, with best power between 36 and 38 degrees total.  I would expect this to be reduced to some extent in true production parts.

Heads are very, very much "as cast" - with only a basic 30-45-60 three angle valve job, and a blend from the valve job into the bowl.  Casting flash was removed from port entries and exits but no port work or reshaping at all.  For those of you who saw the heads at Columbus and/or PRI - these are the exact units that were on display.  Valve sizes are 2.200 and 1.680 with 11/32 stems.  The valve job will likely see some revision as we get things further refined.

The Performer RPM was port matched, with the rough shape handled by Willie on the Bridgeport and hand finished by Marc.  No break-through into pushrod openings, although it does get close on a few.  You could easily duplicate this effort at home with some patience and a die grinder.  We ran the engine with a one inch open carb spacer.

Engine break-in and sorting was pretty much a zero drama deal.  The only glitch was a interference problem with the Ford kickdown on the carb.  The adjuster screw was out quite a ways and would contact the secondary linkage on the carb - keeping the secondaries from opening at WOT.  Had me chasing my tail for a little while on fuel mixture.  Once corrected, we ended up within a jet of factory settings on both primary and secondary sides.

We were hoping to meet or exceed the power levels of the Stage X modified heads while running a smaller cam - targeting a street oriented package.  The results speak for themselves in the charts below with peak power at 495 and peak torque at 520.  I was originally going to run an even smaller cam - so the data is a bit "non-comparable" but I think the trends are clear enough to illustrate that the new heads are far stronger throughout the power band.  The bigger 234/240 cam Stage X combo sneaks ahead right at the end of the curve, but has had it's behind "handed to it" all the way up to peak.  The off the shelf Edelbrock headed package with the original smaller cam is not in the same zip code...

Pics, video link, and charts below: