Though far from spectacular, I wanted to share my dyno results for people to see what a typical, mild TPI 350 puts down. My motor is a .030 over 350 with forged flat top pistons, stock rods & crank, 461 Fuelie heads, 214/224 flat tappet cam, Heddman headers & y pipe and 3" exhaust. The top end has an accel TPI base, SLP siamesed runners, ported plenum and 52mm holley throttle body. Drivetrain consists of a T5 transmission and 10 bolt rear with 3.42 gears. The heads are obviously the restriction. I built the motor on a fairly tight budget back when I was in college a million years ago, and back then before we had the Internets, we relied on what locals proclaimed to be "the best heads", which got me a set of 461 boat anchors.

So, bad heads and all, the car put down 251hp at the wheels, and 331 torque at the wheels. Not really too bad all things considered. Assuming the standard 18% driveline loss, that puts me at just over 300 horsepower and 400ftlbs at the motor, which is consistent with my 13.8 @ 99mph ets.

He shut my first run down a little under 5k rpm, but the horsepower hadn't tailed off yet, so he pulled to about 5200 on the 2nd run. The 2nd run is what the printout represents, with a peak HP number of 249 horsepower, down 2 from my first run. You can see that the car built really good torque up until about 3900 rpm, after which it dropped off steadily.


Here are a couple vids of the run. The first vid was shot by my buddy from the rear of the car, and the 2nd was shot by another attendee from the front:
http://www.youtube.com/watch?v=Nzsw5BeVxLs&NR=1

http://www.youtube.com/watch?v=wcJMuoRT_Ms&NR=1

My main motivation for putting the car on the dyno was 2-fold. I wanted a baseline number for the sake of comparision. I'm building a 403 LSx for the car, and wanted to see the difference from before & after. I'm also taking this motor, putting different heads on it, and then putting it into my GTA, so it will also be great to see the difference that the new heads make.

 

Not to bad. Wonder how much more L98 heads would have made? I made 254whp with stock roller cam + 1.6 rockers on L98 heads with HSR intake up top. I would expect with abit bigger cam you'd make 15-20whp more.

The before and after with a 403 lsx isnt a fair comparison You'll likely make 251whp per bank with a built 403.

 

That's the plan. My goal is to double my RWHP numbers.

I can't wait to see what this same motor does in the GTA with vortec heads. It should really wake it up.

 

500whp is pretty easy with a 403 and definately a blast on the street. That will be fun

Vortec heads are great on milder motors. I can see a 20whp gain easily and maybe more.

 

Hopefully I'll see more than 20 hp from the vortecs. I think the 461s are REALLY holding this motor back. I suspect that they're very lazy at low RPM, since the only way they made power in the old days was with solid lifter cams and high RPM. A good set of vortec heads should boost my low and midrange torque substantially, which should help me gain horsepower without extending RPM, which the TPI will more or less prevent from happening anyway.

 

Just an FYI: Last week I took the car to the drag strip, and in the nice cool air it responded very well: 13.66 @ 101.18mph with a 2.009 60 foot. My new best ET by 2 tenths, and my best mph by 2mph! It ran fast enough to get me thrown out for not having a helmet, so I only got one run. Good thing I made it count.

http://www.youtube.com/watch?v=xs-ggrfooLk

 

Nice numbers and 1/4 mile runs!

 

Do you know what your race weight was for that run? Thats really close to my B-body LT1 swap with bolt-ons in terms of ET and trap speed.

 

I have no idea what the weight is, but I'm sure it isn't light. It's a fully optioned car, plus 100lbs of stereo equipment and my fat *** in it. All added up, it's probably 3800lbs.

 

That's where I screwed up. I never weighed mine stock. Now with the swap and "weight loss" project, I'll never know exactly how much I removed. And, yeah. If I could drive, sitting over the right rear wheel, at least it would be productive ballast!

 

My GTA's race weight with me in it + laptop bag and a full tank was 3770lbs. The scale only measured in 20lb increments.

My car is a fat heavy beastie.

No problems getting out of its own way though. Surprising for a baby cammed iron headed LT1.