BBC Horsepower limits?

So i think I finished the 2013 season right around 2000 hp using a Merlin block (not filled - no water) bbc. The question is really how far can you push a "standard" BBC, as opposed to AJ/TFX/Hemi style blocks. For 2014 we've got brand new GRP rods with L19 bolts, brand new JE Pistons, and a brand new Bryant billet crank. We're using high end bearings and Hell Fire rings.

So on top of this is a 14-71 Hi Helix Littlefield - but not LB20 style. We turned it at 30% over at the end of the year.

Any thoughts on how much OD I can run this blower and at how high an rpm on the engine? We were shifting at 8,000 last year and trapping at 8,400. I could go to a 3.90 gear from 4.10 to drop the rpms. Someone pointed out that rod bolts don't care about engine torque, they care about engine rpm. Of course the main caps in a BBC certainly care a lot about torque....


So the question is simple:

How much overdrive can I reasonably run?
How much RPM can I reasonably spin?

(what else do people need to know about the combo?)

 

The Chevy can do a lot up to 8500 or 9000 depending on the heads. If you bought good bottom end stuff the valvetrain will be the weakness. If it's an iron merlin with billet caps you are in good shape. even better if you bought a crank with hemi rod journals.
Bill Doucet is a member on here that builds a bunch of blown Chevys. He can point you in the right direction.

 

Depends on which Merlin block you have.

Blessings..........Ron C

 

Chevrolet on Nitro

We have run our Iron block Dart @ 9600 rpm, that was on a 6.12 @ 242 at this years Bowling Green NHRR. We only run 14% blower overdrive, but 97% Nitro.
Stephen McClain
Tri-State Racing AA/FD

 

We had a 526 BBC merlin block with big m heads, 14/71 littlefield hi helix, we ran 50 over, 6.20's at 226 at 8800 rpm.

 

Splayed billet caps. Merlin III 9.8 deck iron block.

 

That's good to hear. We went 6.28 this year at 30% over. Thinking of going up to 40% but didn't want to be completely stupid with the combo.

 

"So i think I finished the 2013 season right around 2000 hp using a Merlin block (not filled - no water) bbc. "

On a Merlin III, at 2000hp your already pushing it beyound a stable life. It's the least of the iron blocks and not really designed for where you want to go.

Blessings.............Ron

 

What other kind of Merlin Iron block exists?

 

The III is the only one currently being produced but they made two others in the past with the Merlin Pro being the best one. The Merlin Pro is still being used in some pretty high hp applications.

I know that's not what you wanted to hear. We run one (III) in my son's blown alcohol dragster at about the 1600hp area which runs a best of 6.57 @ 210.

Blessings.......Ron Clevenger

 

Unfortunately there isn't a simple answer as so many things can kill an engine.
The first things that come to mind are too much timing, not enough fuel throughout the entire rpm range, too big of bore, inside head studs, etc.

I had loose main caps that I chased for a while, come to find out it was an imbalance in my clutch, it certainly wasn't a block issue even though it looked that way.

I've heard of the Dart cast iron blocks up in the 2500 HP range.

 

Thanks for that. It's not about what I "want to hear." It's reality of others' experiences. Maybe I'll just upgrade to the same deck height New Century block next time so I can use most of my remaining components.

 

I run the "New Century" in mine. It's an exceptionally good block and value. Lowell is a pleasure to work with.

Blessings......Ron C

 

Ron, is your block done with a big cam tunnel and big lifter dia ?

 

No, for what I'm doing I just didn't want to go down the road of increasing the cost of cams and lifters. I do have .904 lifters. I run an external oil pump and Jesel front drive Dist so none of that runs off the cam.

Blessings.........Ron

 

Do you know how much power your combo makes ?

 

What make of oil pump? Any pictures of the drive setup?

 

Never had it on the dyno, past 6 years been running a gas blow thru carb deal with a F3-139 and it would run 6.20's & 220 mph (Outlaw Racing). Currently have switched over to alcohol with a Travis Quillen MFI and the F3-139. I'll start testing it this coming Sunday.

The external oil pump is a Moroso single stage. If the picture comes through you can probably see it in all that mess.

Blessings....,,.........Ron Clevenger

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