94transbird

Are coatings allowed? If so coating your piston tops would greatly help that detonation problem and allow you to unshroud the valves. Why spend your money on a new crank and destroke it when you could put that money to something you could get more power from? Or is this mainly for the per cube aspect of it?

Also Andy Dunn wrote a little thing on the EMC, http://racingarticles.com/article_racing-72.html
Its pretty neat

Old SStroker

FWIW, The "destroked" crank comes free with the 4.8L truck engine.

Andy Dunn makes some good points. Heads are Job 1, both in selection of the casting and modificatons they receive. The OP has good castings, 243 cathedral ports. Getting them correctly ported for this application would be most important and where the money shouLd go.

11.5:1 max with VP100 unleaded race fuel should not be a big detonation concern with 243 heads. I'm glad that they decided to use a decent fuel.

Intake manifold selection should, IMO, move up to the "top three" for street EMC competition.

My $.02

Jon

hornerhotrods

iTrader: (2)

Well considering that the 4.8 crankshaft is a 3.32'' stroke and every other ls power plant has a 3.622'' stroke, you can de-stroke a 6.0 cheap using stock 4.8 crank. Unless you wanted some off the wall stroke crank there would be no need to purchase an aftermarket crankshaft.

I will have to agree with old ss stroker on the l92 heads. If your goal is a high revving small displacement engine than the l92's would flow enough air into and out of the cylinder as quickly as possible in the upper rpm range for minimal cash. Granted this may not score many points in EMC but the volumetric efficiency at upper rpm would be better than a smaller/ more restrictive cylinder head on the same motor.

Another thought is to figure out what the counter weights are setup for on the 4.8 crank to determine if you need to rebalance for the larger piston/rod combo. You could possibly profile or knife edge the crank if the combo allowed you to. Just $.02

94transbird

Ignorant move on my part. My bad.

Also is there a limit on compression? Or can you run as high as you want with the VP100 gas?

hornerhotrods

iTrader: (2)

Apparently it seems there is a cap on the street class to 11.5:1. Havent checked to know 110% for sure but thats what was stated earlier in the thread

94transbird

Ok. That would make sense. I have seen this advertised and covered in Hot Rod and Popular Hot Rodding and it is a great competition.

To the OP do it! I would love to do it... But funds and time are a couple of huge constraints at this point.

A.R. Shale Targa

iTrader: (2)

What about a near square stroked 5.3 ????
3.78 honed...small bore=fast flame=less detonation w/high cylinder pressure
3.76 crank....offset ground .140....compensate for shorter 6" small journal rod
replacement sbc scat rod= to new bolts and resize on pdrd metal stock rods
338 cubic inches easily fed by massaged 243s,possibly even epoxy runner
floors to reduce volume and strengthen port speed=important in this type
of dyno challenge 2500-6500 average power
definitely the truck intake and w/stock rockers and beehives w/tit retainers
you could custom cam it small perhaps 222-226 range...again to maximize
cylinder pressure @ low engine speeds
other than a few hundred bucks and a reputable machine shop to grind and
balance the crankshaft this combo would use cheap rods, the stock pistons
(flat w/no relief=efficient flame propagation) and minimal engine block
machining(hone)....just throwin' it out there

Old SStroker

Hmmm...

There is considerable evidence that says 243s like bores 3.90 and up.

As I mentioned way back in this thread, the exact opposite approach for a ~340 cube EMC engine makes sense to some but not to others: 4.06 bore, 3.268 (4.8L) stroke and L92 heads. This is not the "velocity makes toque/power" approach, but then again neither are all of the GM L92 headed truck engines. Ever driven a 5000 lb.+ GM 2500 with an L92 headed engine? How'd the low-mid range feel with pedal to the metal?

Conventional "wisdom" says that can't work. Guess nobody told those engines.

Just throwin' more out there...


Jon

A.R. Shale Targa

iTrader: (2)

Don't get me wrong I'm a huge fan of big bore(unshroud 2.16 in valves)
and short stroke(less piston speed-ring friction) but I remember the first EMC
challenge where Beck Racing Engines bored a 307 block .060=3.9375
and used a 3.75 stroker crank....somewhat unconventional but I think he
finished in the top 5 and had a flat torque band 365" on pump gas
I also see some posts of people having 04-05 SUVs w/5.3 and one head is
a 243 and one a 799 on the same engine from GM. wierd ??????
I also marvel @ how GM strayed away from the cathedral port and back to
a huge rectangle (265cc). I have to think that with the floor raised and the
4.065 bore along w/376 inches it obviously makes hay

94transbird

There was an article recently in popular hot rodding that had a small bore and long stroke gen 3 hemi making 700 hp. So it is obviously a great idea just exactly how you execute it.

hornerhotrods

iTrader: (2)

That doesnt seem very budget friendly but considering what you would have in custom pistons, balancing, valvetrain and other supporting parts that wouldnt be cheap either.