djm2475

I recently installed a gm service crate engine into a friends 1969 chevelle....LS series 5.7 part #89017653(ls6 crate engine) ported and milled heads,lm7 truck intake,30lbs injectors, truck harness and ecm....my problem.... he had a shop dyno tune the engine and they said it made 248hp at the rear wheels?????? this is a 405 hp crate motor... they are blaming my intake for the loss of power. I under stand drivetrain loss but 157hp....please help????

94LT1Bird

iTrader: (4)

mustang dyno?

nixls1

yes it was a mustang dyno

riach

the truck intake would not effect you that much. when you drove the car how did it feel? you sould definately be over 300rwhp.

hellbents10

iTrader: (10)

Should make a solid 300+ to the tires, a LS6 intake would only be worth another 25 or so.

Frost

iTrader: (45)

more info too though...

ported heads on a stock cammed (ls6 cam) motor? There were a number of different LS6 cams, what year is this one? What kind of trans? If it's a th350 or 400 with a loose stall, then those numbers are pretty much on-point for a setup like that on a Mustang dyno. The fancy head money would make more HP if used for intake and cam.

Haans249

iTrader: (24)

All that is said above is true. If you're running a TH350-400 trans, heavy rear, and the truck intake, plus the mustang dyno all add up to some good low dyno numbers. Doesn't necessarily mean its slow! How does it feel when driven? Is there any abnormal sounds from the motor? Any access to the tune to post up? There are many things in a tune that can kill power as well.

Best,
Adrian

djm2475

You guy have all been great. Here is some more info, 4l60 trans 2500 stall converter, 4.11 gear.... Now they said the ecm is junk(not responding to anything or starting) this shop has a good repor....In a article i read a while ago car craft tested all the intakes the truck intake did quite well just a few numbers under the ls6 intake. if i change this will it make that much of a difference? what should i do? all help would be great....

Frost

iTrader: (45)

if the converter wasn't locked during the pull it will read lower as well

Swap intakes and see that the converter is locked in the retune if your guy is looking for dyno numbers. Get him on the track and see what he traps, that's the bottom line.