Engine rebuild for towing.

[mysticdragon72]

Got an 85 C20 Scottsdale that has the stock 350 5.7 and th400 tranny.  Want to use the truck for towing my horse trailer and need suggestions on what kind of mods to do to get better torque?  I'd like to use the stock heads but am planning on getting headers, new carb and intake as well as boring the cylinders 0.030 over stock.  Also planning on a mild rv cam but not sure which one yet, depends on the intake and carb.  What would you do to build a towing motor keeping the stock heads and keeping in a beer budget?  The stock rear is supposed to be 4.10 according to the book I got.

[rich weyand]

With stock heads, about the most torque you can get is with the Comp Cams 12-300-4.  That's what I'm running.

[mysticdragon72]

The motor has never been rebuilt as far as I know... It was used as a farm truck before we bought it and we've never done anything other than regular maintenance.  We bought the truck back in 04 and it had 85k on the odometer but with it being 5 digit who knows how many times it turned over before we got it!  It's now reading 45k so there's at a minimum 145k on the drivetrain... We're having the tranny rebuilt as well and we'd like to keep the engine rebuild cost below $1500 if possible.  I don't think we can get heads and everything else we want for that price from what I've seen.

[roundhouse]

I'd spend a little more and get a crate engine with the vortec heads and roller cam
Cost about $2200 for a that engine

I'd bet you have a flat lobe  on the cam
Every old 350 I've ever seen had a wiped lobe on the cam.  Usually the back cylinder on the drivers side

Easy way to tell is take the air filter off and go for a drive and start off from sitting still and wind the engine up to a high RPM and when it gets wound up good it will start making a popping sound

Or you could pull the drivers valve cover off and crank it over and watch the rocker arms to see if there's one that doesn't move as high as the rest


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