Tom, Kelvin et al......... <~~~lawyer talk for youse guys
These are the mods I am doing on my 1622 +.040 MGA.
I prefer a different approach. My engine will look totally stock from the
outside, but inside........
I decided against the Xflow head because it really comes into it's own at high
rpms. You lose quite a bit of torque below 5000. You have to ask yourself how
often are you above 5k rpms? The breathing is very poor at low rpms. I decided
to go with a Peter Burgess modified head which will produce very near as much
power as a Xflow with MUCH more at low to midrange speeds. A little porting
and a 5 angle valve job. S-B inlet guides and hardened seats too. I plan on
using stock size valves, for better low end power, but switching to the
Rimflow design.
I am using roller rockers from Cambridge Motorsport for 2 reasons. One: the
stock ratio is about 1.42:1, I say "about" because every rocker will very a
little bit..... normal during production runs. and Two: the CM rollers have a
ratio of 1.625:1, higher lift, more fuel in/out= more power (with the right
cam). The rockers have less friction and a correct ratio ---- essential for
accurate cam timing.
I chose a Kent Cams 717 gring as giving me the best combination of torque and
power. Good torque comes in at about 2500and continues up til 5500. HP peaks
out at 5600. All in all a good range. The duration, off the top of my head, is
270.
For carbs I will stick with the stock 1 1/2 SUs, but modifying them to flow at
the 13/4 rate (about 200cfm or so I think). Easy to tune and I some around
too. Again the engine will look totally stock from the outside.
With the stock fan you will lose a few HP over the electric one but for me
it's stock again.
Stock cast iron exhaust manifold, unless someone can convince me, on a dyno,
that a header will help on my specification engine. I have a NOS Abarth system
that I'm putting on, a period modification.
ARP fasteners, Crane pushrods, usual work to the block, crank and rods. Piston
type and manufacture is not decided at this time. Cast pistons do not expand
as much as forged but forged are stronger. If thats an issue below 7000 rpm
is an unanswered question. Compression will be between 9 and 9.5:1.
Stock oil pump shoud do fine but will be checked against specs. Some of the
rebuilt ones are not within blueprinting specs.... easy to check and a cheap
fix anyway.
Just my thoughts
"Midget" Susan
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