Hi Steve,
Something is definitely missing in that equation. If only the duration
is
increased, why would you need to port the block? Same holds for the stronger
springs. If the lift is the same over a longer duration, the valves would
probably open and close slower than stock for a given RPM. Sure it's not
necessary to put headers on, but I don't think a cast exhaust manifold can
breath as well. Isky reground my BJ8 cam to a slightly longer duration and
higher lift, the base circle of the lobe is almost flush with the shaft now.
Best,
Greg
-----Original Message-----
Hiall,
Saturday I heard from someone who should know (Kurt Tanner) that a Mk 1 3000
cam in good shape can be ground to 290 degrees with all other specs per
stock and that that, in combination with strong valve springs (and relieving
the block) will "transform" a Mk 1 to BJ8 plus performance while keeping the
stock 1-3/4" carbs. He said it's not necessary to add steel tube headers but
using a Monza exhaust adds horsepower as well. He showed us one--all the
pipes are larger--I didn't measure it but the tailpipe looks like 1-3/4 or
2" and one could improve on the wussified sound of the Monza by welding
straight pipes on the end in place of the muffled tips. Tanner says the
Monza fits through the roadster frame cutouts as well.
He said using the smaller carbs with these cams works better than the 2
inchers because they'll "almost" idle due to better velocity than the large
pots.
He has some old unused race engines he's acquired with these cams and
believes they were originally either reground by Isky or Sig Erson. He has
installed one of these cams in a roadster purchased by a knowledgeable
customer who, he said, was amazed at the power and said it was the fastest
Healey he'd driven.
I notice Denis Welch's hot street cam is 278 degrees--Tanner said the BJ8
cam is 265 degrees.
Discuss.
--
Steve Gerow
Pasadena CA
59 BN6
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