Short Stroke BBC 477 Dyno Results - 2014 Engine Masters Challenge Motor

[uxojerry]

I wanted a big bore short stroke motor for my 68 Corvette Coupe L88 type pro-touring project. Eric Weingartner wanted to build a small cube BBC for the 2014 Engine Master Challenge. The best dyno run yielded 810hp at 7000rpm. The highest tq reading on any run was 666. My T56 Magnum and my irs ought to live at that tq level.


Components:

Dart Big M with a 3.75 x 4.5 bore and stroke.
Callies Magnum crank with SBC rods for a light weight rotating assembly.
The engine is using a piston guided rod set up
AFR 305 heads custom ported to 400+cfm at .600 lift
454R intake custom ported.

Eric spent countless hours working on this motor and I think both of us were surprised with the results. The engine yielded 806hp at 6500rpm which is the upper rpm limit for the competition. The EMC Challenge is next month. I have been mulling over a short stroke motor for a long time and was surprised at max hp arriving at 7000rpm versus 8000rpm. I was surprised that the engine had plenty of tq down low but not too much for a T56 and irs. Im now mulling over a short stroke big bore SBC build to see if it yields similar results.

Example:

My SBC 427 yields 565hp and 585tq.
The BBC 477 yields 810hp with only 666tq.

Both motors are straining the drivetrain at more or less the same. I have a set of AFR 245s yielding 350+cfm at .700 lift. Im thinking I could get 700hp with less tq than my current SBC. $$$ will postpone this experiment until next year.

[uxojerry]

Looks like the engine is in 3rd place, soon to move to 4th, lol. Throttle Performance built the most beautiful Pontiac motor Ive ever seen and it should take the win. It is under protest but hopefully gets resolved.

Current lead is an LS 435 with 723hp and 618tq, followed by a Ford Clevor 433 with 605hp and 583tq.

The 477 came in at 762hp and 634tq and is in second place for total horsepower.



If your a lawyer you will have fun reading the Engine Masters competition rules. Generally the scores are based on ave tq/hp from 3000-6500, added to peak hp and tq, then divided by the number of cubes. I think, lol.

Everyone should be happy that an LS motor smoked my bbc, lol.