442scotty

I am just piecing together stuff to transplant a (2005) LM7 truck 5.3 into my 1965 Cutlass with a 200R4 trans. My car is currently running a Holley Terminator FI throttle body setup and Im trying to decide if I should put the throttle body on my 5.3 or use the stock multiport setup but from a LS engine.

Most important for me is getting as much gas mileage as possible.

I would appreciate any comments from those who have come before me

1964SS

iTrader: (1)

If gas mileage is #1 concern then multiport is the way to go. A wet intake throttle body system will not do as well as the LS fuel injection system on mileage.

442scotty

Darn... I was hoping you wouldn't say that lol

Brian Hoss

If its fuel economy you're looking for, you'll find way more bang in dropping that 4 speed for a 6 speed. The amount of fuel economy difference between those two injection units are minimal at best.

442scotty

A 4L80E ? Sounds like an idea... Anything beats the lousy mileage my 455 gives me

442scotty

I mean the 6L80

Brian Hoss

That's where I'd go. Can run the MSD trans controller for it. Keep your TBI unit and cruise on down the road.

1964SS

iTrader: (1)

The only problem with the 6L80 is that it's enormous compared to your 200R. You will more then likely have to do some serious massaging of your trans tunnel and have your driveline shortened.

1981TA

iTrader: (7)

I will be going with a tbi system on mine to preserve the carb look and because switching over to mpfi is costly in terms of time and parts for me.

442scotty

Bit the bullet and ordered the new Holley 300-130 dual plane intake. Onward!!!

zamora7

iTrader: (4)

Damn was hoping I would see a holley tbi for sale from you soon lol

442scotty

Sure thought about it