Very interesting discussion, I'm learning alot. It sounds like an engine with enough power to push the truck into the 13's will be fairly tempermental on the street. I guess I have to make the decision to settle for less power but better drivability and reliability, but a slower truck, or build the other engine I had in mind for the truck.

The other engine would be (plug your ears!) an aluminum block 5.3 LSx destroked to 4.8 using a 4.8 crank and longer forged rods, forged pistons, ported heads and a cam/valvetrain to handle 8500 rpm. It would also get an IR intake and four Dellorto's. Even being a V8, it would be a pretty unique build and definitely not "cookie cutter" under the hood.

If you couldn't tell already, I like high revving engines- while my daily driver VW has a ton of low end torque and will climb any hill in fourth gear just barely touching the throttle, it only pulls to a little over 5000 rpm. With short gearing it just runs out of steam too quickly, and I don't want the truck to be the same way. The VW actually has too much low rpm throttle response- it can be hard to drive smoothly in first and second gear if you're not very smooth with the gas pedal, and again the truck doesn't need to be this way. I think a bigger cam that would shift the powerband up the rpm scale would actually help cure some of the low end snap or "touchiness" and be a bit easier to drive smoothly actually. A 3800 pound truck probably won't have that problem though.

Just throwing some thoughts out there so you guys can see where I'm at with an engine build for the truck. My sister has a Trailblazer SS that runs 14 flat, and I'd like it to run a bit quicker than it does. A friend has a WS6 Trans Am that runs high 12's, and honestly I don't need it to be that quick on the street. I don't need a ton of power on an autocross track, mainly would need a wide powerband since any shifting kills time. I would defintely rather stick with the 250 if it can be made to work, but the extra power an less weight of an aluminum block LS has it's appeal too, as much as I don't want a V8.


1966 Chevy C10 Driver/Pro Touring Build
http://67-72chevytrucks.com/vboard/showthread.php?t=474456