I'm curious to see what some of you guys come up with for possible problems
with my motor.
It's 461 cid BBC with World Merlin heads, J&E pop-up pistons (11.5:1) and
Comp roller cam. The valve lift is .668 and .678. Timing is at 35 degrees
total advance through an Accel HEI distributor.
The motor is way down on power and will only pull my Pontiac Trans Am to
150mph in the mile. I can feel the power come on better at about 4800rpm when
the cam comes on, but still nowhere what it should be. I'm shifting at 6000.
There is a "popping" from the carburetor as it pulls. The warmer the motor
gets, the more frequent the popping. When the motor is stone cold, it will not
start until it throws at least one good fireball out of the carburetor. Once
the motor is warmed up, it starts really nice with no fireball.
I've changed the fuel cell, fuel lines (1/2"), fuel filter(1/2" passages
throughout) , fuel pump(Holley Blue) and carburetor (1000 cfm Holley). I've
changed the plugs and wires.
One observer suggested cam timing or a possible bad lobe (bad lobe not too
common on a roller cam). One observer suggested the cam might be off one full
tooth, but it was pointed out that with the valve lift on this cam, the pistons
and valves would probably let me know if I was off a full tooth. I'm thinking
(and hoping) that the valves are set too tight and aren't closing all the way.
(I haven't yet checked the clearance.)
This motor should probably put out 600 - 700 hp or more. It feels about like
350 - 375 when on the track.
Does anybody have any other ideas?
Dick J
In East Texas
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