A mild street/strip 383 with LE LT1 heads and Ai
Golen 4-bolt mains and new Compstar crankshaft, SCAT 6" Pro-Mod style
rods with 7/16" rod bolts and Mahle -16cc D-dish pistons.
Clean up the block and installed cam bearings.
Lance had one spun rod bearing. The block is in good shape
and the pistons had a good ring seal. No need to take the
block to the machine shop. I'll just clean it up and put
some good parts in.
Ai sent a nice billet core camshaft that has mild lobes that
should be easy on the valve-train.
Brand new Compstar crankshaft. I had a local machine shop
balance it to a set of SCAT rods and Mahle pistons.
Just a photo of the cast-in CompStar logo. I measured for
main bearing clearance and had to go with .001"/standard mix
of Clevite P-series. Main bearing clearance ended up at
.002, .0025, .0025, .0025, .0025" from #1 to #5
64ft-lb for these 7/16" x 1.400" ARP 8740 cap screw
style rod bolts. Stretch is .005" but I noticed the
gauge moved when I took this photo. Rod bearing clearance is at
.0025" with Clevite H-series standard bearings.
This is a good connecting rod for a little over $300 bucks.
It's the SCAT I-beam (6") with beefy 7/16" rod bolts.
I wanted to get a rod and piston set made up and test to see if
the rods clear the block. This style of rod could bump the
bottom of the cylinder bore on the cam side. I
pre-clearanced that area of the block and hope it was enough. (yes
Rings are gapped for street/strip no nitrous. (.022" top and
Here is a good photo of the ring gaps. The piston in is the
one I assembled for checking rod to block clearance.
After gapping the rings the rod/piston combos are next.
Gerry Charlesworth F-1 wire lock tool put to good use here.
This tool allows you to neatly/firmly install the wire-lock
I take the rings out of the cylinder hole and install onto the
piston for that hole. Here is a close-up of the Mahle ring
package. 1.5/1.5/3.0mm rings and no oil ring support rail
since the piston pin does not intrude into the oil rings.
Torquing the SCAT 7/16" rod bolts to 64ft-lb and using a .018
or .020" feeler gauge as a shim. (hint, hint: rod
side-clearance is .018 to .020")
Bottom end assembled.
Big block Chevy oil pump and stock LT1 windage tray.
Degree check of cam and timing set. The camshaft is spec'ed
out from Ai and the intake centerline is supposed to be at 106
deg. The GMPP extreme timing set gives 109/110 ICL (due to a
very loose chain). I tried a new stock LT1 timing set and
the chain was even looser on that set and the cam was 110 deg
ICL. Then finally a Cloyes double roller was installed at +4
deg and that gave a dang near perfect 105.5 deg ICL.
Oil pan on. Needs paint touch-up.
The one in-focus photo I have of the pistons. This is just
prior to putting on the FelPro 1074 head gaskets. The
pistons are at 0.000" deck height and so piston to head
clearance will be .039"
My camera has not been focusing very well. I took a few more
photos of the heads but this is about it for clear focus.
Right now it's time to get the valvetrain on and then spin the oil
pump and see if oil gets to all the rockers.
Spinning the oil pump can bring to light minor problems. The
oil pump sounded and felt funny. Sounded like gears
grinding. Good pressure but I need to get a different
pump. Also, one lifter was bad. It was allowing too
much oil to pass up the pushrod and I was getting a geyser.
Swapped the lifter out with another used lifter and actually found
3psi more oil pressure.
I put this M155 pump on with welded pickup and put in a pink
relief spring snatched from another pump that was longer and felt
stiffer. This pump is standard volume. Spinning at
2500rpm it made 55psig.
I did put the stock windage tray back on but I don't have a photo
showing. Another thing (mistake) that caused a few hours of
rework was that I forgot to put the oil galley plug in under the
rear main cap. That plug divides the inlet and outlet of the
oil filter. No plug and the filter is bypassed and in theory
oil pressure would go up. I actually tested that
today. Without plug I had 65 psig with the M99HVS oil pump
at 2500 drill rpm. With plug I had 60 psig.
One last photo. This shows the used ATI damper (Y-body).
October 13th, 2008: Nabil Guffey has
the motor and will install it into Lance's '96 Impala SS.
Hope to see some low 12's in the 1/4 and smooth street operation.
Arriving at Mechanicsville EFI Performance
Lance is already here to pick up his car and Nab Guffey is giving
a good pose.
Snuffey Guffey gives the rockers one last tune.
Adjusting with the motor running and with a cardboard oil drip
Now the other side. Lance has the LT4 (Y-body) ATI damper
and so his accessories are spaced out 16mm. The passenger
side valve covers come off without moving the alternator.