tbo07

I am more of a jeep guy so this is all new to me, here goes.

My engine builder and the guy who has my car are both telling me two different things. So I want to know what you guys think.

To start this is my motor.





MMR 4.6 Street Mod 900 (up to 900HP)
*Brand New Cast Iron 2004 Cobra Block, torque plate bored and honed
*New 4340 Forged 3.543 stroke Cobra Crankshaft w/micro polished journals at no extra charge
*New 4340 5.933 Manley H-beam Rods w/ARP rod bolts ( These US made rods are shotpeened, magnafluxed and weight matched to bring you the finest H-beam rod available for your 4.6
*New Forged Manley pistons 3.552 Bore size (High or low compression)
*Speed Pro file fit rings (precision file fit to your application, nitrous, blower, turbo or N/A)
*Speed Pro/Federal Mogul tri-metal Rod and Main bearings
*Complete Pro Assembly and Balancing for the smoothest, highest revving shortblock available.

Shortblock Options:
Coated Pistons (ceramic dome/teflon skirt) $399.99
Brand New Current production Aluminum Block +$699.99 for NA or $729 S/C Blocks
ARP 2000 Rod Bolt Upgrade (recommended for 900+HP) $99.99
ARP Mainstuds (recommended for 600+HP) +169.99
MMR Street/Racing Oil Pump (highly recommended) + $199.99
ARP Headstuds and MMR/Felpro Extreme Duty Headgaskets + $369.99
MMR windage tray and hardware kit (+15HP) + 129.99
*Due to the custom nature of MMR shortblocks ALL customers paying with a credit card
will be billed when the order is placed (prior to engine assembly and shipping),
All MMR shortblocks are non-refundable regardless if the item has shipped or not.

400900
$2799

I have sent my heads and timeing stuff to mmr. They are going to do a stage 2 port and polish. Install new valves and 5 angle valve job.
The car is tubro charged. O.K. here is the rub.
The turner says I should let him break in the motor on the dyno. And if it does not make the same power as the stock motor I should have him yank it and send it back.
The builder {mmr} says the worst thing I could do is let them break it in on the dyno. I should run the car for 500 miles with the tune that is already in it. Keep it out of boost. Then change the oil. Then dyno it. mmr " the hardest thing you can do to a motor is dyno it"
What do you guys think?
Thanks in advance
Tim

IROLLSALEEN

run a wide band, andd break it in in your car OFF the boost

tbo07

Man I hate to sound dumb, but
What is a wide band[:-]

2000GT4.6

Never ever break it in hard.

Do what the manufacturer says.

A wideband is a 02 sensor/display that tells you the a/f ratio of the car. You don't really need one if you stay out of the boost, as the dyno will have one.

IROLLSALEEN

I just ment for piece of mind , dont want to go lean ona new mill. And with boost in the future he is gonna need it anyway.jmo

tbo07

The car will have the turbo installed when I pick it up,
I am not sure if that was clear.

IROLLSALEEN

ya just stay out of it till its dialed.

tbo07

Thanks I have a lot to learn