Hidden in the shadows of NASCAR lies the oldest automobile
racing sanctioning body in the United States known as IMCA.
IMCA is based on enforcing fair and consistent rules that
promote affordability as the foundation of racing in America.
Through the promotion of the "grass roots" weekly
racer, IMCA has seen remarkable growth since the late 70's
in what are mostly 1/4 mile to 3/8 mile dirt or clay circle
track venues in small towns across the nation. Click
here for tracks.
While founded in 1915, it wasn't until previous IMCA owner
Keith Knack introduced the Modified Division did IMCA really
take off throughout the United States. Keith Knack has since
sold IMCA to Kathy Root who has championed Knack's vision
to make circle track racing relatively inexpensive and competitive
from coast to coast. IMCA Modifieds are known as the "calling
card" of IMCA.
IMCA Modifieds have become the calling card of IMCA, thrilling
legions of new local dirt circle track fans every year
from coast to coast.
Key IMCA Modified Rules
or newer OEM perimeter American rear-wheel drive passenger
car frame only.
Minimum wheelbase 108 inches, maximum 112 inches, both
sides. No part of frame can be lower than four inches
from ground except front crossmember.
No composite body panels allowed. Body must be same
width, front to rear, and parallel to OEM frame.
All front suspension components must be steel, unaltered
OEM, in OEM location, and replaceable by OEM parts,
with some exceptions.
No rack and pinion steering. All components must be
steel, unaltered OEM, and in OEM location with some
No independent rear suspension. All components must
Must use unaltered Hoosier Race tire, G60-15 (8.75"
width) with IMCA stamped on sidewall.
Complete Rule Book
their popularity due to a carefully crafted set of rules that
lower the barriers of entry found in the IMCA "Late Model"
Division or any other competitive circle track division for
that matter. Along with having to run a '64 or newer domestic
passanger car frame and the 8.75" wide tire limit, the
engine "claimer" rule helps keep a level playing
field in terms of costs and horsepower.
Realizing that racers at this level have a wide range of budgets,
and that this can make for lopsided races, IMCA utilizes an
"engine claim rule." Roughly put, the top four finishers
at any event are subject to an "engine claim" by
any racer from 5th place back. What this means is, if you
sink $5000 or $15,000 into your block, rotating asembly, heads,
valvetrain, and intake (carb, headers, distributor etc. not
included in a claim) then your competition can claim your
motor for a mere $550, or exchange for his engine. It's a
great rule in spirit, but unfortunately rarely does it play
out as written because the winner can decline to honor the
claim and simply put up with a three race suspension.
What is particulary fun regarding the engine requirements
or lack of in the IMCA Modified Division is there is very
little in the way of limitations as to what parts you can
or cannot use to make up your motor. However, on any night
you could be claimed. That means the challenge is to build
as much horsepower as possible and as cheaply as possible.
And for an enterprising engine builder, this can be a lot
of fun. The key is to understand which components in the engine
will give you the greatest bang for your buck and which components
you should save a few bucks on.
IMCA Modified Engine rules are as follows. Take note there
is no displacement limit, this means even big blocks and or
strokers are permitted. Also, keep in mind that running a
Ford can work in your favor since 95% of IMCA Modified cars
are bow-tie powered... this means 95% of your competition
wouldn't want to run your motor, even if their claim was honered
by IMCA officials. This gives the Ford IMCA Modified racer
a bit more comfort in extra engine development and investment.
"Any American make steel engine
block allowed. Aftermarket and OEM performance blocks allowed.
Steel heads and oil pan only. Flat tappet cam/lifters and
stud-mounted rocker arms only. No stud girdles. No mushroom
lifters, lifter diameter and configuration must match OEM
passenger block. OEM firing order cannot be changed. No crank
triggers. All engines must be able to be used in conventional
passenger car without alterations. Engine mounts cannot be
removed or altered. Castings and fittings must not be changed.
No machine work on outside of engine. All belt driven accessories
must be on front of engine. Wet sump oiling system
only. External oil pumps go with engine if claimed."
Tmeyer Inc. Small Block Ford 454 Build
As you probably surmised, due to the intensely competitive
nature of the modified class, engine builds are a closely
guarded secret. Not many racers (at least the winning ones
anyway) are willing to reveal what goes into their powerplants.
Recently Tim Meyer of TMeyer
Inc. allowed us to get a rare look at 351W based 454 stroker
that he was building for a client. This particular racer has
always run 351W based 396 cid strokers in his race car, and
this season wanted to up the displacement to 454cid. This
engine will be used in this seasons IMCA Modified series -
however, not revealed to us was the drivers name, car number
or anything else that would allow someone to identify where
the engine you see below is going to be run!
This build starts with a new TMeyer Cast Iron 351W block.
The blocks are offered with either a 4.000" or 4.125"
bore sizing, the latter was selected for this build. The
blocks come ready for finish machining. Tim Meyer finish
hones the bores and mains, surface mills the deck, and
runs a hone through the lifter bores.
The H-beam rod assembly comes TMeyer. The 6.250"
rod is 4340 forged steel and comes with ARP 8740 cap screws.