I'm headed over to Bob Lambeck's place on Thursday to dyno-tune the 496 after pulling it post Silver State Classic oil-starvation due to an incorrectly set adjustable bypass. I replaced all the bearings after I found some mild signs of starvation. I also found I had insufficient chamfer clearance and most of the bearingsd had a tiny ring of copper on the outside from rubbing the fat radius. New narrow bearings with hand-clearanced edges solved that problem.

Last time I had it dyno'd was when I built it in a mad rush to make it to MATS after killing the crank at March Meet. There was no time to tune, just a break in with a bad carb, then one pull with the replacement carb. We knew it was pig rich, but had to go with it for the sake of time. After pulling 8 jet sizes out it picked up over 3 tenths.

What do you think it will make now? I won't spoil your guesses with the old numbers unless requested.

440 +.040, stroked to 496 with a 440source 4.15 kit
10.44:1 compression, 91 octane pump gas
Holley 1000HP
MP M1 single plane intake
.597/.607 257°/259° @.050 sold flat tappet
Eddie RPM, unported, port machining transitions smoothed/gasket matched
2 1/8"/3.5" TTI headers
MP distributor, 35° total

ETA: Engine dyno, not chassis

570 hp....

562HP (engine dyno)

570...562...

WOW! I will be pretty impressed if that motor makes close to 700 hp at the crank!!!

I will guess 450 rwhp

522 hp

should have specified "engine dyno"

Ah, in that case I will guess 568

615 HP at 6100 to 6400 RPm and 640+ ft. lbs at or close to 4300 RPM The results depends on the local weather, dyno brand and settings on the engine dyno

'tis still the wee morning hours over here, and I'm loading the engine up to go. Any last guesses?

605Hp @ 5800
628Ft-Lbs @ 4300

645-ish

Good luck Dan

Dan...where's the results?

609.1 @ 5500
647.9 @ 4400

I'll post the average numbers in a few minutes, but it is a big, fat, flat power curve.

very nice!

Can I ask ball park the cost of running your engine on Lambecks
dyno?? I assume 3 pulls.

Cost: $550 for 9 hours and 21 pulls.


Correction: Final was 609.1 @ 5700 and 647.7 @ 4500
over 600 HP from 5200 - 5700
over 600 ft.lb. from 3700 - 5200

First run was 575/604, and every run we would change 1 thing.

On 91 octane, the engine made more power each time we took timing away. It runs best at 30° total, not the 36 I was previously running.

The carb ended up wanting 7 more sizes on the primary and one less on the secondary for a final of 84/88.

Swapping the HS air bleeds from 25 to 29 gave me about 5 on the top and got rid of a rich condition past 5000.

Adding a 1" 4 hole over a 1 inch open was worth 13 HP and 9 ft.lb. over no spacers at all.

My 14x3 paper air filter cost me 10HP over no cleaner at all, a 14x3 4 ply K&N only cost me 2HP.

There is a slight surge over 5500 that couldn't be tuned out since it is a result of not enough exhaust duration to compensate for my tiny ports. Only fixed by porting or a new cam.

Further pulls revealed the engine was still running well past 6600, but power was down to 552 out there.

I'll post copied of the dyno sheets in a little while.

Nice!!!

Saw it late but I was gonna guess 600/600....on paper it looked very close to my old 508 Stage V/Hyd roller combo that I figued to be in the ~620 range.

Guys looking for a 'default' 500" 600/600 combo need look no further File it inthe tech archives!!