69chvl468

Im putting a 5.3 and 4L60 in a 71 chevy truck. Just wanted to know some details and what kind of problems anybody has had, like clearance issues, tranny Xmember, AC box, motor mounts etc.. any help would be great.

ls1nova71

iTrader: (4)

You can check out my build thread, it's a 6.0 but basically the same. I built a 68 with a 5.3 a couple of years ago, but I do't have a build thread on it.https://ls1tech.com/forums/conversio...6-0-4l80e.html

69chvl468

Thanks, what did you do for a tranny mount??

ls1nova71

iTrader: (4)

I used the factory automatic transmission crossmember, just slid it back and drilled new holes in the frame. Unless you take the cab off, or are real good with an angle drill, you won't be able to use the upper frame bolts, but it's never been a problem.

Also, I used the 72 rubber mount so the holes in the crossmember would work.

69chvl468

Thanks for the info! A friend of a friend is paying me to convert his truck over to a 5.3. You have helped me in the past with a couple issues with the LS1 swap in my 69 chevelle. Check out my pics! Also I like what you did the motor mounts. Did you use the late model truck mount and frame bracket? Just trying to save some $ not having to buy mounting plates. Thanks!!

ls1nova71

iTrader: (4)

Yes that's what I did, I took the frame stands off of the 2003 truck (they unbolt) and fabbed some pieces to them so that they would bolt to my frame. Not having to use the '72 frame stands also allows the F-body exhaust manifolds to be used without hacking a piece out of the frame stand. But I did still have to notch the frame a little.