Street Machine Australia — January 2018

STAGE WRITE

MAIN: Bob loves a tough street-and-strip

tri-five, and 2017 Drag Challenge competitor

Daniel Grima’s N/A LS2-powered ’55 Bel Air

is a fine example. Running consistent 11.8s

all week, Daniel placed second in the K&N

Dial Your Own class

M

ERRY Christmas, readers, and

happy New Year.

Hats off to all the people who

participated in Hot Rod Drag Week

in the US and our own Street Machine Drag

Challenge here in Australia. What a fantastic

effort. It’s great to see real street cars that

get driven in the heat and through rain on real

roads and then go racing; they are putting the

‘street’ back into street machine!

Last issue I stated that if I was a millionaire

and could have any car I wanted, it would be

Sonny Leonard’s street-driven, 840hp 615ci

’57 Chevy. And looking back at the cars I’ve

owned, I loved my 396 big-block ’57 Chevy

A/MP-class drag car and 265-cube Blue

Flame six ’57 tow car. The popularity of tri-five

Chevs is growing, so here are some thoughts

on building one.

First of all, 11.0 seconds is the ANDRA cut-off

before a steel rollcage, side intrusion and taxi

bars have to be fitted. For a daily-driven street

vehicle, it makes sense to limit a car to run

11.0s or slower, especially if you want to carry

passengers in a two-door. If I was going to

build a sub-11-second, street-registered ’55-

’57 Chevy I’d choose a four-door body, as the

cab is structurally stronger and passengers

can still get in and out of the back even with a

’cage fitted.

Tri-five Chevys might look big and heavy, but

they are a lot lighter than they appear. My old

rat-powered shoebox only weighed 3200lb,

so a total weight of 3600lb for a comfy, air-

conditioned, power-steering cruiser is not

unreasonable. And it only takes 480 Moroso

horsepower to run 11.0@120mph at 3600lb.

To run flat 11s, an LS small-block is the

obvious choice, but there’s also nothing

wrong with an old-school, 23-degree small-

block under the bonnet. With the high-flowing

alloy or cast-iron heads available these days,

it’s very easy to make 480 Moroso horses

with a 23-degree-headed small-block Chevy.

I particularly like the Aussie-made Racer

Pro heads, and I’d probably build something

like a 383 stroker from a 010 four-bolt block

with 10.5:1-compression forged pistons

and a 3.75-inch crank, or buy a short 383

crate motor.

Another option is the 400ci small-block truck

motor. The humble 400 is often overlooked

in the performance world because of its

siamesed bores, cast-iron crank and two-

bolt mains, but they make wicked street/strip

engines. They’re like a poor man’s big-block in

a small-block package.

If I went the LS way, I’d go for a 427 LS crate

motor with a small 218-degree intake/224-

degree exhaust/110-degree LCA cam. It would

be super-reliable, good on fuel and lighter than

a big-block. I’d replace the factory EFI with

a single four-barrel manifold and throttlebody.

Fitted with a Moroso-type air filter, it would look

like a traditional carburetted engine, sound

good out the exhaust with the small hydraulic-

roller, and go very close to an 11.0.

Big-blocks in tri-five Chevs fit like they belong

there. There’s a smorgasbord of big-block

crate motors available that will push a mid-

50s shoebox into the 10s or quicker easily.

Power is only limited by how fat the wallet is.

But one of the issues when fitting a big-block

is the pipes. Despite ’55-’57 Chevs having a

much larger engine bay compared to many

BOB KOTMEL

TRI-FIVE CHEVYS MIGHT LOOK BIG AND HEAVY, BUT THEY ARE A LOT

LIGHTER THAN THEY APPEAR. IT ONLY TAKES 480 MOROSO HORSEPOWER

TO RUN 11.0@120MPH AT 3600LB