Considerations for a truck pull engine?

[randy331]

What class, weight, final drive ratio, manual or automatic ?

I'm currently building a new engine for my son's pulling truck.

Dart shp pro block, callies magnum crank, callies ultra rods, custom JE pistons.

My opinion is with those saying good stuff and ability to over rev and the truck set up being just as important as the engine.
Sled speed wins the show.

They are endurance engines but not like dirt track engines.

Randy

[user-29956]

I'm looking specifically at NA big block stuff in the 500-540 cid range with conventional style heads, cast manifold, single dominator, wet sump, solid roller etc. 16-20 seconds worth of pulling with tire spin and a steadily increasing load. Lots of mass to get moving at the beginning, lots of load on the engine, and a sustained rpm for the majority of the pull.

A good cam and valvetrain guy will be extremely beneficial for your cause. I have done alot of testing on BBC's in that cubic inch range, and when talking the rpm's necessary to be competitive in that arena.....valvetrain becomes very critical.!!!!

[englertracing]

Do people use heavy cranks and flywheels in these classes?

Also, why the Chevy and not a bbf?

[EngineTech1]

Do people use heavy cranks and flywheels in these classes?

Also, why the Chevy and not a bbf?

I don't know what most people do but considering that these engines are pulling pretty much steady state and not shifting gears then the idea of a light weight crank seems less beneficial especially if there is any kind of trade off in rigidity or strength of the rear flange where the flywheel bolts up.

Chevy just happens to be what my friend runs and someone was asking specifically about the brand. If I was building one for myself I'd likely go with a ford.

[englertracing]

I was thinking that it might be beneficial to go with a heavy crank and then test various flywheel weights, the power and torque are still thete but the transition from hooked to wheel spin will be less abrupt and more controllable,
A 500 Jawa speedway engine uses a 24lb crankshaft, makes the bikes rideable. Where a motocross 450 crankshaft is less than half that weight.